Dan Jones writes "2009 marks 60 years since the advent of modern cryptography. It was back in October 1949 when mathematician Claude Shannon published a paper on Communication Theory of Secrecy Systems. According to his employer at the time, Bell Labs, the work transformed cryptography from an art to a science and is generally considered the foundation of modern cryptography. Since then significant developments in secure communications have continued, particularly with the advent of the Internet and Web. CIO has a pictorial representation of the past six decades of research and development in encryption technology. Highlights include the design of the first quantum cryptography protocol by Charles Bennett and Gilles Brassard in 1984, and the EFF's 'Deep Crack' DES code breaker of 1998."
I have developed my own uncrackable form of encryption, the only downside being that it takes a long time. The process basically involves saving my data to a Linux filesystem, and then waiting until the OS inevitably corrupts itself beyond compare. Hey presto, encrypted data!
Fair question. I think it was the application of numerical theory, the idea that if you treated characters as numbers that you could encrypt them with math.
Your post is a great example of pre-modern crypto.
Well, all slashdot readers have probably read The Code Book [simonsingh.net] by Simon Singh years ago. No article is needed at this point, nothing new here.
Rejewski made in December 1932, according to historian David Kahn, one of the greatest advances in cryptologic history by applying pure mathematics group theory to breaking the German armed forces' Enigma machine ciphers.
BTW, since most of you are unlikely to read the whole wiki article, there's one very amusing part...;p
On September 17, as the Soviet Army invaded Poland, Cipher Bureau personnel crossed the southeastern border with other Polish military and government personnel, into Romania. They eventually made their way to France where, at "PC Bruno", outside Paris, they continued breaking German Enigma traffic in collaboration with Bletchley Park, fifty miles northwest of London, England. In the interest of security, the allied cryptological services, before sending their messages over a teletype line, encrypted them using Enigma doubles. Henri Braquenié often closed messages with a "Heil Hitler!"
Exactly what I thought. I don't know how the Enigma was developed but it was a very sound device, and there are still messages that we can not decypher. Even having one in your hands didn't help much if you don't know the settings.
But then this feels like a pretty much US centric article, only looking at cryptographic advances in the US (admittedly most comes from there - but the article lists exclusively US achievements).
Germany was certainly very advanced cryptographically with their Enigma machine. Unf
> Unfortunately this machine ended up on the losing side of the war, so a lot of the > knowledge will have been lost thanks to that.
Er, the German guy who invented the Enigma was killed in a horse carriage accident in 1929. So, no, the war had no direct effect on cryptographic knowledge in the way you imply. Considering the enormous number of casualties on both sides, however, I'm sure it affected it in a general way.
I've recently become rather fascinated by the Enigma machine and the operation of the device. The Wikipedia [wikipedia.org] article is worth a read.
Couple of cool things to know about the Enigma:
I believe it was the first machine to have symmetrical encoding and decoding. Because it had a this property (as a letter was coded through the rotors, there was a rotor that reflected the encoding back through the rotor stages again), an operator could code and decode messages without reconfiguring the device.
I believe it was the first machine to have symmetrical encoding and decoding. Because it had a this property (as a letter was coded through the rotors, there was a rotor that reflected the encoding back through the rotor stages again), an operator could code and decode messages without reconfiguring the device.
Due to the fact above, the Enigma could never encode a letter onto itself. This greatly decreased the permutations allowed and made the device less effective.
I may be misunderstanding your cause and effect combination slightly here, but the symmertical encoding/decoding did not cause Engima to never encode a letter onto itself; that was specifically because of the reflector cog at the end of the wheels and the design of the electrical circuit within the machine.
Operators would encode the rotor setup in the message.
Twice (in case there were problems in receiving the messages); this led to the British and Polish (who never get enough public credit, IMO) knowing, for example, that if the message started 'ABCDEF', then
The Enigma was one of the most advanced pre-modern cryptosystems. But it still treated letters as letters. To get to the next level, the separation of data (letters) from encryption into math operations was needed. This happened in parallel with the development of digital computers. Really, many of those advancements came from cryptanalysis of Enigma itself.
