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Symmetric Crypto Random Generators  Steganography Digital signatures Certificates management in OMU Compression and crypto Digital Code Signing
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  1. Operations performed in converting encrypted messages to plain text without initial knowledge of the crypto-algorithm and/or key employed in the encryption. [NIS]
  2. The study of encrypted texts.

Although cryptography is an ancient art, it had not been widely used until late 19th century. And outside military, real mass application started only with widespread use of personal computers.  Before, say, 1990 outside of government classified systems and military the primary users of encryption have been financial institutions with their electronic fund transfer operations. The advent of the Internet in late 80th/early 90th as a cheap vehicle for transferring information electronically to all parts of the world and its inherent lack of security has inspired the use of encryption as a protection for sensitive information. As a direct result, new and rather esoteric encryption algorithms has been developed and put in widespread use to meet those challenges.

One result of the growing economic use of the Internet is the recognition by users and vendors alike that there is a need to provide a mechanism to protect the confidentiality of Internet users and the content of their transactions. Here encryption naturally comes to into play.

This page may help students by providing annotated links to the main topics in cryptography algorithms, including single-key cryptography algorithms, public-key cryptography algorithms, key negotiation algorithms, message authentication algorithms (digital signatures).  Essentially basic information and it can be found also on any other similar university course pages.

Please note that many of those algorithms represent a new areas of computer science.

In Internet age cryptography is important for the same reasons that photo IDs were important before and fences were important even before that. Cryptography offers three essential services that protect internet user and his/her data from theft and fraud. These services are authentication, integrity, and confidentiality.  The latter in view of latest NSA revelations is mostly illusionary unless you take special measures such as dual layer encryption and  steganography.  Especially vulnerable are any data stored in the cloud, especially your address books and emails that are stored in Web mail accounts such as Gmail, hotmail or Yahoo mail.  

There's a saying that "on the Internet, nobody knows you're a dog." And one of the things that make Internet so attractive, I would say addictive, is the (fake) anonymity it offers. In reality this anonymity is an illusion. Moreover most of your activities are probably stored for five years or more. Some are stored probably for life. In other words you are like a bug under the microscope.

With the current capabilities of various companies (Google, Facebook, Amazon to name a few) and agencies to intercept and log your internet communications this anonymity is greatly exaggerated. Email is probably the most abused type of service. It is routinely intercepted and analyzed. And actually "could email" is a remote storage that does not belong to you so in no way we can talk seriously about anonymity of such email. 

Transborder communication are the natural, by law, domain of national three letter agencies. For example all your emails to addresses outside the country are intercepted and stored as a matter of policy.  

The US government intercept approximately 1.6 billion messages a day. You also can be pretty sure that all your email to foreign addresses for the last decade or so is stored somewhere and can be retrieved and analyzed in case of necessity. Capabilities of modern storage goes into petabytes(1015) with large government agencies able to store Zettabytes(1021). If we assume that there are 100 millions(108) of active Internet users in the USA (out of 300 million population), then one just one petabyte storage allows approximately 107 per individual. Ten megabytes is a lot of storage for compressed text information and corresponds probably to 100 megabytes uncompressed. If we assume that information is stored for 10 years that's 10 megabytes per year. And this is just one petabyte, the storage  that even a medium income individual can assemble without much problems.

One petabyte is 1000 gigabytes which can be stored on 250 4 GB drives, $200 each. So we are taking about something like $70K ($50K for drives and, say,  $20K for hardware and software for those drives, assuming 12 drives per server, such as RB-1200 ($700) ). There are a number of different 2U cases that feature 12x3.5" hot swap bays (3 vertically x 4 horizontally -- See Supermicro's SC827)

Any defense from a "fishbowl" effect of such massive storage is based on cryptography or steganography (you can hide messages and "junk" plaintext with a side effect of increasing storage requirements.

Snowden revelations also greatly increased the value of non-standard, custom crypto-algorithms. Now after Snowden revelation we can assume that newer standard crypto algorithms are compromised (it's still unclear if DEC was compromised, as at the time of its creation the priorities were different).  That means that you need to use "pre-encryption" with non-standard algorithms and additional key even if your channel is encrypted to ensure privacy of transmission. 

With your Web access logs situation is a little bit more fuzzy. If you use particular IP from a particular provider, it not that difficult to log all your web activity. All your Google searches and all you activity on Youtube is logged, no question about it :-). And those logs probably are stored for a very long time. But here we are talking about logs, and the data you've sent, not the data you retrieve. If you use proxies like anonimizers it's more difficult, but at the same time it automatically makes your traffic more suspicious and it comes under higher level of scrutiny. The same is true about usage of PGP for emails. Steganography is much more subtle way to ensure privacy of your emails that PGP encryption. Using "Aesop language" can be viewed as the simplest way to apply steganography to your emails.

In any case without cryptography, privacy of your Internet activities is non-existent. The right assumption is that when you access Internet you are living in a fishbowl.

If you're trying to conduct business you face different problem. Here you need to assure your customers that "you are you, not some impostor".  Customers need to be sure that that they're ordering  from real businesses. Not from a fake sites designed to steal their financial information. Cryptography also offers a solution to this problem. Certificates are sometimes called "digital IDs," because they can be used to verify the identity of someone you don't know. This process is called "authentication". Certificates can be used with another technique, "digital signatures", to ensure that nobody impersonate you and/or to protect the integrity of data. It's very easy to forge email (although primitive forging is easy to detect), but it's really hard to forge a digitally signed email message.

The level we discuss this subject is very basic and mainly oriented on CS students of Network Security course or similar.  I would like to stress again that I not specialist in this particular area, but I hope it still useful for computer science students, especially to students of "Network Security" course that I used to teach. 

Crypto algorithms and compression

Bijective compression means that for any file X, F( F'( X ) ) == X. (F is either the compressor or decompressor, and F' is its opposite). this defines  lossless compression.  This type of compression is important in compressing files and in crypto algorithms.

Custom compression now is often used as a standard first phase of encryption of large chunks of texts. It eliminates redundancy and thus creates significant additional difficulties for attempts to break particular cipher in many case making them simply impossible (using salt to make it unique and if a non standard algorithms with no headers is used). It destroys the notion of the dictionary and of a known plaintext. Even alphabet used became unknown.

