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comment What is the history of recommended RSA key sizes?
@Lembik Moore's Law indirectly affected RSA key sizes from two angles: Cryptanalysis and commercial hardware. Whilst refined algorithms could influence cryptanalytic efficiency, swapping out one key size for another would still be influenced by the latency of the available hardware. The "spread" of recommendations from 512 - 2048 back then, or from 1024 - 4096 today depend on the business tradeoffs for a given system. It cost RSA nothing to recommend 2048 bits for third-parties. They could have just as easily recommended 32768 bits if any one would take them seriously.
Oct
18
revised What is the history of recommended RSA key sizes?
changed timeframe to reflect RSA press release date
Oct
18
comment What is the history of recommended RSA key sizes?
Oop. I was too busy scanning for a non-existent byline to read the press release section. Updated probable cutover.
Oct
18
comment What is the history of recommended RSA key sizes?
@fgrieu Yes, I can well imagine that existing infrastructure could be using very low key sizes; perhaps due to design constraints. I hope they are also relying on hardware resilience of some sort, as 321 bits is well within the capability of modern GPU arrays.
Oct
18
awarded  Critic
Oct
17
answered What is the history of recommended RSA key sizes?
Oct
17
comment What is the history of recommended RSA key sizes?
@fgrieu So we have a 1974 lower bound. I wonder at what point the recommendations, such as derived in Table 1 of the paper, became explicitly linked to Moore's law, which interestingly enough was published a decade earlier. As once they became explicitly linked in any formal cryptogaphic literature, you could then just look at regular whitepapers and articles on Moore's Law for the answer.
Oct
15
comment Is there any existing cipher capable of scaling from a 1 bit key up to a one-time-pad?
@fgrieu However, I'd like to step back a bit and ask: If we stay true to information-theoretic security, where we only have as much security against known plaintext attacks as the entropy we bring with us, what type of universal scaling encryption algorithm can exist? So the usual real world security criteria jump the gun in this regards, as we already have chained block ciphers that step-side entropy. Naturally the XOR boolean primitive isn't a scaling cipher as the key material is only applied to a subset of the plaintext.
Oct
15
comment Is there any existing cipher capable of scaling from a 1 bit key up to a one-time-pad?
@fgrieu Once the implications of Shannon's work were absorbed in the 1950s, cryptographers strove for ciphers that wouldn't be breached once N bits of plaintext were known for an N bit key.
Oct
15
revised Is there any existing cipher capable of scaling from a 1 bit key up to a one-time-pad?
simplifying the question
Oct
15
comment Is there any existing cipher capable of scaling from a 1 bit key up to a one-time-pad?
@fgrieu I'll drop the side note about key lengths above 1:1 as that's a logistical scenario rather than an algorithmic quality.
Oct
15
comment Is there any existing cipher capable of scaling from a 1 bit key up to a one-time-pad?
@fgrieu I don't want to narrow the paradigm excessively; but I think the key criteria for genuinely scalable encryption is that an algorithm is honest in regards to information-theoretic security. If there is 1 bit of entropy then there are two (2^1) possible messages, if 2 bits then are 4 (2^2) possible messages, and so on.
Oct
15
asked Is there any existing cipher capable of scaling from a 1 bit key up to a one-time-pad?
Oct
14
comment Can Diffie-Hellman be scaled up or force-multiplied?
From what I recollect, quantum computing doesn't solve certain classes of encryption any better than normal computing.
Sep
2
awarded  Yearling
Oct
18
comment Are there any hand ciphers not obsoleted by computer cryptanalysis?
@WilliamHird A scenario would be a journalist investigating abuses in a totalitarian state. Journalist generates a series of one-time pads (literal pads) and keeps a photocopy/scan of them in a secure bank vault in their democratic home country. While taking interview notes and other observations in the totalitarian state, each note is encrypted with a one-time pad which is then burned. Once the journalist gets home, they can decrypt their notes. You'd probably also want physical hiding techniques for the pads and the encrypted notes.
Oct
18
comment Is there any strong enough pen-and-paper or mind cipher?
+1. As the question didn't mandate you had to remember the key in your head; and 'cipher' terminology excluding one-time-pads is splitting hairs for this question.
Oct
13
revised How exactly is “true randomness” defined in the realms of cryptography?
short version of answer
Oct
13
comment How exactly is “true randomness” defined in the realms of cryptography?
If this @Tanath I assume you are going to comment on the down-vote.
Oct
13
answered How exactly is “true randomness” defined in the realms of cryptography?