No the Enigma machine was not a cryptographically sound device. It's major technical flaw was that it would never substitute a letter for itself thanks to the way its circuitry worked.
How come history is written so that "Modern Cryptography" starts when an American writes a paper, some seven years after the British have developed computers to automatically crack Germany's enigma codes? Modern cryptography isn't just the creation of the cipher, but the appreciation of modern techniques to crack it.
If this article can make such an arbitrary assumption about what is modern, I give little credit to how misinformed the rest of the article may be. It's how Americans steal history, so they can define it in their own favor.
I do not mean to flame. I am just skeptical of assumptions, when such a basic assumption is so inherently wrong.
The British came up with public key encryption [nytimes.com] well before Diffie & Hellman but since the work was for the secret service it was all highly classified. The work belonged to the government and couldn't be patented for profit as RSA has been. Bit hard to be part of history if it's all totally hush hush.
Can't remember where I heard this, some Discovery channel programme probably, but the guy that did a lot of the work wasn't allowed to take anything out of the secure building he worked in and nor was he allowed to write anything down so alledgedly did all his mathematical work in his head. Bit hard to believe really but not that implausible.
Don't blame the US. This is a bit of special pleading for Bell Labs, where Shannon worked.
In fact, as is well known, A M Turing worked at Bell for a short time during WW2. He also learnt at Princeton the electronics that made the Bombes possible.
Modern cryptanalysis was a US/UK cooperation with information and development coming from both sides The Poles obtained an Enigma and started the mathematical theory of decrypting Enigma messages: the analysts at Bletchley, of whom Turing was only one (remember I J Good, anybody?) too it forward, and then post-Pearl Harbor it became (at least in part) a joint venture. It isn't necessary for the US to pretend that they did it all by themselves; we associate that kind of insecurity with the Soviet Union.
The (US) guy who recently wrote a history of D-Day (sorry, forget his name) writes somewhere that while the perception that in WW2 the British had the ideas and the US provided the productive capacity is not really correct as it stands, there is some truth in it. That should really be good enough for everybody.
It's how Americans steal history, so they can define it in their own favor.
No, it's how academics think nobody else can do anything right because they're smarter. You can be doing state of the art work with a sound foundation, but until some PhD comes along and "formalizes" what you're doing, you're just a hacker.
"While the British worked on code breaking, and some of what was discovered there applies to modern code breaking, they didn't work on modern coding techniques. Their concern was breaking the codes of the day, understandably."
Oh right, so conveniently the 1940s don't count as "modern" , but the 1950s do? What a crock of shit. Talk about modifiying meanings to suit your own ends. The german codes were created using a machine and on the british side were partly decoded using electronic computers. If that doesn't count as modern then I don't know what does.
In the 1940s, the British were no further along in designing codes than the Germans. Both used ingenious versions of the old letter substitution algorithm. Shannon's paper and the advent of digital computers were a watershed in code design. That the British used electronic computers to break German codes is entirely beside the point. It's not a coincidence the headline talks about 'cryptography' and not the art of reading or breaking codes, i.e. cryptanalysis.
As I noted above "It isn't necessary for the US to pretend that they did it all by themselves; we associate that kind of insecurity with the Soviet Union."
There is not a "massive divide". A growing body of knowledge got formalised into a useful structure. We don't say modern physics began with Newton, Einstein or Planck. We recognise a continuum. Modern cryptography clearly began in the 1930s when people started formulating mechanical means of encryption and decryption, advanced when mechanical means of cod
At the time you had to go through a gate with armed military types then make your way around to the museum parking lot. Once inside, I remembered that I had forgotten to lock my car doors, and mentioned to the guard that I was going to go back out to the parking lot to do this. He looked at me and said, "Don't worry about it, your car is being watched".
In any case, I highly recommend visiting this museum if you are a geek type. from a real Enigma that you can touch, to a Cray II that you can sit on, this place is cryptogeek heaven. A truly interesting experience.