See also

Symmetric Crypto Algorithms

Introduction to Public-Key Cryptography

Digital Signatures

Dr. Nikolai Bezroukov

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Old News ;-)

[Apr 30, 2020] CIA BND s Rubicon Op: Rooting National Security on One Swiss Firm s Devices Was Bad Idea

Notable quotes:
"... Mauro Conti notes that while it's hard for him to explain the specific technical details of the "holes" in the Swiss company's devices which helped the CIA and BND to intercept information, modern surveillance capabilities are even more vast. ..."
"... "There are a lot of ways to add 'backdoors' and 'covert channels' to systems, " he explains. "If well-designed, these are very difficult to be detected even when devices are carefully inspected. Just to cite an example, in recent activities of my research group, we showed the possibility of building a covert channel on a smartphone by using energy consumption modulation – a 'channel' that is far underestimated (and hence not inspected) to be used to 'send out' information in a 'stealthy' way". ..."
Feb 14, 2020 |

Relying on a single firm's devices to ensure national security and transmit state secrets was obviously a bad idea, says Mauro Conti, full professor in computer science, commenting on the recently exposed collaboration between a Switzerland-based global encryption company and the US and German intelligence services. The US Central Intelligence Agency (CIA) and Germany's Federal Intelligence Service (BND) had covertly run Crypto AG , a Swiss company that made and sold encryption equipment to over 120 countries for decades, making it possible for American and German spies to crack other nations' top secrets, The Washington Post, German public broadcaster ZDF and Switzerland's SRF revealed this week.

Switzerland's Neutrality Was Seen as 'Plus' for the Company

For the countries which used Crypto AG's services, including nations in Europe, Africa, the Middle East, Latin America and even the Vatican, Switzerland's neutrality was an important factor. Nevertheless, Washington's major Cold War rival – the USSR – was never one of the company's customers. For the countries which used Crypto AG's services, including nations in Europe, Africa, the Middle East, Latin America and even the Vatican, Switzerland's neutrality was an important factor. Nevertheless, Washington's major Cold War rival – the USSR – was never one of the company's customers.

"The location of the company was probably considered by some 'a plus' for the company to be trusted. For those, there will probably be a re-thinking of this bias, but maybe not enough to change the decision that they took", says Mauro Conti, full professor in computer science, and head of SPRITZ Security and Privacy Research Group.
According to Conti, "rooting the security of an organisation on 'a single' company/device, might also be a bad practice that could and should have been avoided".
"Keeping information, as well as operations like this, secret is always a 'battle of wits' between entities that have two opposite goals,", the professor elaborates. "If it has been uncovered for a long time, it just means that who was running it, did it quite well, and/or that those who were supposed to find this out, did not put in enough effort, including working on the wrong assumptions."
According to reports, the earliest mentions of the clandestine operation in the press go back to 1992 and 1995. On 10 December 1995, The Baltimore Sun According to reports, the earliest mentions of the clandestine operation in the press go back to 1992 and 1995. On 10 December 1995, The Baltimore Sun broke the news that the US National Security Agency (NSA) "secretly rigged Crypto AG machines" so that American spies could easily decrypt their codes, citing former company employees and documents. However, the story was resolutely denied by the US and German intelligence services. Responding to the question as to why it has been found out now, Conti noted laconically that "the battle of wits and capabilities to support them just turned in favour of the other player". Responding to the question as to why it has been found out now, Conti noted laconically that "the battle of wits and capabilities to support them just turned in favour of the other player". Responding to the question as to why it has been found out now, Conti noted laconically that "the battle of wits and capabilities to support them just turned in favour of the other player". Frederick Florin Former US National Security Agency (NSA) contractor and whistle blower Edward Snowden is seen on screen in a control room as he speaks via video link from Russia as he takes part in a round table meeting on the subject of "Improving the protection of whistleblowers" on March 15, 2019, at the Council of Europe in Strasbourg, eastern France.

Hundred-Percent Privacy is No Longer Possible

Mauro Conti notes that while it's hard for him to explain the specific technical details of the "holes" in the Swiss company's devices which helped the CIA and BND to intercept information, modern surveillance capabilities are even more vast. Mauro Conti notes that while it's hard for him to explain the specific technical details of the "holes" in the Swiss company's devices which helped the CIA and BND to intercept information, modern surveillance capabilities are even more vast.

"There are a lot of ways to add 'backdoors' and 'covert channels' to systems, " he explains. "If well-designed, these are very difficult to be detected even when devices are carefully inspected. Just to cite an example, in recent activities of my research group, we showed the possibility of building a covert channel on a smartphone by using energy consumption modulation – a 'channel' that is far underestimated (and hence not inspected) to be used to 'send out' information in a 'stealthy' way".
Operation Rubicon, which was large in scale, predated the sophisticated data-intercepting activities exposed by former CIA subcontractor Edward Snowden, who leaked highly classified information about the Operation Rubicon, which was large in scale, predated the sophisticated data-intercepting activities exposed by former CIA subcontractor Edward Snowden, who leaked highly classified information about the NSA's programme, code-named Prism, in 2013 .

Reportedly launched in 2007, Prism allowed the US intelligence community to collect large amounts of data on Americans and foreign citizens.

Four years later, WikiLeaks released a series of documents titled Vault 7 which shed light on the CIA's activities and cutting-edge capabilities in performing electronic surveillance and cyber-warfare. One has to wonder whether there's anything that can guarantee privacy in our time. The professor's answer is "no, as scary as it might sound" if one means a 100% guarantee.

"It is not just matter of our times, but definitely the digital era definitely helps a lot to expose information, as well as to retrieve it", Conti underscores. "In addition, underestimating the problem does not help."

"In addition, underestimating the problem does not help."

How It All Began: Russian-Born Émigré & American Cryptologist

While, according to the report, the beginning of the CIA-BND secret collaboration, code-named Operation Rubicon, dates back to the 1970s, Crypto AG's links to the CIA can be found even deeper in history.

The company's founder, Boris Hagelin, was born in Russia and fled to Sweden after the 1917 Revolution. In the 1930s, he made friends with William F. Friedman, the leading US cryptanalyst. In 1940 Hagelin moved to the US and started selling portable encryption machines to the US military.

After the Second World War, Hagelin returned to Europe and established his business in Switzerland. In 1951 he and William Friedman, who was at the time head of the cryptographic division of the US Armed Forces Security Agency (AFSA) struck an agreement that Hagelin would sell his devices only to countries approved by the US.

In 1970 Crypto was bought out by the West Germany and American intelligence services. Presumably, at least four countries, namely Israel, Britain, Sweden and Switzerland knew about the clandestine operation or even had access to intercepted information.

In the early 1990s, BND sold its share in the company to the CIA. In 2018 Crypto AG was liquidated while two other separate entities emerged – Crypto International and CyOne Security AG.

As Reuters While, according to the report, the beginning of the CIA-BND secret collaboration, code-named Operation Rubicon, dates back to the 1970s, Crypto AG's links to the CIA can be found even deeper in history.

'F**k Your Top Secret!': Trial Begins for Ex-CIA Employee Accused of 'Vault 7' Leak
CIA Secretly Owned World's Top Maker of Encryption Devices - Reports
News of CIA Owning Swiss Maker of Encryption Devices Shatters Idea of Country's Neutrality - Scholar
Tags: neutrality , Switzerland , encryption , NSA , CIA , German Federal Intelligence Service (BND) , Intelligence , Germany , United States Community standards

All comments

[Apr 30, 2020] After WW2 the Brits collected as many Enigma machines as they could get their hands on and gave them to all the commonwealth countries, and a few others, saying they were un-crackable all the while knowing that wasn't the case and they could read them like the daily papers

Apr 30, 2020 |

xxx logicalman 4/27/2020, 1:40:42 PM (Edited)

Perfidious Albion.

