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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?
Jul
16
comment Physical analogue for MACs
+1. To make this more analogous to a real MAC, we could assume that an attacker could steal the case (and everything inside it) and substitute a similar-looking one of his one -- only someone with the "real" key would discover that it doesn't unlock the replacement case, just as only someone with the real secret key can tell that a substituted message with a substituted MAC isn't the original message.
Jul
15
comment Physical analogue for MACs
@Reid -- you have two pretty good ideas here; I wish you had posted them as two separate answers, so that the "better one" (whichever that may be) would float to the top. +1 anyway.
Jul
13
comment Physical analogue for MACs
@PaŭloEbermann: Yes, that's how most MACs work -- everyone who can check the MAC can also produce their own. When teaching people about MACs, we want the physical analogue to have the same flaws as the actual MAC.
Jul
2
awarded  Popular Question
Jun
26
revised Simple protocol for 1-out-of-2 oblivious transfer
clarified (I hope)
Jun
26
suggested suggested edit on Simple protocol for 1-out-of-2 oblivious transfer
Jun
18
answered Is it possible to cryptographically prove when was the last time a ciphertext was decrypted/encrypted?
Jun
6
comment How can I split a message in parts of similar size or smaller?
Yes, your scheme is a pretty clever way to reduce the size.
Jun
6
comment How can I split a message in parts of similar size or smaller?
+1 for a working 3-of-3 approach. I'm pretty sure tha 2-of-3 (or X-of-Y) threshold schemes require longer messages; one approach is the very similar ssss and SecretSplitter.
Jun
4
comment Encrypt-then-MAC paradigm
The answers to Should we MAC-then-encrypt or encrypt-then-MAC? discuss the security properties of Encypt-then-MAC and compare them to MAC-then-encrypt and MAC-and-encrypt.
Jun
3
comment Encrypt user email but be able to find user by email
+1 Looks good. For some applications, if the attacker already has an email address on his list, then he can already send spam to that address -- it doesn't hurt anyone if that attacker can confirm that you have the same address on your list (or not). So for those applications, non-keyed hash functions are adequate. See suppression list and Store hashed email and compare hash values.
May
25
comment How random are commercial TRNGS
By "radio", are you perhaps referring to hardware random number generators based on radioactive decay, such as hotbits ?
May
24
answered Requiring a “supervisor” key pair and a “user” key pair to decrypt multiple-recipient messages