A stupid question you might think , but unless you know what the output should be , how do you know when you've found it? Unless a computer knows every language on the planet and "reads" ever version of the potential output and decides if it makes sense how can it ever know when the decryption is finished? And what if its not plain text its decrypting but something else entirely such as a binary file? Perhaps I'm just dumb but this is something I've never understodd.
Decryption is a mathematical operation. You are given a blob of yunk. You can be fairly certain it is encrypted with a given cipher because it meets certain characteristics - either length, or hash-depth, or there is a header or footer of a given length, or some revealing information about the cipher may have been sent prior to or alongside the encrypted blob.
Then, if you're smart enough, or you have enough money, or time, or computing power, or a lot of luck, the decryption operation might occur. You can check as to whether or not you've successfully decrypted the data mathematically - e.g. does the result set fit with the function I've just run and give me the source data I started with? If so, yes, you've decrypted the data.
It's your responsibility as a researcher to decide what to do with whatever came out the other side. You may have to decrypt it again before proceeding. You may find out that what you just decrypted was nothing more sinister than ICMP_FRAGMENTATION_REQUIRED (Frak!).
The holy grail of cryptography may infact be steganographical encryption - or binary / machine language that reads as Grandmother's Cookie Recipe, but when run as an executable it actually glasses the machine. Who knows?
Sigh, who ever used this terminology? Do you really call character terminals glass terminals? None of my computers involve any glass any more; if they do it's quartz glass in an EPROM, and I sincerely doubt I even have anything with a real EPROM in it any more:P
Fair enough , but what if something has been encrypted twice? You've successfully decrypted the 2nd stage but the output is still statistically noise because its still encrypted by the 1st encryption stage. How would you solve this problem?
"Encrypted twice" doesn't mean anything. A composed encryption scheme is a single function, same as y = (2x + 1)^2 - 4.
As stated below, steganography is the stopping problem here. Is the secret meaning hidden in typos and word order, or do the words have a second meaning?
What the parent means is that if you have two encryption functions, f1(x) and f2(x) then applying f1 and then f2 to your message is the same as applying a third encryption function f3, where f3(x)=f2(f1(x)). You can just apply cryptanalysis techniques to f3 to determine x, without needing to determine the intermediate message f1(x).
While f3(x) may well be stronger than f1(x) or f2(x), this is not necessarily the case.
"Encrypted twice" doesn't mean anything. A composed encryption scheme is a single function, same as y = (2x + 1)^2 - 4.
Technically true, but depending on the cipher(s) you use, you may have no idea at all what the resulting function is, and it is therefore often easier to decrypt in the same steps you used for the encryption.
Some cryptographic functions, RSA for instance, are mathematical groups. In other words, RSA(RSA(plaintext, key1), key2) === RSA(plaintext, key3) for some key3 that you probably don't know. In such cases, if you were trying to break the cipher and had no means to recover keys 1 and 2, it would be easi
CIO has a pictorial representation of the past six decades of research and development in encryption technology.
And every [wikipedia.org], single [wikipedia.org], image [wikipedia.org] in that slide show is ripped directly from Wikipedia. In fact, the entire presentation is little more that a digest of someones Wikitrip.
As Paul Graham(I think) said, "Pay to view content on the internet may as well not exist". Given that information not on the internet is becoming increasingly obsolete, this maxim can be extended to the conclusion that; the only content that will matter is that which is freely available online. People such as journalists or even reviewing researchers are not going to go to the hassle of chasing down sources closeted in dusty libraries or the like, when low hanging fruit such as Wikipedia pages are so easily accessible.
There was a story a few weeks ago about how a copyright black hole [ft.com] is swallowing our culture. Well, it's swallowing more than that. It's swallowing cold hard facts, data, progress and information too. Compound this easily accessible and digestible, though lower quality, alternatives available online at places like Wikipedia, and you are seeing the beginning of a major shift in how our society comes by its information and the truth itself.