After WW2 the Brits collected as many Enigma machines as they could get their hands on and gave them to all the commonwealth countries, and a few others, saying they were un-crackable all the while knowing that wasn't the case and they could read them like the daily papers. That's why Enigma was top secret for at least 40 years - some details will likely be kept secret for ever.

My dad worked on cracking it - got a medal for his work 50 years after the end of WW2. Didn't let on to anyone until his work was declassified. I had some very interesting conversations with him towards the end of his life.

He was invited down to Bletchley for the official switch-on when the Colossus rebuild was finished.

[Apr 03, 2020] Why Printers Add Secret Tracking Dots

Notable quotes:
"... However, he adds, "I hope that folks think about their operational security and also about how journalists can protect themselves – and their sources as well." ..."
Apr 03, 2020 |

They're almost invisible but contain a hidden code – and their presence on a leaked document has sparked speculation about their usefulness to FBI investigators. BBC Future |

On 3 June, 2017, FBI agents arrived at the house of government contractor Reality Leigh Winner in Augusta, Georgia. They had spent the last two days investigating a top secret classified document that had allegedly been leaked to the pres s. In order to track down Winner, agents claim they had carefully studied copies of the document provided by online news site The Intercept and noticed creases suggesting that the pages had been printed and "hand-carried out of a secured space".

In an affidavit , the FBI alleges that Winner admitted printing the National Security Agency (NSA) report and sending it to The Intercept. Shortly after a story about the leak was published, charges against Winner were made public.

At that point, experts began taking a closer look at the document, now publicly available on the web. They discovered something else of interest: yellow dots in a roughly rectangular pattern repeated throughout the page. They were barely visible to the naked eye, but formed a coded design. After some quick analysis , they seemed to reveal the exact date and time that the pages in question were printed: 06:20 on 9 May, 2017 – at least, this is likely to be the time on the printer's internal clock at that moment. The dots also encode a serial number for the printer.

These "microdots" are well known to security researchers and civil liberties campaigners. Many colour printers add them to documents without people ever knowing they're there.

Dots from a HP Laserjet printer, illuminated with blue light. Credit: Florian Heise/Wikipedia .

In this case, the FBI has not said publicly that these microdots were used to help identify their suspect, and the bureau declined to comment for this article. The US Department of Justice, which published news of the charges against Winner, also declined to provide further clarification.

In a statement , The Intercept said, "Winner faces allegations that have not been proven. The same is true of the FBI's claims about how it came to arrest Winner."

But the presence of microdots on what is now a high-profile document (against the NSA's wishes) has sparked great interest.

"Zooming in on the document, they were pretty obvious," says Ted Han at cataloguing platform Document Cloud , who was one of the first to notice them. "It is interesting and notable that this stuff is out there."

Another observer was security researcher Rob Graham, who published a blog post explaining how to identify and decode the dots. Based on their positions when plotted against a grid, they denote specific hours, minutes, dates and numbers. Several security experts who decoded the dots came up with the same print time and date.

Microdots have existed for many years. The Electronic Frontier Foundation (EFF) maintains a list of colour printers known to use them . The images below, captured by the EFF, demonstrate how to decode them:

These yellow dots, magnified 60 times, were found on a Xerox printout. Credit: Electronic Frontier Foundation/CC BY 3.0 .

The dots become more easily visible when magnified and photographed under a blue LED flashlight. Credit: Electronic Frontier Foundation/CC BY 3.0 .

For further clarity, the dots here are annotated. So what does the shape mean? Credit: Electronic Frontier Foundation/CC BY 3.0 .

The position of the dots reveals the time and date of the printout, and the serial number of the device. Credit: Electronic Frontier Foundation/CC BY 3.0 .

As well as perhaps being of interest to spies, microdots have other potential uses, says Tim Bennett, a data analyst at software consultancy Vector 5 who also examined the allegedly leaked NSA document.

"People could use this to check for forgeries," he explains. "If they get a document and someone says it's from 2005, [the microdots might reveal] it's from the last several months."

If you do encounter microdots on a document at some point, the EFF has an online tool that should reveal what information the pattern encodes.

Hidden Messages

Similar kinds of steganography – secret messages hidden in plain sight – have been around for much longer.

Slightly more famously, many banknotes around the world feature a peculiar five-point pattern called the Eurion constellation . In an effort to avoid counterfeiting, many photocopiers and scanners are programmed not to produce copies of the banknotes when this pattern is recognised.

The NSA itself points to a fascinating historical example of tiny dots forming messages – from World War Two. German spies in Mexico were found to have taped tiny dots inside the envelope concealing a memo for contacts in Lisbon.

At the time, these spies were operating undercover and were trying to get materials from Germany , such as radio equipment and secret ink. The Allies intercepted these messages, however, and disrupted the mission. The tiny dots used by the Germans were often simply bits of unencrypted text miniaturised to the size of a full-stop.

This sort of communication was widely used during WWII and afterwards, notably during the Cold War. There are reports of agents operating for the Soviet Union, but based undercover in West Germany and using letter drops to transmit these messages .

Microdots taped inside the label of an envelope sent by German spies in Mexico City to Lisbon during World War Two. Credit: Wikipedia .

And today, anyone can try using microtext to protect their property – some companies, such as Alpha Dot in the UK , sell little vials of permanent adhesive full of pin-head sized dots, which are covered in microscopic text containing a unique serial number. If the police recover a stolen item, the number can in theory be used to match it with its owner.

Many examples of these miniature messages do not involve a coded pattern as with the output of many colour printers, but they remain good examples of how miniscule dispatches physically applied to documents or objects can leave an identifying trail.

Some forms of text-based steganography don't even use alphanumeric characters or symbols at all. Alan Woodward, a security expert at the University of Surrey, notes the example of 'Snow' – Steganographic Nature Of Whitespace – which places spaces and tabs at the end of lines in a piece of text. The particular number and order of these white spaces can be used to encode an invisible message.

"Locating trailing whitespace in text is like finding a polar bear in a snowstorm," the Snow website explains .

Woodward points out, though, that there are usually multiple ways of tracing documents back to whoever printed or accessed them.

"Organisations such as the NSA have logs of every time something is printed, not just methods of tracking paper once printed," he says. "They know that people know about the yellow dots and so they don't rely upon it for traceability."

There is a long-running debate over whether it is ethical for printers to be attaching this information to documents without users knowing. In fact, there has even been a suggestion that it is a violation of human rights and one MIT project has tracked more than 45,000 complaints to printer companies about the technology.

