Notes for January 15, 1997
Would it help to put out code for using getpwnam and getgrent?
Gene will discuss this program in section, too
Puzzle of the day
Breaking UNIX crypt(1)
No right answer, but there are better places to look than others.
I'll ask this one periodically to see how your knowledge is changing.
Purely statistical attack is possible (me)
but it takes gobs of ciphertex
Known plaintext attack: that's Reeds and Weinberger's attack,
with a nice suggestion by Bob Morris
Basic idea: 2 keys, one private, one public
Cryptosystem must satisfy: (a), given public key, CI to get private key;
(b) cipher withstands chosen plaintext attack;
(c) encryption, decryption computationally feasible
[note: commutativity NOT required]
Benefits: can give confidentiality or authentiction or both
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Page last modified on 1/23/97