For over 5 months Wikipedia had an incorrect start date for World War 2 [wikipedia.org]. In the new information regime that is emerging, for a great many (mostly younger) people, for those 5 months, that became the start date for World War 2. The (old) correct date was cloistered away in libraries and pay per view papers or books. The new date was the first hit on a Google search. Which is more likely to become the dominant interpretation?
We have seen it time and again. Cheaper and easier will win out over expensive and difficult. The same is now happening for information. This doesn't necessarily mean that cheap and easy has to be worse, but in the case of finding cold hard facts online, it is. There is no quality control on the internet hive mind [jonathancrossfield.com]. The online or Wikipedia version of the truth is becoming the dominant one, and with the black hole swallowing all the hard facts, how will we ever find the real truth again?
Orwell was right about the outcome, but wrong about the method. You don't need to hide the truth. You just need to make the alternatives easier to find.
Wait, somebody uses "The late 1930s" in place of "September 3, 1939" and this supports your argument that somehow truth is being obscured?
I can see complaining if the date went from specific to general to generally incorrect, but this example is manifestly the reverse of that. Seems like truth is getting easier to find, doesn't it?
The "Late 1930's" date was up on the page from the 8th of March to the 17th of July last year. That's a long time for the page to be wrong. Consider what the first result for "World War 2" was for that period. How many people read that article to find out things like the start date.
My point here is that while the correct start date is well known, an incorrect date was the easiest one to find. Sure, this is an easy case and you can complain about lazy researchers. But when things get more complicated than th
I'm assuming you mean that WWII did not start until Japan's attack on the USA? Well - the views differ. I've been through school long before Wikipedia existed (or was even considered), and all my history books talk about September 1939. I'm not going to claim to know what "historians" think of the matter - other than that they probably disagree, and that you're likely to see one opinion more strongly represented on either side of the Atlantic Ocean.
There are numerous possible starting dates for WWII.
In 1937, Japan attacked China, and this war was the first of the ones that merged to form WWII. It's a legitimate start date.
September 1939 is popular, either September 1 after which Germany was always at war, or September 3 when Britain and France declared war.
Of course, this was still a much smaller war than WWI, and it consisted of occasional campaigns united only by British resistance. We have a comparable situation in the early 19th Century,
I'd say that Auguste Kerckhoffs is the father of modern cryptography. Kerckhoffs' principle is essentially the same as Shannon's maxim but he formulated it 70 years earlier.
1. Set up an arbitrary point in time. (E.g. "the advent of modern cryptography", or "the invention of X by NotActualInventorY"R 2. Create an article, celebrating the X years since then. 3. Write up a crappy "history". (The crappier, the more "controversy" [aka. "troll power"] it will create.) 4.... 5. PROFIT!
Not shaministic - its called requirements analysis.
Take customer/manager, listen to their random and usually contradictory utterances and rearrange into something approaching a set of system requirements.
You, apparently, didn't buy the key to the book. The actual story that is revealed is a knee slapping, edge of seat read that will make you laugh, cry, slap your mamma. Oh, and it has all the stuff you really wanted. Next time you buy a book on cryptography, turn it 90 degrees, read back to front, right to left, every other character on odd pages that aren't prime, every fourth letter on even pages that don't end in zero. Once you've collected the letters, use the ISBN as a skip guide to pull letters off of
If you are looking for a good "quick primer" on cryptography and cryptanalysis through recent history, Simon Singh's "Code Book" is a good read.
He talks about the people involved (what they were hiding, or why they wanted stuff unhiding) as much as the techniques in places and covers related areas like deciphering ancient languages - this helps the uninitiated reader develop a sense of how it all fits in with the rest of life and makes the book far less dry than other books with a similar goals.
Hooray! (Score:2, Insightful)
Uncrackable encryption (Score:2, Funny)
I have developed my own uncrackable form of encryption, the only downside being that it takes a long time. The process basically involves saving my data to a Linux filesystem, and then waiting until the OS inevitably corrupts itself beyond compare. Hey presto, encrypted data!