Still, many believe that the use of covert measures to ensure the secrecy of classified documents remains necessary in some cases.

"There are things that governments should be able to keep secret," says Ted Han.

However, he adds, "I hope that folks think about their operational security and also about how journalists can protect themselves – and their sources as well."

[Feb 14, 2020]

Feb 14, 2020 |

Stay Connected on the Go with Breaking News Alerts Get the Microsoft News App for your phone, on iOS and Android No thanks Download now msn news powered by Microsoft News

[Mar 02, 2018] A proposal for passing some small chunks information undetected

Mar 02, 2018 |

mark data-comment-timestamp="1519975426"

Hillarys Server Fri, 03/02/2018 - 02:00 Permalink

I've used a very simple code.

You know those wavy lines that some people put above and below their automatic signature, e-mail address and phone number?

When I wanted to send a private chat using office e-mail I'd make that wavy automatic signature line using the decorative "widgets" font.

The receiver would take the wavy widgets fonts line and change the font from widget symbols to "Cyrillic" font and copy paste the cyrillic line into Google Translate and translate it from Russian into English. And that was my private message.

And to write back he'd just write a message in English, translate it into Russian, change the Cyrillic font into widgets, make the widgets small like a decorative wavy line and stick it above and below his automatic signature.

I don't think anyone would think, Hey this decorative wavy signature line might actually be a coded message in Amharic, Russian or Hebrew, I'll change the font and into all of the world's alphabets one by one and see.

Helena Bonham-Carter -> Hillarys Server Fri, 03/02/2018 - 02:08 Permalink

Your message will be detected as suspicious in 2 seconds because it's a statistical outlier compared to other comms. If it's ranked as suspicious enough (when combined with other detection criteria) to land on an analyst's desk, they'll figure it out in 5 minutes. Use peer-reviewed cryptographic implementations or go home.

Doom and Dust -> Helena Bonham-Carter Fri, 03/02/2018 - 02:12 Permalink

Even the best encryption is useless when your RNG is compromised.

Guess where the most advanced and widely used RNGs are designed and located?

Helena Bonham-Carter -> Doom and Dust Fri, 03/02/2018 - 02:17 Permalink

The most advanced, and the most widely used, are not the same product.

The most widely used are the RNG's integrated into consumer CPU's and OS's. Many are backdoored.

The most advanced are manufactured by small firms in a number of countries.

Doom and Dust -> Helena Bonham-Carter Fri, 03/02/2018 - 02:22 Permalink

RNGs in CPUs and other devices are useless for true encryption since they are pseudo-random by definition.

True RNGs are manufactured and maintained from nuclear sources by a small number of companies mostly from one single very small country. Surely you can guess it.

Helena Bonham-Carter -> Doom and Dust Fri, 03/02/2018 - 02:28 Permalink

Expand your horizons.

Helena Bonham-Carter -> Doom and Dust Fri, 03/02/2018 - 02:32 Permalink

There are CPU-integrated HWRNG's using thermal noise. They are not pseudorandom by definition. There are HWRNG's generating true randomness based on beam splitters, shot noise, reverse-biased semiconductor junctions, the photoelectric effect, and more. If you want to share some knowledge, do it.

Doom and Dust -> Helena Bonham-Carter Fri, 03/02/2018 - 02:44 Permalink

Numbers derived from the deterministic processes you mention, no matter how many, are not random and can not be used for high-end encryption or simulations like the Monte Carlo method.

One of the most important and least known books of the 20th century was published in the 50s by the RAND Corporation, titled "A Million Random Digits with 100,000 Normal Deviates". For decades it was THE source of random numbers used around the Western world.

True random numbers are rare and very hard to obtain because they rely on measurements of indeterministic processes like atomic decay.

Helena Bonham-Carter -> Doom and Dust Fri, 03/02/2018 - 03:08 Permalink

All of the methods I mentioned are nondeterministic and, in proper implementation, are widely deployed for generating key material. Everyone with an EECS education has heard of the RAND book.

[Jun 09, 2017] Youll never guess where Russian spies are hiding their control servers

The article is a click bait (Article says nothing about where Russians hide their C&C servers, only where they hide their URLs), the idea is not new (a variant of steganography, as foetusinc noted in his comment below), and probably those groups are not Russian, but still hiding URL for the control server in spam on some useless social forums like Britney Spears fan club is pretty clever idea...
Jun 09, 2017 |

According to a report published Tuesday by researchers from antivirus provider Eset, a recently discovered backdoor Trojan used comments posted to Britney Spears's official Instagram account to locate the control server

... ... ...

The extension will look at each photo's comment and will compute a custom hash value. If the hash matches 183, it will then run this regular expression on the comment in order to obtain the path of the URL:


Looking at the photo's comments, there was only one for which the hash matches 183. This comment was posted on February 6, while the original photo was posted in early January. Taking the comment and running it through the regex, you get the following URL:

Looking a bit more closely at the regular expression, we see it is looking for either @|# or the Unicode character \200d. This character is actually a non-printable character called 'Zero Width Joiner,' normally used to separate emojis. Pasting the actual comment or looking at its source, you can see that this character precedes each character that makes the path of the URL:

smith2155#2hot make loveid to her, uupss #Hot #X

When resolving this shortened link, it leads to , which was used in the past as a watering hole C&C by the Turla crew.

foetusinc Ars Scholae Palatinae Jun 6, 2017 8:16 PM Popular

So spammy social media comments are the new numbers stations ? I've assumed for a while that somebody out there must be doing something similar with image steganography, but leave it to the Russians to come up with something this brilliantly simple.
dramamoose Smack-Fu Master, in training Jun 6, 2017 6:52 PM
That's brilliant, and incredibly similar in principle if not execution to tried and true espionage techniques for communication; codewords in BBC broadcasts, newspaper ads sending information, etc. Why risk using a central server which can be eliminated if you can just hide your information in the incredible amount of simple-to-post, easier-to-read social networking out there. If you covered enough sites, you'd likely be able to slip in requests that even a security pro wouldn't be able to pick up. Sure, there are some people who don't use Facebook, Twitter, Instagram, or Reddit, but there aren't that many. Combine it with a few regional networking sites and you could probably hide the traffic in a way that even somebody looking for the transmissions couldn't find them.

[Dec 26, 2016] Google Releases Tool To Find Common Crypto Bugs

Dec 26, 2016 |
( 22

Posted by BeauHD on Monday December 19, 2016 @05:45PM from the come-out-come-out-wherever-you-are dept.

Trailrunner7 quotes a report from On the Wire:

Google has released a new set of tests it uses to probe cryptographic libraries for vulnerabilities to known attacks . The tests can be used against most kinds of crypto algorithms and the company already has found 40 new weaknesses in existing algorithms. The tests are called Project Wycheproof , and Google's engineers designed them to help developers implement crypto libraries without having to become experts. Cryptographic libraries can be quite difficult to implement and making errors can lead to serious security problems. Attackers often will look for weak crypto implementations as a means of circumventing strong encryption in a target app. Among the issues that Google's engineers found with the Project Wycheproof tests is one in ECDH that allows an attacker to recover the private key in some circumstances.

