We’re rewarding the question askers & reputations are being recalculated! Read more.

Questions tagged [history]

History of cryptography and cryptanalysis. Questions that wish to ask about the history of cryptography should use this tag; if you're asking about historical ciphers you may also wish to use the classical-cipher tag.

Filter by
Sorted by
Tagged with
0
votes
1answer
51 views

Side-channel attack in the real wold [duplicate]

I have a big problem to figure how the security model in papers about side-channel are relevant (briefly the attacker has a partial access to the hardware). Why these breaches are so seriously ...
1
vote
0answers
40 views

Are there official test vectors for historic ciphers? [closed]

In many cases when cryptographic algorithms are published the paper also provides a set of test vectors that can be used by developers to verify their implementations. For historic ciphers such as ...
2
votes
4answers
315 views

Academic breach revealed too late

Do you know if is has already happened (since 1980), that someone (academic or not) has "broken" (even in a weak sense) some cryptographic assumption, but has chosen to not first publish and directly ...
2
votes
1answer
146 views

Could public-key crypto be performed long ago if the idea had been discovered?

Public-key cryptography was not invented until the 1970's. Apart from the idea not existing earlier (as talked about here), is there any reason it could not have been used earlier? For example, are ...
3
votes
3answers
234 views

Most secure but feasible encryption running on WWII technology

Imagine you are transported back to ~1940. What is the best (i.e. most secure, but technologically feasible) encryption you can think of for widespread (i.e. military) use? How would you implement it?
3
votes
0answers
66 views

What was used for symmetric message authentication before HMAC was invented?

Currently, Carter Wegman MACs are popular. Before that, HMAC was popular. What was popular before HMAC? Was it CBC-MAC? Something else? I know about NIST FIPS 113 "Data Authentication Algorithm" ...
5
votes
10answers
605 views

Soft question: What are examples of beautiful proofs in cryptography? [closed]

These may include any proofs, reductions, constructions, etc. For example, simple solutions to problems which at first sight seem difficult. Elegant construction that hide deep mathematical concepts, ...
59
votes
6answers
9k views

Soft question: Examples where lack of mathematical rigour cause security breaches?

Cryptographic tools can often become adopted even when their security proofs lack mathematical rigour - or altogether missing. Are there famous cases of security breaches in the industry, where the ...
5
votes
0answers
92 views

What is the “brand X” cipher mentioned in the Usenet thread about RC4?

In the original Usenet thread about RC4 when it was finally reverse engineered, a user by the name of Michael Johnson mentioned that the RC4 algorithm looked surprisingly like another proprietary ...
5
votes
0answers
84 views

Why did Rabin use $x(x + b)$ instead of just $x^2$ in the original paper?

Encryption in the original Rabin scheme took a message $x$ and computed $x(x + b) \bmod n$, where $0 \le b \lt n$ and $n$ is the product of two secret primes $p$ and $q$. The private key is defined as ...
7
votes
0answers
115 views

What is the origin of the phrase “Don't roll your own crypto”?

The phrase is well-known and widely used, it is often attributed to Bruce Schneier and is indeed relevant to his Schneier's Law. However, I wasn't able to find this specific wording among Schneier's ...
2
votes
0answers
39 views

Difference in SKIPJACK algorithms

This is going back a ways... Schneier discusses SKIPJACK at Declassifying Skipjack. Schneier offers a link to a reference implementation at ftp://ftp.funet.fi/pub/crypt/cryptography/symmetric/skipjack ...
5
votes
2answers
114 views

Origin of values for “security margin”?

It seems that the acceptable "security margin" for ciphers is set to be between 25% and 30% as a target by designers, where this number represents the number of rounds that remain "unbroken" for a ...
5
votes
1answer
111 views

When was hash chain first used?

Hash linking is used to prove the integrity of a blockchain, or similar systems. When was that technique first used? I would guess it was early, maybe 1950s/1960s?
9
votes
4answers
2k views

80-bit collision resistance because of 80-bit x87 registers?

This is just a curious question, and it probably doesn't belong here anyway, and I'm just being bold asking it here. 80-bit used to be considered an adequate level of security, Skipjack and SHA1 ...
4
votes
2answers
117 views

How was the 5 digit random number in the VIC cipher generated?