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?yhpargotpyrc nredom-erp dna yhpargotpyrc nredom neewteb ecnereffid eht si tahW
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For those who aren't cryptographers: that message decrypts as "First Post!"
Can we have an article please? (Score:2)
Ad-laden slideshows are not my favorite sources of information.
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Well, all slashdot readers have probably read The Code Book [simonsingh.net] by Simon Singh years ago. No article is needed at this point, nothing new here.
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Ad-laden slideshows...
Is he Bin-laden's cousin?
Caesar (Score:2, Interesting)
Re:Caesar (Score:5, Informative)
Though that might had happened earlier than the summary suggests...from http://en.wikipedia.org/wiki/Biuro_Szyfrow#Enigma_solved [wikipedia.org] :
Rejewski made in December 1932, according to historian David Kahn, one of the greatest advances in cryptologic history by applying pure mathematics group theory to breaking the German armed forces' Enigma machine ciphers.
BTW, since most of you are unlikely to read the whole wiki article, there's one very amusing part... ;p
On September 17, as the Soviet Army invaded Poland, Cipher Bureau personnel crossed the southeastern border with other Polish military and government personnel, into Romania. They eventually made their way to France where, at "PC Bruno", outside Paris, they continued breaking German Enigma traffic in collaboration with Bletchley Park, fifty miles northwest of London, England. In the interest of security, the allied cryptological services, before sending their messages over a teletype line, encrypted them using Enigma doubles. Henri Braquenié often closed messages with a "Heil Hitler!"
Parent
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Exactly what I thought. I don't know how the Enigma was developed but it was a very sound device, and there are still messages that we can not decypher. Even having one in your hands didn't help much if you don't know the settings.
But then this feels like a pretty much US centric article, only looking at cryptographic advances in the US (admittedly most comes from there - but the article lists exclusively US achievements).
Germany was certainly very advanced cryptographically with their Enigma machine. Unf
What? (Score:3, Informative)
> Unfortunately this machine ended up on the losing side of the war, so a lot of the
> knowledge will have been lost thanks to that.
Er, the German guy who invented the Enigma was killed in a horse carriage accident in 1929. So, no, the war had no direct effect on cryptographic knowledge in the way you imply. Considering the enormous number of casualties on both sides, however, I'm sure it affected it in a general way.
Cool Enigma Facts (Score:3, Informative)
Couple of cool things to know about the Enigma:
I believe it was the first machine to have symmetrical encoding and decoding. Because it had a this property (as a letter was coded through the rotors, there was a rotor that reflected the encoding back through the rotor stages again), an operator could code and decode messages without reconfiguring the device.
Due to the
Re: (Score:2, Informative)
I believe it was the first machine to have symmetrical encoding and decoding. Because it had a this property (as a letter was coded through the rotors, there was a rotor that reflected the encoding back through the rotor stages again), an operator could code and decode messages without reconfiguring the device. Due to the fact above, the Enigma could never encode a letter onto itself. This greatly decreased the permutations allowed and made the device less effective.
I may be misunderstanding your cause and effect combination slightly here, but the symmertical encoding/decoding did not cause Engima to never encode a letter onto itself; that was specifically because of the reflector cog at the end of the wheels and the design of the electrical circuit within the machine.
Operators would encode the rotor setup in the message.
Twice (in case there were problems in receiving the messages); this led to the British and Polish (who never get enough public credit, IMO) knowing, for example, that if the message started 'ABCDEF', then
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No the Enigma machine was not a cryptographically sound device. It's major technical flaw was that it would never substitute a letter for itself thanks to the way its circuitry worked.
Mention of Enigma (Score:5, Insightful)
But none of Alan Turing.
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That's SO gay.
How come? (Score:5, Insightful)
How come history is written so that "Modern Cryptography" starts when an American writes a paper, some seven years after the British have developed computers to automatically crack Germany's enigma codes? Modern cryptography isn't just the creation of the cipher, but the appreciation of modern techniques to crack it.