The bug is the result of some libraries not checking the elliptic curve points that they get from outside sources.

"In cryptography, subtle mistakes can have catastrophic consequences, and mistakes in open source cryptographic software libraries repeat too often and remain undiscovered for too long.

Good implementation guidelines, however, are hard to come by: understanding how to implement cryptography securely requires digesting decades' worth of academic literature.

We recognize that software engineers fix and prevent bugs with unit testing, and we found that many cryptographic issues can be resolved by the same means," Daniel Bleichenbacher and Thai Duong, security engineers at Google, said in a post announcing the tool release.

"Encodings of public keys typically contain the curve for the public key point.

If such an encoding is used in the key exchange then it is important to check that the public and secret key used to compute the shared ECDH secret are using the same curve. Some libraries fail to do this check," Google's documentation says.

[Dec 09, 2015] Three ways to easily encrypt your data on Linux

Ok, so you need to quickly encrypt the contents of you pen drive. The easiest solution is to compress them using the 7z archive file format, that is open source, cross-platform, and supports 256-bit encryption using the AES algorithm.

Linux has LUKS, which can encrypt partitions or do whole-disk encryption. When you create a new partition, the partition manager will give you the option to, say, encrypt the /home directory.

Encrypt with Seahorse

The third option that I will show basically utilizes the popular GNU PG tool to encrypt anything you want in your disk. What we need to install first are the following packages: gpg, seahorse, seahorse-nautilus, seahorse-daemon, and seahorse-contracts which is needed if you're using ElementaryOS like I do. The encryption will be based on a key that we need to create first by opening a terminal, and typing the following command:

[Apr 21, 2015] Documentary Inside NSA - Discovery Channel

Looks like it was created in early 90th, judging from equipment we see.
Apr 21, 2014| YouTube

Documentary Inside NSA - Discovery Channel

[Apr 21, 2015] The Future of Freedom: A Feature Interview with NSA Whistleblower William Binney (2015)

Jan 28, 2015 |

A 36-year veteran of America's Intelligence Community, William Binney resigned from his position as Director for Global Communications Intelligence (COMINT) at the National Security Agency (NSA) and blew the whistle, after discovering that his efforts to protect the privacy and security of Americans were being undermined by those above him in the chain of command.

The NSA data-monitoring program which Binney and his team had developed -- codenamed ThinThread -- was being aimed not at foreign targets as intended, but at Americans (codenamed as Stellar Wind); destroying privacy here and around the world. Binney voices his call to action for the billions of individuals whose rights are currently being violated.

William Binney speaks out in this feature-length interview with Tragedy and Hope's Richard Grove, focused on the topic of the ever-growing Surveillance State in America.

On January 22, 2015: (Berlin, Germany) – The Government Accountability Project (GAP) is proud to announce that retired NSA Technical Director and GAP client, William "Bill" Binney, will accept the Sam Adams Associates for Integrity in Intelligence Award today in Berlin, Germany. The award is presented annually by the Sam Adams Associates for Integrity in Intelligence (SAAII) to a professional who has taken a strong stand for ethics and integrity.

Would You Like to Know More?

Subscribe to the Peace Revolution podcast produced by Tragedy and Hope:

[Apr 21, 2015] NSA Whistleblower - Jesselyn Radack & Thomas Drake London Real

Mar 16, 2014 | YouTube

Jesselyn Radack is Edward Snowden's Attorney
Thomas Drake is an Former NSA Executive & Whistleblower
Bulletproof Coffee

[Dec 28, 2012] Senate Renews FISA Warrantless Wiretapping Program

December 28, 2012 |

The US Senate on Friday reauthorized the warrantless wiretapping program started under President George W. Bush by a 73 to 23 vote, easily evading the several amendments proposed to check its dangerous surveillance powers.

The FISA Amendments Act of 2008 authorized broad, warrantless surveillance of Americans' international communications, checked only by a secretive Foreign Intelligence Surveillance Court that doesn't make it's activities and procedures available to the public.

Even though the government has acknowledged that the secretive program has exceeded its legal limits, violating Americans' Fourth Amendment constitutional rights, the Obama administration has aggressively pushed for its full renewal.

When the law was passed in 2008 it amended the Bush administration's initial program and broadened powers for domestic surveillance. President Obama was a presidential candidate at the time, and warned that, while he was voting for its passage, it "does not resolve all of the concerns that we have about President Bush's abuse of executive power."

However, as President Obama has fully embraced the unchecked executive powers and secretive surveillance capabilities built into the FISA Amendment. And the controversy that the bill conjured in 2008 is contrasted with the subdued acceptance of it in 2012.

"The Bush administration's program of warrantless wiretapping, once considered a radical threat to the Fourth Amendment, has become institutionalized for another five years," said Michelle Richardson, the ACLU's legislative counsel.

Several tame amendment were proposed by Senators Ron Wyden, Rand Paul, and Jeff Merkely to try and rein in the surveillance program. But they were all rejected, and the Obama administration has refused to release any further information about it.

"The only thing the public really knows about it so far," writes Julian Sanchez, a policy scholar at the Cato Institute, "is that it was almost immediately misused, resulting in 'significant and systemic' overcollection of Americans' purely domestic communications. Subsequent reporting revealed that the improperly 'overcollected' communications could number in the millions, and included former president Clinton's private e-mails. So naturally, the Senate is charging ahead toward the renewal of these sweeping powers without hearings or debate."

As the American for Civil Liberties Union has explained, the Director of National Intelligence James Clapper says "it isn't even 'reasonably possible' to estimate how many Americans are swept up in the NSA's expansive dragnet."

The Obama administration, as is usual in cases where they disregard the Constitution, promises this mass surveillance comes with strong safeguards and accountability. In reality, the war on terrorism is continuing to be used to justify major infringements on the civil liberties of Americans.

[Dec 11, 2011] San Francisco Team Solves DARPA Shredder Challenge by Elizabeth Montalbano

I you do not anybody to read particular document don't shred, burn.
12/05/11 | InformationWeek

A San Francisco-based programming team pieced together five shredded documents in 33 days to win the U.S. Defense Advanced Research Projects Agency's (DARPA's) Shredder Challenge.

The three programmers used custom computer-vision algorithms to assemble the complex puzzles comprised of documents, which were shredded into more than 10,000 pieces. The team spent nearly 600 hours creating the algorithms, designing them to suggest fragment pairings.

The programmers were then able to manually verify the pairings to piece together the documents, which had Antonio Prohias, the creator of the Spy vs. Spy comic strip, as their common, running theme.