Knowing that VIC was a "spy cipher" it is unlikely that the agents used a cryptographic device to genreate the 5 digit number but how did they do it?
5
votes
1answer
307 views

Why did MD4 replace MD2?

MD2 was a hash function based on swapping bytes in a state array permutation, much like the RC4 stream cipher, whereas MD4 was a novel construction. MD4 replaced MD2 despite the fact that MD4 is more ...
13
votes
2answers
735 views

What motivated the creation of RSA and ECDH?

Recently I've been learning about cryptography and so far I am loving it. However, there are some things I do not comprehend. As far as I know, RSA was published in 1979 while New Directions on ...
3
votes
0answers
117 views

Old French Cipher w/ Text Hidden In Drawing

I'm trying to find a cipher challenge I saw a few years back, it was an old drawing (I think 1800's or earlier) with clouds and stars on it and French text was hidden in the image. Does anyone happen ...
5
votes
1answer
951 views

In the RSA DES challenges, how did the contestants know they had found the right key considering they weren't given any plaintext?

If the contestants were given both the plaintext and ciphertext, it's straightforward. Just bruteforce all 56-bit keys until you find one that maps the given plaintext to the given ciphertext. But ...
2
votes
3answers
145 views

Enigma: a Question from WW2

I have seen in the Imitation Game that the Germans reset the Enigma at midnight sharp, and then they start messaging by sending the weather report in the morning. But the device made by Alan Turing, ...
4
votes
2answers
801 views

Is RSA inspired by Diffie Hellman?

I read a bit of A Method for Obtaining Digital Signatures and Public-Key Cryptosystems that introduced RSA in 1977, and, while learning the steps in RSA a few days ago, I noticed that they are similar ...
7
votes
1answer
356 views

Who said “32 round Rijndael” in the third AES Conference

This is a historical question. In the third AES Conference of NIST (AES3), April 13-14, 2000, New York, near the end of the conference, one representative for each of the last 5 candidates sit on a ...
5
votes
1answer
106 views

Cryptanalysis in the middle ages — publications

Are there any publications, articles or literature discussing cryptanalysis and crypt breaking techniques in the middle-ages? I have seen various manuals from the middle ages describing various types ...
8
votes
3answers
640 views

Where can I find a description of the SHA-0 hash algorithm?

Where can I find the description and or pseudocode for the SHA-0 hash algorithm? I am looking for something on these lines: HMAC RIPEMD. I have been implementing a few of those (HMAC, HOTP, TOTP and ...
10
votes
0answers
251 views

What was the BassOmatic cipher, and what made it so weak?

According to Wikipedia, this homebrew cipher was originally used in PGP, before Phil Zimmermann replaced it with IDEA. Supposedly, insecurities in the algorithm were pointed out to him, leading to ...
3
votes
1answer
404 views

ECDSA public key recovery is discovered by whom?

I'm looking for the history of the method (ECDSA public key recovery from signature). Where did this implementation first appear in (is it bitcoin?) and who discovered this method?
5
votes
0answers
131 views

aside from DES has the NSA ever strengthened algorithms?

When DES was originally developed, the NSA changed the s-boxes. For decades people thought that their changes introduced a backdoor but then it was discovered that their changes actually strengthened ...
73
votes
5answers
11k views

How come Public key cryptography wasn't discovered earlier?

I became interested in crypto lately and read about symmetric and public key crypto algorithms. I understand how crucial the discoveries of the 1970s like RSA, DES and DH were in advancing the ...
2
votes
1answer
51 views

Would it be possible to negotiate a key of 128 or 256 bits strength using Merkle puzzles?

One can be fascinated by the simplicity of the schemes created by Ralf Merkle; like the Merkle tree or his key negociation protocol over an insecure channel. Wikipedia has some material on "Merkle ...
3
votes
0answers
182 views

Why is XOR preferred over XNOR in cryptography? [duplicate]

The advantages and properties exhibited by XOR are also exhibited by XNOR, like the ones mentioned in many answers like this one Information is preserved. $c = a \oplus b$. One may recover $a = c \...
12
votes
2answers
4k views

Why did Histiaeus tattoo his slave's head?

The story is often told that Histiaeus tattooed a secret message on his slave's head, waited for his hair to grow back, then sent him off to Miletus. Why would he have done this? The story is usually ...
21
votes
1answer
2k views

What was the first hash and what problem was it supposed to solve?

