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An Overview of Cryptography
- bordapapa 7y agoThis is such an awesome paper, thanks for posting it!
- devhwrng 7y agoGreat paper! Given the write-ups of old and broken crypto, perhaps a better title would be History of Cryptography?
- FabHK 7y agoIndeed. Interesting mix of theory ("here's how RSA works and why") and practice (list of specs and RFCs), but very old-school. Today, I'd expect less focus on RSA and PGP, and instead a mention of elliptic curves, the Signal protocol (double ratchet), etc.
- ljhsiung 7y agoIt does say at the top "originally written in 1998" and it was basically amended over time, but regardless I still love learning about "historical" views. Example: A textbook from '95 had a pretty large section on "the future" of ECC and "current" trends in research. It was interesting seeing what came true, or what was still being worked on.
- smbl64 7y agoVery interesting paper indeed. Could be more appealing if the vanilla html was properly styled though.
- ShorsHammer 7y agoI find it fairly decent, far better than the usual academic pdf anyway if that's the standard most accept. How would you improve the page?
- beefhash 7y agoMy personal tweaks: body { font-size: 19px; width: 72ch; font-family: Charter; margin: 0 auto; line-height: 1.4; } and then remove the size= option on the <font> element.
- galadran 7y ago"This scheme also provides nonrepudiation since it proves that Alice sent the message; if the hash value recovered by Bob using Alice's public key proves that the message has not been altered, then only Alice could have created the digital signature." This is a common misconception. Just because a signature verifies under Alice's public key, it does not necessarily imply Alice generated the signature. For many common signature schemes, if Bob makes a signature using their public/private key, Alice can produce a different private/public key such that Bob's signature will verify under Alice's key. Paper (we) wrote on the impacts of this: https://eprint.iacr.org/2019/779 https://eprint.iacr.org/2019/779
- throwawaymath 7y agoIn particular, see also this 2005 paper by Thomas Pornin: http://www.bolet.org/~pornin/2005-acns-pornin+stern.pdf http://www.bolet.org/~pornin/2005-acns-pornin+stern.pdf EDIT: Looks like this paper is also already included in the list of citations for the 2019 paper :)
- arkadiyt 7y agoLetsEncrypt was vulnerable to this exact attack - it let people issue valid TLS certificates for domains they didn't control: https://www.agwa.name/blog/post/duplicate_signature_key_selection_attack_in_lets_encrypt https://www.agwa.name/blog/post/duplicate_signature_key_sele...
- 7y ago
- namdnay 7y agoI strongly recommend “The Code Book” by Simon Singh. Really readable and very informative!
- kyteland 7y agoIt's a great read if you're not too in depth on the topic and want an overview, but it is badly in need of a modern revision that removes some of the more speculative parts of the last chapter and replaces it with what actually happened in the last 20 years.
- marknadal 7y agoFor those who want a conceptual, visual, cartoon explainer, check out our 1min animated series: https://gun.eco/docs/Cartoon-Cryptography https://gun.eco/docs/Cartoon-Cryptography
- AllanHoustonSt 7y agoCryptography was both my favorite topic in school and the one that cemented my realization in that I wasn't good enough to do math for a living.
- baby 7y agoShameless plug: I’ve been writing my own introduction for students/developers/consultants/... and you can read it online for free it seems (or at least some chapters): https://www.manning.com/books/real-world-cryptography https://www.manning.com/books/real-world-cryptography
- ShorsHammer 7y agoThe Bleeding Edge section has much on the current status of post-quantum attempts?
- conston 7y agoThis is an awesome resource. I am definitely going to bookmark this for future reference. I would also recommend reading Applied Cryptography by Bruce Scheneier. You can pick it up in hard copy or kindle on amazon. This book is considered the most definitive reference on cryptographic techniques ever produced.
- ianstormtaylor 7y ago"In many of the descriptions below, two communicating parties will be referred to as Alice and Bob; this is the common nomenclature in the crypto field and literature to make it easier to identify the communicating parties. If there is a third and fourth party to the communication, they will be referred to as Carol and Dave, respectively. A malicious party is referred to as Mallory, an eavesdropper as Eve, and a trusted third party as Trent." I really love this naming system.
- SilasX 7y agoI may be misunderstanding the author's use of terms here, but this seems wrong (section 3.1): > A block cipher is so-called because the scheme encrypts one block of data at a time using the same key on each block. In general, the same plaintext block will always encrypt to the same ciphertext when using the same key in a block cipher whereas the same plaintext will encrypt to different ciphertext in a stream cipher. A block cipher will turn the same plaintext into the same ciphertext only if you're using it with the ECB mode; otherwise, the same plaintext in different places with the same key will encrypt into different ciphertext. If he means "key" in the sense of "final thing that gets XORed to make the ciphertext", then that's true, but then it's equally true of stream ciphers as well.
- GordonS 7y agoI took this to mean "in the simple case" (which would be ECB), but the wording could be improved here to make that clearer.
- SilasX 7y agoRight, especially since a few paragraphs down, he introduces all the different modes, including ECB.
- GordonS 7y agoTo me at least, it makes sense to introduce a complex topic gradually, in stages. But regardless, I still agree that the wording in the paragraph you called out could be improved for better clarity.
- SilasX 7y agoSorry to keep hammering on this, but ... I don't know in what context it would be reasonable even as a simplification to say that block ciphers are semantically insecure like that. Anyone who listed that as a disadvantage to block ciphers should be regarded as confused, not speaking from a big picture perspective. Furthermore, even if you're going to explain it that way as a result of building up the complexity gradually, you need to explicitly "unring" that bell, e.g. "Earlier I said X, but actually Y...". This author didn't.
- Beldin 7y agoSide note: Diffie-Hellman predates RSA. I attended a talk by Rivest once, where he vividly described how that paper triggered them into exploring whether public key crypto was really possible or not. They ended up constructing RSA from those sessions.
- flowersjeff 7y agoHoly smokes - I 'ran' into this website a few weeks ago whilst cleaning up an old computer.... and chuckled (my copy that I had saved on this computer is/was old - lets just say that). And then I chance upon it being talked about on HN. Small world and maybe the universe is telling me something ;-)