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I'm looking for a historical overview for the change in cryptographic power, which I hereby define as

How far state-of-the-art cryptography is ahead of state-of-the-art cryptanalysis.

In other words, how secure was a message encrypted with the best available methods from the attackers of its day, up to and including today?

Was the Caesar cipher, when used by Caesar, more secure than the Vigenère cipher, when used by Napoleon? Was the Vigenère cipher in the 16th century easier or harder to break than AES is today? Could AES be broken today with less effort than it took to crack the Enigma code in WWII?

I realize this is a very broad question, and difficult to answer with certainty, but any concrete examples backed by references would be of great interest to me (such as, how commonly the Vigenère cipher was broken when it was in wide use).

(Please discount side-channel attacks such as "rubber-hose cryptanalysis".)

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closed as too broad by e-sushi, DrLecter, AFS, rath, Thomas Feb 23 at 23:28

There are either too many possible answers, or good answers would be too long for this format. Please add details to narrow the answer set or to isolate an issue that can be answered in a few paragraphs.If this question can be reworded to fit the rules in the help center, please edit the question.

    
Nowadays crypto is all about designing higher level protocols, avoiding implementation mistakes, usability etc. Primitives like AES are pretty strong. –  CodesInChaos Feb 23 at 13:58
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This is too broad. (Just when I thought it couldn't get broader than this…) You know, we expect you to do some research on your own first. What research have you done? Did you check anything else besides Wikipedia? Did you - at least - check Crypto.SE? Can you list all ciphers you found? Did you do a literature search? Basically, don't expect us to do all your work for you… –  e-sushi Feb 23 at 15:02
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Remove times earlier than the 1980s (or earlier if you include non-public state-of-the-art) and the question is no longer arguably too broad; and answer is: so far ahead that it became immaterial. The designers of DES knew what it takes to make a practically unbreakable block cipher (DES's key and even block size is only a compromise, with authorities and performance). I like the observation that side-channel attacks include rubber-hose cryptanalysis. –  fgrieu Feb 24 at 8:16
    
^^ what he said. Also I would comment that you shouldn't be wiping out all sidechannel attacks - most of them are very relevant indeed. This might be what you meant (I'm hoping you meant "Discount stupid side-channels that involve physical threats to a privileged user") but this could be clarified –  figlesquidge Feb 24 at 12:19
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