DARPA organizers were surprised not only that all of the puzzles were solved, but in a relatively short time.

"Lots of experts were skeptical that a solution could be produced at all, let alone within the short time frame," says DARPA's Dan Kaufman.

He says the most effective approaches combined computational tools, crowdsourcing, and "clever detective work."

[Dec 11, 2011] Cryptographers Believe 'Size Does Matter' to Stay Safe Online by Royal Holloway

12/02/11 | University of London

Royal Holloway, University of London researchers are analyzing the Transport Layer Security (TLS) system to identify weaknesses. The TLS system is designed to ensure the security and safety of online personal information, but vulnerabilities were found in version 1.0 of the system. The researchers say that TLS version 1.2 offers improved security.

"Our analysis of TLS version 1.2 gives us higher confidence that the data we share online will be kept safe, secure, and private," says Royal Holloway professor Kenny Paterson. TLS encrypts messages as they are transmitted across the Internet, keeping personal data insulated against attack. The researchers have found only one vulnerability in the latest version of TLS. "There is still scope for a 'distinguishing attack' against TLS 1.2, where an attacker could tell whether a user has sent a 'yes' or a 'no' during a transaction, for example," Paterson says.

However, he notes that this kind of attack is considered theoretical, and it is very unlikely that it would actually arise in practice. TLS uses a Message Authentication Code (MAC) tag to help provide security, and for the Royal Holloway attack to work, the MAC tag would need to be small.

[Feb 24 2003] Program Hides Secret Messages in Executables By Kevin Poulsen

I doubt that this is promising as described, but something along those lines (with predefined set of equivalencies) can be developed further. Consider instructions equivalencies as some kind of bit mask that can be applied to any of the program strings
Feb 24 2003 | SecurityFocus

Netizens with extreme privacy needs got a new tool for their cyber utility belts recently with the release of an application that lets users hide secret messages in virtually any executable computer program, without changing the program's size or affecting its operation.

The tool is called "Hydan," an old English word for the act of hiding something, and it's part of a research project by Columbia University computer science masters student Rakan El-Khalil, who showed off the program to a small group of open-source programmers and hackers gathered at the second annual CodeCon conference in San Francisco on Sunday.

Hydan is a novel development in the field of steganography -- the science of burying secret messages in seemingly innocuous content. Popular stego programs operate on image and music files, where a secret missive can be hidden without altering the content enough to be perceived by human senses. But because they contain instructions for a computer's processor, executable files are less forgiving of tampering. Improperly changing a single bit of executable code can render an application completely unusable.

El-Khalil's research focused on redundancies in the Intel x86 instruction set -- places where at least two different instructions are effectively the same. Each choice between two redundant options can represent a single bit of data. "The problem with program binaries is there is just not a lot of redundancy in them," said El-Khalil.

He found some of that useful redundancy in the instructions that tell the computer to add or subtract.

A computer instruction to add the number 50 to another value, for example, can be replaced with an instruction to subtract the number -50 instead. Mathematically, the instructions are the same. In choosing between the two, a stego program can get one bit of covert storage out of each addition or subtraction operation in the executable -- without changing the way the application runs, or adding a single byte to its size. "If we use a scenario in which addition is zero, and subtraction is one, we can just go through and flip them as needed," El-Khalil explained.

El-Khalil concedes that the method is imperfect -- an application that's been impressed with a secret message has considerably more "negative subtractions" than an unadulterated program, making it easy to pick out through a statistical analysis. Hydan could also break programs that are self-modifying or employ other unconventional techniques. And it's less efficient than stego programs for image and sound files: good steganography for a JPEG file can hide one byte of storage in 17 bytes of image, while Hydan's ratio is one byte of storage to 150 bytes of code.

Future versions of Hydan will boost that capacity by finding different places to code data, such as in the order of a program's functions, and the order in which arguments are passed to those functions. For now, the application is still powerful enough to secretly stash the United States Constitution and the Declaration of Independence in a single copy of Microsoft Word.

Beyond the covert uses, the technology could be used to attach a digital signature to an application, or to embed an executable with a virtual watermark.

[Feb 5, 2003] The Crypto Gardening Guide and Planting Tips by Peter Gutmann, [email protected]


Question H: How flexible is your design?

Discussion: That question isn't what you think. A better way of phrasing it would be "How ambiguous is your design?". Flexibility in an abstract crypto design is a Good Thing. Ambiguity in a specification is a Bad Thing. Unfortunately, a cryptographer's flexibility is an implementer's ambiguity, or more bluntly an implementer's nightmare. An example of this is IPsec's IKE, which is so flexible/ambiguous that no two people can agree on what it should look like. As a result, even after years of work, there are still implementations that can't (or barely) interoperate, and even when they interoperate it's often only because implementers figured out what the other side was doing and adapted their code to match it.

Resolution: Once you've impressed everyone with the power and flexibility of your design, provide a sketch of a simple, straightforward, easy-to-get-right profile that implementors can work with. This is a standard feature of protocol specifications, either done explicitly (MUST/SHOULD/MAY) or implicitly when everyone ignores all but the most simple, straightforward part
of the specification. Another way of looking at this is that if implementors are going to ignore much of your design in order to make implementation practical, you want to be the one deciding which bits get used and which don't.

See also: Question G.

Question I: How big a problem are you really solving?

Discussion: Many problems pointed out in crypto papers are relatively insignificant to non-cryptographers, or can be fixed with a trivial update of existing code rather than by changing the crypto design. For example, the "correct" solution to various attacks (real and theoretical) on PKCS #1 v1.5 padding is for implementors to switch to something better such as OAEP, Simple
RSA, PSS, or whatever they're wearing in Santa Barbara this year. However, since the problem can also be resolved with "Don't do that, then", it's easier to stick with an existing solution rather than re-engineering everything to use a new protocol (see the Final Thoughts for a longer discussion on this).

Resolution: Unlike cryptographers, implementors probably won't appreciate the advantages of a design secure in the IND-CCAn+1 model where the previous was only IND-CCAn if it requires a complete redeployment of all of their products. Don't expect to see a new design widely adopted any time soon unless (a) it's being deployed in a greenfields development or (b) you've found a hole
exploitable in O(1) time by an army of script kiddies.

San's primer on key length in symmetric and asymmetric cyphers

Cryptology ePrint Archive Complete Contents

2002/185 ( PDF )
Turing, a fast stream cipher
Greg Rose and Philip Hawkes
2002/182 ( PS PS.GZ )
Oblivious Keyword Search
Wakaha Ogata and Kaoru Kurosawa
2002/142 ( PDF )
On the Applicability of Distinguishing Attacks Against Stream Ciphers
Greg Rose and Philip Hawkes
2002/131 ( PS PS.GZ PDF )
An Improved Pseudorandom Generator Based on Hardness of Factoring
Nenad Dedic and Leonid Reyzin and Salil Vadhan

AES Home Page

Cryptography Technology

Since graduating in theoretical physics and electrical engineering some 30+ years ago I have had an interest in cryptography and this has developed with the advent of progressively more powerful home computers. In recent years I have played with a number of algorithms where I have taken a particular interest in the techniques involved in making algorithms go as fast as possible.