If this article can make such an arbitrary assumption about what is modern, I give little credit to how misinformed the rest of the article may be. It's how Americans steal history, so they can define it in their own favor.
I do not mean to flame. I am just skeptical of assumptions, when such a basic assumption is so inherently wrong.
Re:How come? (Score:5, Informative)
The British came up with public key encryption [nytimes.com] well before Diffie & Hellman but since the work was for the secret service it was all highly classified. The work belonged to the government and couldn't be patented for profit as RSA has been. Bit hard to be part of history if it's all totally hush hush.
Can't remember where I heard this, some Discovery channel programme probably, but the guy that did a lot of the work wasn't allowed to take anything out of the secure building he worked in and nor was he allowed to write anything down so alledgedly did all his mathematical work in his head. Bit hard to believe really but not that implausible.
Parent
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Bell labs (Score:4, Informative)
In fact, as is well known, A M Turing worked at Bell for a short time during WW2. He also learnt at Princeton the electronics that made the Bombes possible.
Modern cryptanalysis was a US/UK cooperation with information and development coming from both sides The Poles obtained an Enigma and started the mathematical theory of decrypting Enigma messages: the analysts at Bletchley, of whom Turing was only one (remember I J Good, anybody?) too it forward, and then post-Pearl Harbor it became (at least in part) a joint venture. It isn't necessary for the US to pretend that they did it all by themselves; we associate that kind of insecurity with the Soviet Union.
The (US) guy who recently wrote a history of D-Day (sorry, forget his name) writes somewhere that while the perception that in WW2 the British had the ideas and the US provided the productive capacity is not really correct as it stands, there is some truth in it. That should really be good enough for everybody.
Parent
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It isn't necessary for the US to pretend that they did it all by themselves; we associate that kind of insecurity with the Soviet Union.
The rest of the world associates it with Hollywood.
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No, it's how academics think nobody else can do anything right because they're smarter. You can be doing state of the art work with a sound foundation, but until some PhD comes along and "formalizes" what you're doing, you're just a hacker.
Answer in the summary (Score:2)
"According to his employer at the time, Bell Labs"
Hmm. What could be less biased than a company writing a press release about its own achievements?
Next you'll be telling us that the press releases about Segways reinventing personal transportation might not be entirely accurate.
Wtf? (Score:4, Insightful)
"While the British worked on code breaking, and some of what was discovered there applies to modern code breaking, they didn't work on modern coding techniques. Their concern was breaking the codes of the day, understandably."
Oh right, so conveniently the 1940s don't count as "modern" , but the 1950s do? What a crock of shit. Talk about modifiying meanings to suit your own ends. The german codes were created using a machine and on the british side were partly decoded using electronic computers. If that doesn't count as modern then I don't know what does.
Parent
Re:Wtf? (Score:4, Insightful)
In the 1940s, the British were no further along in designing codes than the Germans. Both used ingenious versions of the old letter substitution algorithm. Shannon's paper and the advent of digital computers were a watershed in code design.
That the British used electronic computers to break German codes is entirely beside the point. It's not a coincidence the headline talks about 'cryptography' and not the art of reading or breaking codes, i.e. cryptanalysis.
Parent
Don't be ridiculous (Score:2)
There is not a "massive divide". A growing body of knowledge got formalised into a useful structure. We don't say modern physics began with Newton, Einstein or Planck. We recognise a continuum. Modern cryptography clearly began in the 1930s when people started formulating mechanical means of encryption and decryption, advanced when mechanical means of cod
Naaaahh.... (Score:3, Interesting)
A funny side note. (Score:5, Interesting)
Several years ago I visited the National Cryptologic Museum at Ft Meade MD. http://www.nsa.gov/about/cryptologic_heritage/museum/ [nsa.gov]
At the time you had to go through a gate with armed military types then make your way around to the museum parking lot. Once inside, I remembered that I had forgotten to lock my car doors, and mentioned to the guard that I was going to go back out to the parking lot to do this. He looked at me and said, "Don't worry about it, your car is being watched".