Today's hashes have many uses. File integrity, verification of a secret without revealing the secret (i.e. passwords), hash maps, bloom filters, and probably a few more cases not immediately coming to ...
5
votes
1answer
148 views

Major Block Ciphers between DES and AES competitions

DES was announced as a standard in 1976. AES competition started in 1997 and Rijndael was selected as standard in 2000. What are major block ciphers and block cipher designs made/proposed from 1976 to ...
13
votes
2answers
531 views

How were one-time pads and keys historically generated?

In the 20th century, it was common for various intelligence agencies and military organizations to use ciphering machines and one-time pads. However, no source I've seen ever mentions the process of ...
6
votes
0answers
209 views

How did the cryptographers of Bletchley Park figured out the chi stream of the Lorenz cipher?

How did the Bletchy Park code breakers figured out the chi stream of the Lorenz cipher, that was obscured in the cipher text, which Britain code breakers eventually decoded. It's written in The ...
2
votes
1answer
79 views

How effective noise based voice encryption against attack?

In WWII the primary way of encrypting radio broadcasts was to have the broadcaster transmit a signal with noise added from record, while the receiver would have an identical copy of the record ...
0
votes
1answer
179 views

When was a RSA Private Key Introduced?

I'm doing some research into the RSA cryptosystem but I just need some clarity on how it worked when it was published in the 70s. Now I know that it works with public keys but did it also work with ...
2
votes
3answers
796 views

An unbreakable book cipher?

In a recent press interview, a former terrorist of the 1970s described the cipher his group used to communicate. He claimed that method was unbreakable and I wonder if cryptographers today would agree....
5
votes
1answer
237 views

How did “Secure Voice” work on the old Air Force One's?

I recently visited the "Museum of Flight" where they have an old SAM 970, previously known as "Air Force One". Inside there is a comm station with many buttons designated "Secure Voice", as can be ...
15
votes
1answer
706 views

Who issued the first SSL certificate?

When SSL was introduced in ~1996, there was only a few CAs issuing certificates for that specific use and a few sites which actually used SSL. Which Certification Authority issued the first SSL ...
5
votes
2answers
186 views

Steganography in speech by adding extra “filler” syllables [closed]

PREAMBLE About 20 years ago, when reading a novel (set in late 1800) by some classic Russian writer I came across very curious example of steganography. The two main characters were peasants who got ...
4
votes
2answers
636 views

Major code breaks in history

What are the major code breaks in the history of cryptography? Which code breaks changed the face of a battle or another major event? Which one had nationwide consequences?
3
votes
1answer
570 views

Have affine ciphers actually been used in practice?

I have been been studying some basic ciphers, and learnt about the affine cipher where the encryption function is given by $ax+b \pmod{26}$ for an alphabet with 26 characters. This is a very insecure ...
1
vote
1answer
70 views

How does Fialka manage to have a letter encipher unto itself?

http://www.cryptomuseum.com/crypto/fialka/index.htm Fialka was an electromechanical rotor machine. How does it manage to have a letter encipher unto itself. I realize it does something clever by ...
5
votes
1answer
246 views

Time gap between Diffie-Hellman Key Exchange and ElGamal encryption?

I'm looking into the Diffie-Hellman key exchange paper (New Directions in Cryptography, 1976) as part of a series of classic papers in Cryptography for my Ph.D and I was wondering if someone could ...
4
votes
1answer
108 views

Has the Linear Congruent Generator ever been used in any of the early crypto algorithms?

The Linear Congruent random number generator is the simplest kind of pseudo random number generator. I know that its now long broken. But I am curious -- has it ever been used in any of the early ...
25
votes
6answers
4k views

Did a certain cryptography method get abandoned due to security flaws in the past?

I am researching how quantum computers affect current encryption methods (RSA and more). However, I remember learning in a course that there used to be a particular encryption method which was ...
28
votes
1answer
4k views

Examples of modern, widely used ciphers that suddenly fell?

RC4 and GOST are two major ciphers (defined as being widely used to encrypt large amounts of data) that fell to cryptanalysis (relatively) suddenly. The first becoming totally broken and the second ...
15
votes
3answers
514 views

Turing's (still?) classified inference engine algorithm?

Does anyone know the algorithm used by Turing's Colossus inference engine, so highly classified that the Brits kept it secret for decades after WW II? Indeed, it may still be classified. Several ...