Random findings

Springer LINK Lecture Notes in Computer Science 2133

Public-Key Crypto-systems Using Symmetric-Key Crypto-algorithms

Bruce Christianson, Bruno Crispo, and James A. Malcolm

Abstract. The prospect of quantum computing makes it timely to consider the future of public-key crypto-systems. Both factorization and discrete logarithm correspond to a single quantum measurement, upon a superposition of candidate keys transformed into the fourier domain. Accordingly, both these problems can be solved by a quantum computer in a time essentially proportional to the bit-length of the modulus, a speed-up of exponential order.

At first sight, the resulting collapse of asymmetric-key crypto-algorithms seems to herald the doom of public-key crypto-systems. However for most security services, asymmetric-key crypto-algorithms actually offer relatively little practical advantage over symmetric-key algorithms. Most of the differences popularly attributed to the choice of crypto-algorithm actually result from subtle changes in assumptions about hardware or domain management.

In fact it is straightforward to see that symmetric-key algorithms can be embodied into tamper-proof hardware in such a way as to provide equivalent function to a public-key crypto-system, but the assumption that physical tampering never occurs is too strong for practical purposes. Our aim here is to build a system which relies merely upon tamper-evident hardware, but which maintains the property that users who abuse their cryptographic modules through malice or stupidity harm only themselves, and those others who have explicitly trusted them.

LNCS 2133, p. 182 ff.

Full article in PDF (35 KB)

AES and Beyond- The IETF and Strong Crypto

Nortel slides about some crypto issues in networking. Pretty basic, but still useful.

Crypto Scientists Crack Prime Problem

Recently, a group of Indian scientists made news by announcing an algorithm that appears to be able to tell quickly whether a number is prime or not.

If you're mathematically minded, the actual downloadable primality.pdf is worth reading.

So what does this actually mean for cryptography? First, a little background.

Many of the popular common crypto algorithms work because of "something to do with prime numbers". Most security books are about that vague. So math research about primes could have interesting effects on our field. But is being able to determine whether a number is prime quickly going to be able to help or hinder us? Let's look at the RSA algorithm as an illustrative example. (It lost its patent a few years back, so it's okay to discuss now.)

... ... ...

Public key crypto algorithms such as RSA depend on there being two keys used to encrypt and decrypt a message. (Hence, the "generate a key pair" step you see when setting up many applications that use cryptography.) Every user has a complimentary set made up of a private key and a public key. Anything encrypted with the private key can be decrypted with the public key, and anything encrypted with the public key can be decrypted with the private key. Only you should have a copy of your private key, but anyone can have your public key because it's, well, public. If someone encrypts traffic with your public key, it doesn't matter to you because only you can decrypt it.

So, you're probably thinking, if I have a message to send to Jane, I want to encrypt it. I can't encrypt it with my public key, because she doesn't have my private key to decrypt it. So I'll encrypt it with my private key, and she can decrypt it with my public key. Right? Not quite, but this is a really common mistake. Sure, Jane can decrypt the message with your public key. But so can anyone else. What you need to do is encrypt the message with Jane's public key, so that only Jane's private key (which only Jane should have) can decrypt it.

So, the RSA algorithm says this:

8 and 9 are relatively prime. When broken down as much as possible,

8 = 2 x 2 x 2
9 = 3 x 3

Nothing in common.

8 and 20 are not relatively prime.

8 = 2 x 2 x 2
20 = 2 x 2 x 5

They have 2 in common, so they're not relatively prime.

If E and D are chosen correctly, then let's make C the ciphertext and P the plaintext.

C = M to the E power mod N
M = C to the D power mod N

So, something encrypted with N and E (the public key) can be solved for M -- decrypted into the plaintext. Something encrypted with N and D (the private key) can be solved for the ciphertext C. And since E and D fit together in a defined mathematical relationship as above, you cannot automatically deduce one from the other, but can encrypt and decrypt. The beauty of the modulus is that it's a one way operation. You know what the remainder is, but you'll have to try brute-forcing it to figure out whether it's C multiplied by one with a remainder of three, by two with a remainder of three... by forty thousand with a remainder of three... [grin] That takes a lot of time.

If you want to see an example of this worked out with numbers, there's a clear one at

So, back to our original point. Being able to quickly determine whether a number is prime -- what effect does that have on all this? Well, one of the weakest points about RSA and other public key algorithms is that their large prime numbers are only probably prime. It's really hard to tell whether a number with eight zillion digits is actually prime or not -- you have to try dividing it by every prime number up to half of its value or so. That's very time consuming. Since those of us that use PGP, etc., don't want to wait too long for our keys to be generated, the RSA algorithm picks values for P and Q that are very likely to be prime, but that's not known for certain.

If those numbers aren't actually prime, then there may be different solutions for the equations other than the ones that are supposed to work. So, someone might be able to decrypt a message without having the matching key -- they'd just need a matching key, if there were more than one. (That's what could happen if P and Q aren't prime.) If the new algorithm can determine whether P and Q are really prime and they're not for a given key pair, that could lead to a weakness in RSA. But if that's the case, RSA and other algorithm authors could modify their software to use the new algorithm to ensure that P and Q really are prime, and that would defeat that sort of attack.

There's a lot of sound and fury at the moment about this article, and many people are freaking out about it, but I don't think it's anything to worry about. Mathematicians haven't fully satisfied themselves yet that it's a good tester for primes -- I don't think we'll be seeing exploit code in the near future.

Information on cryptography useful collection of links:

[Oct 20, 2002] Crypto++ Library 5.0 - a Free C++ Class Library of Cryptographic Schemes

[Oct 20, 2002] Speed Comparison of Popular Crypto Algorithms

Here are speed benchmarks for some of the most popular hash algorithms and symmetric and asymmetric ciphers. All were coded in C++ or ported to C++ from C implementations, compiled with Microsoft Visual C++ 6.0 SP4 (optimize for speed, blend code generation), and ran on a Celeron 850MHz processor under Windows 2000 SP 1. Two assembly routines were used for multiple-precision addition and subtraction.

