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visits member for 3 years, 3 months
seen Nov 13 at 16:01

Dec
3
awarded  Notable Question
Nov
25
revised Is the following symmetric design secure?
fix oops -- need a random permutation here, not a random function.
Nov
23
revised Is the following symmetric design secure?
rough draft of a proof
Nov
23
answered Is the following symmetric design secure?
Nov
19
awarded  Nice Question
Nov
13
awarded  Excavator
Nov
13
revised Attack XOR encryption of binary data compressed by zlib with known key length (very short key)
Is this what you really meant?
Nov
13
revised Determine the Key given ciphertexts and plaintexts?
forgot to update B0 and B1
Nov
13
answered Determine the Key given ciphertexts and plaintexts?
Nov
13
comment How can we get CA's public key?
@CodesInChaos: make that an answer.
Nov
12
asked Is there a cryptographic hash function that can be performed with pencil and paper?
Nov
12
comment How would I make a secret notation alphabet more secure?
You might enjoy looking at shorthand systems such as Gregg shorthand -- they were never intended to be difficult to decode, but some stenographers use so many of their own custom abbreviations that even other stenographers using the same system have difficulty reading it.
Nov
12
comment Is this hand cipher any more secure than the Vigenère cipher?
You could get a lot better diffusion if, rather than handle each letter independently with "mod 26", you allow a carry over -- i.e., when adding 5 to X and obtaining C, you get a "carry over" that changes the next column from E+3=H to E+3+1=I.
Oct
23
comment What is the most secure hand cipher?
@makerofthings7: if it is used properly, as Smit Johnth pointed out, then OTP is completely immune to statistical analysis and every other kind of ciphertext-only analysis, no matter how the letters are encoded into numbers -- ASCII, Baudot code, Morse code, etc. See Wikibooks: one time pads for more details.
Oct
16
comment Any efficient text-based steganographic schemes?
This steganographic scheme is called an acrostic ( Wikipedia: acrostic ).
Aug
26
awarded  Yearling
Aug
25
revised Convert old and busted password encryption to something sensible
mention another competing format
Aug
13
answered Is it possible to subtract/multiply numbers using homomorphic encryption?
Aug
4
answered Convert old and busted password encryption to something sensible
Aug
4
comment Why are there $ signs in my passwd file?
+1. Recently people at Wikipedia shuffled things around. Is crypt (C) on Wikipedia what this answer ought to link to?