In any case, I highly recommend visiting this museum if you are a geek type. from a real Enigma that you can touch, to a Cray II that you can sit on, this place is cryptogeek heaven. A truly interesting experience.
How do you know when you've decrypted something? (Score:4, Interesting)
A stupid question you might think , but unless you know what the output should be , how do you know when you've found it? Unless a computer knows every language on the planet and "reads" ever version of the potential output and decides if it makes sense how can it ever know when the decryption is finished? And what if its not plain text its decrypting but something else entirely such as a binary file? Perhaps I'm just dumb but this is something I've never understodd.
Re:How do you know when you've decrypted something (Score:5, Informative)
Decryption is a mathematical operation. You are given a blob of yunk. You can be fairly certain it is encrypted with a given cipher because it meets certain characteristics - either length, or hash-depth, or there is a header or footer of a given length, or some revealing information about the cipher may have been sent prior to or alongside the encrypted blob.
Then, if you're smart enough, or you have enough money, or time, or computing power, or a lot of luck, the decryption operation might occur. You can check as to whether or not you've successfully decrypted the data mathematically - e.g. does the result set fit with the function I've just run and give me the source data I started with? If so, yes, you've decrypted the data.
It's your responsibility as a researcher to decide what to do with whatever came out the other side. You may have to decrypt it again before proceeding. You may find out that what you just decrypted was nothing more sinister than ICMP_FRAGMENTATION_REQUIRED (Frak!).
The holy grail of cryptography may infact be steganographical encryption - or binary / machine language that reads as Grandmother's Cookie Recipe, but when run as an executable it actually glasses the machine. Who knows?
Parent
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it actually glasses the machine.
Sigh, who ever used this terminology? Do you really call character terminals glass terminals? None of my computers involve any glass any more; if they do it's quartz glass in an EPROM, and I sincerely doubt I even have anything with a real EPROM in it any more :P
Re:How do you know when you've decrypted something (Score:4, Interesting)
Fair enough , but what if something has been encrypted twice? You've successfully decrypted the 2nd stage but the output is still statistically noise because its still encrypted by the 1st encryption stage. How would you solve this problem?
Parent
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"Encrypted twice" doesn't mean anything. A composed encryption scheme is a single function, same as y = (2x + 1)^2 - 4.
As stated below, steganography is the stopping problem here. Is the secret meaning hidden in typos and word order, or do the words have a second meaning?
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You could encrypt with one algorithm, then take the output from that and encrypt again with a completely different one.
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While f3(x) may well be stronger than f1(x) or f2(x), this is not necessarily the case.
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"Encrypted twice" doesn't mean anything. A composed encryption scheme is a single function, same as y = (2x + 1)^2 - 4.
Technically true, but depending on the cipher(s) you use, you may have no idea at all what the resulting function is, and it is therefore often easier to decrypt in the same steps you used for the encryption.
Some cryptographic functions, RSA for instance, are mathematical groups. In other words, RSA(RSA(plaintext, key1), key2) === RSA(plaintext, key3) for some key3 that you probably don't know. In such cases, if you were trying to break the cipher and had no means to recover keys 1 and 2, it would be easi
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If something is encrypted twice with two different keys, what you actually have is a new crypto algorithm with a longer key. See:
cryptoA(keyA, plaintext) = ciphertext
cryptoB(keyB, plaintext) = ciphertext
So you propose doing
cryptoA(keyA, cryptoB(keyB, plaintext)) = ciphertext
This could be rewritten as cryptoC(keyA+keyB, plaintext) = ciphertext
With Thanks to Wikimedia (Score:3, Insightful)
And every [wikipedia.org], single [wikipedia.org], image [wikipedia.org] in that slide show is ripped directly from Wikipedia. In fact, the entire presentation is little more that a digest of someones Wikitrip.