Algorithm Bytes Processed Time Taken Megabytes(2^20 bytes)/Second
CRC-32 1073741824 8.682 117.945
Adler-32 2147483648 6.970 293.831
MD2 8388608 11.276 0.709
MD5 1073741824 10.165 100.738
SHA-1 536870912 10.565 48.462
SHA-256 268435456 10.345 24.746
SHA-512 67108864 7.761 8.246
HAVAL (pass=3) 536870912 7.922 64.630
HAVAL (pass=4) 536870912 12.337 41.501
HAVAL (pass=5) 268435456 7.090 36.107
Tiger 268435456 10.325 24.794
RIPE-MD160 268435456 8.332 30.725
Panama Hash (little endian) 1073741824 7.401 138.360
Panama Hash (big endian) 1073741824 11.797 86.802
MDC/MD5 268435456 9.884 25.900
Luby-Rackoff/MD5 67108864 8.402 7.617
DES 134217728 9.945 12.871
DES-XEX3 134217728 11.716 10.925
DES-EDE3 33554432 6.740 4.748
IDEA 134217728 11.286 11.341
RC2 33554432 7.912 4.044
RC5 (r=16) 536870912 12.988 39.421
Blowfish 134217728 7.091 18.051
Diamond2 67108864 11.086 5.773
Diamond2 Lite 67108864 9.403 6.806
3-WAY 201326592 12.728 15.085
TEA 134217728 12.799 10.001
SAFER (r=8) 67108864 10.565 6.058
GOST 134217728 12.829 9.977
SHARK (r=6) 268435456 12.878 19.879
CAST-128 134217728 7.090 18.054
CAST-256 134217728 9.995 12.806
Square 268435456 7.801 32.816
SKIPJACK 67108864 12.017 5.326
RC6 268435456 7.871 32.524
MARS 268435456 8.503 30.107
Rijndael 268435456 8.442 30.325
Twofish 268435456 9.974 25.667
Serpent 134217728 10.505 12.185
ARC4 536870912 8.122 63.039
SEAL 1073741824 8.672 118.081
WAKE 1073741824 13.029 78.594
Panama Cipher (little endian) 1073741824 8.512 120.301
Panama Cipher (big endian) 536870912 7.091 72.204
Sapphire 134217728 12.868 9.947
MD5-MAC 1073741824 12.078 84.782
XMACC/MD5 1073741824 11.096 92.286
HMAC/MD5 1073741824 10.254 99.863
CBC-MAC/RC6 268435456 8.713 29.381
DMAC/RC6 268435456 8.642 29.623
BlumBlumShub 512 524288 10.766 0.046
BlumBlumShub 1024 262144 12.668 0.020
BlumBlumShub 2048 65536 8.903 0.007

[Oct 20, 2002] Cryptographic Algorithms

discussion of several popular algorithms

[Aug 3, 2002] Useful links

O'Reilly Java Center -- News -- An Interview with Jonathan Knudsen

Java Cryptography -- Sample chapter Authentication

The first challenge of building a secure application is authentication. Let's look at some examples of authentication from everyday life:

Authentication is tremendously important in computer applications. The program or person you communicate with may be in the next room or on another continent; you have none of the usual visual or aural clues that are helpful in everyday transactions. Public key cryptography offers some powerful tools for proving identity.

In this chapter, I'll describe three cryptographic concepts that are useful for authentication:

A common feature of applications, especially custom-developed "enterprise" applications, is a login window. Users have to authenticate themselves to the application before they use it. In this chapter, we'll examine several ways to implement this with cryptography.[1] In the next section, for instance, I'll show two ways to use a message digest to avoid transmitting a password in cleartext from a client to a server. Later on, we'll use digital signatures instead of passwords.

Index of -~timtas-aes

aesutil 1.0.1 (Stable)
by Tim Tassonis - Friday, July 19th 2002 13:20 EDT

About: aesutil is a small library and command line program to encrypt or decrypt data using the Rijndael algorithm in CBC mode.

Changes: A Windows port of the commandline utility, and better option handling.

Recommended Links

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The Rijndael Page -- new standard cypher.



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Encryption and Security Tutorial

Certicom - Online Tutorial

Welcome to the Elliptic Curve Cryptosystem Classroom. This site provides an intuitive introduction to Elliptic Curves and how they are used to create a secure and powerful cryptosystem. The first three sections introduce and explain the properties of elliptic curves. A background understanding of abstract algebra is required, much of which can be found in the Background Algebra section. The next section describes the factor that makes elliptic curve groups suitable for a cryptosystem though the introduction of the Elliptic Curve Discrete Logarithm Problem (ECDLP). The last section brings the theory together and explains how elliptic curves and the ECDLP are applied in an encryption scheme. This classroom requires a JAVA enabled browser for the interactive elliptic curve experiments and animated examples.

Elliptic curves as algebraic/geometric entities have been studied extensively for the past 150 years, and from these studies has emerged a rich and deep theory. Elliptic curve systems as applied to cryptography were first proposed in 1985 independently by Neal Koblitz from the University of Washington, and Victor Miller, who was then at IBM, Yorktown Heights.

Many cryptosystems often require the use of algebraic groups. Elliptic curves may be used to form elliptic curve groups. A group is a set of elements with custom-defined arithmetic operations on those elements. For elliptic curve groups, these specific operations are defined geometrically. By introducing more stringent properties to the elements of a group, such as limiting the number of points on such a curve, creates an underlying field for an elliptic curve group. In this classroom, elliptic curves are first examined over real numbers in order to illustrate the geometrical properties of elliptic curve groups. Thereafter, elliptic curves groups are examined with the underlying fields of Fp (where p is a prime) and F2m (a binary representation with 2m elements).

Quantum Cryptography Tutorial

Cryptography for encryption, signatures and authentication

Cryptography -- mainly PGP related...



Recommended Papers

Number theory

Prime Numbers - University of Tennessee


Block encryption



SSH - Tech Corner - Cryptographic Algorithms

Lecture Notes

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The Mandala Centre - Compression and Security - One on one compression FAQ

University Courses

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Lectures for Computer Security

These lectures contain the base introductory material used for this course. After these lectures, the student will be familiar with the underlying concepts of advanced operating systems.

Crypto Lectures



See also Humor

My boss asked me for a letter describing my partner Bob Smith, and this is what I wrote:

Bob Smith, my assistant programmer, can always be found

hard at work in his cubicle. Bob works independently, without

wasting company time talking to colleagues. Bob never

thinks twice about assisting fellow employees, and he always

finishes given assignments on time. Often Bob takes extended

measures to complete his work, sometimes skipping

coffee breaks. Bob is a dedicated individual who has absolutely no

vanity in spite of his high accomplishments and profound

knowledge in his field. I firmly believe that Bob can

be classed as a high-caliber employee, the type which cannot

be dispensed with. Consequently, I duly recommend that Bob

be promoted to executive management, and a proposal will

be executed as soon as possible.

S.D. - Project Leader

Shortly afterward I sent the following follow-up note: That bastard Bob was reading over my shoulder while I wrote the report sent to you earlier today. Kindly read only the odd numbered lines (1, 3, 5, etc.) for my true assessment. Regards,




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The Last but not Least Technology is dominated by two types of people: those who understand what they do not manage and those who manage what they do not understand ~Archibald Putt. Ph.D

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Last modified: May 27, 2018