As Paul Graham(I think) said, "Pay to view content on the internet may as well not exist". Given that information not on the internet is becoming increasingly obsolete, this maxim can be extended to the conclusion that; the only content that will matter is that which is freely available online. People such as journalists or even reviewing researchers are not going to go to the hassle of chasing down sources closeted in dusty libraries or the like, when low hanging fruit such as Wikipedia pages are so easily accessible.
There was a story a few weeks ago about how a copyright black hole [ft.com] is swallowing our culture. Well, it's swallowing more than that. It's swallowing cold hard facts, data, progress and information too. Compound this easily accessible and digestible, though lower quality, alternatives available online at places like Wikipedia, and you are seeing the beginning of a major shift in how our society comes by its information and the truth itself.
For over 5 months Wikipedia had an incorrect start date for World War 2 [wikipedia.org]. In the new information regime that is emerging, for a great many (mostly younger) people, for those 5 months, that became the start date for World War 2. The (old) correct date was cloistered away in libraries and pay per view papers or books. The new date was the first hit on a Google search. Which is more likely to become the dominant interpretation?
We have seen it time and again. Cheaper and easier will win out over expensive and difficult. The same is now happening for information. This doesn't necessarily mean that cheap and easy has to be worse, but in the case of finding cold hard facts online, it is. There is no quality control on the internet hive mind [jonathancrossfield.com]. The online or Wikipedia version of the truth is becoming the dominant one, and with the black hole swallowing all the hard facts, how will we ever find the real truth again?
Orwell was right about the outcome, but wrong about the method. You don't need to hide the truth. You just need to make the alternatives easier to find.
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I can see complaining if the date went from specific to general to generally incorrect, but this example is manifestly the reverse of that. Seems like truth is getting easier to find, doesn't it?
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The "Late 1930's" date was up on the page from the 8th of March to the 17th of July last year. That's a long time for the page to be wrong. Consider what the first result for "World War 2" was for that period. How many people read that article to find out things like the start date.
My point here is that while the correct start date is well known, an incorrect date was the easiest one to find. Sure, this is an easy case and you can complain about lazy researchers. But when things get more complicated than th
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I'm assuming you mean that WWII did not start until Japan's attack on the USA?
Well - the views differ. I've been through school long before Wikipedia existed (or was even considered), and all my history books talk about September 1939. I'm not going to claim to know what "historians" think of the matter - other than that they probably disagree, and that you're likely to see one opinion more strongly represented on either side of the Atlantic Ocean.
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There are numerous possible starting dates for WWII.
In 1937, Japan attacked China, and this war was the first of the ones that merged to form WWII. It's a legitimate start date.
September 1939 is popular, either September 1 after which Germany was always at war, or September 3 when Britain and France declared war.
Of course, this was still a much smaller war than WWI, and it consisted of occasional campaigns united only by British resistance. We have a comparable situation in the early 19th Century,
What about Auguste Kerckhoffs? (Score:2)
I'd say that Auguste Kerckhoffs is the father of modern cryptography. Kerckhoffs' principle is essentially the same as Shannon's maxim but he formulated it 70 years earlier.
New pointless article scheme: (Score:2)
1. Set up an arbitrary point in time. (E.g. "the advent of modern cryptography", or "the invention of X by NotActualInventorY"R ...
2. Create an article, celebrating the X years since then.
3. Write up a crappy "history". (The crappier, the more "controversy" [aka. "troll power"] it will create.)
4.
5. PROFIT!
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Not shaministic - its called requirements analysis.
Take customer/manager, listen to their random and usually contradictory utterances and rearrange into something approaching a set of system requirements.
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If you are looking for a good "quick primer" on cryptography and cryptanalysis through recent history, Simon Singh's "Code Book" is a good read.
He talks about the people involved (what they were hiding, or why they wanted stuff unhiding) as much as the techniques in places and covers related areas like deciphering ancient languages - this helps the uninitiated reader develop a sense of how it all fits in with the rest of life and makes the book far less dry than other books with a similar goals.
There is an