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Sep
29
comment Cryptographic data structure: sparse array without membership test
If the person writing data could keep track of exactly what key,value pairs he has written so far (in some in-RAM structure that the attacker, and hence the reader, won't have access to once the computer is shut down), then perhaps the surprising-to-me dirty paper coding approach could be used -- rather than "most recent value wins" every collision, sometimes "let the older value win this collision" is better when there is enough error correction that the new value can still be recovered from other, non-colliding bits.
Sep
29
comment Cryptographic data structure: sparse array without membership test
+1. And thank you for making "Is deniable error-correction possible?" a separate question.
Sep
29
comment Cryptographic data structure: sparse array without membership test
@gmr: yes, very similar to your solution, except this proposal doesn't require decrypting the 'k' value and checking if the decrypted 'k' value matches the current 'k' value. So this proposal apparently runs a little faster.
Sep
28
answered Cryptographic data structure: sparse array without membership test
Sep
27
answered Is deniable error-correction possible?
Sep
27
comment Cryptographic data structure: sparse array without membership test
This sounds distantly related to multiple-message encoding in steganography. Alice carefully constructs an image that appears to be an innocent cat photo, but embeds multiple messages inside such that Oscar can extract one message from Alice, Trent can extract another message from Alice, but Oscar and Trent (assuming they don't collaborate) can't even detect that any other message exists in the image. Can one of the multiple-message encoding techniques be adapted to solve this problem?
Sep
24
comment Understanding Pseudo Random Generators
@TravisMayberry: Would you mind telling me what "n" is for RC4/CipherSaber, Salsa20, or some other real PRNG implementation? Or are you pointing out a difference between the theoretical definition, and what I see in practice?
Sep
23
answered Understanding Pseudo Random Generators
Sep
23
answered Key management for military GPS receivers
Sep
21
comment Single-purpose symmetric encryption scheme for single files
For the "file" command to work properly, you're going to want the first few bytes of the file to describe what kind of file this is -- often the the name of the program that produces the file (in UTF8 characters), followed by a version number.
Sep
21
comment Single-purpose symmetric encryption scheme for single files
What is the advantage over " 7z a -p outfile infile.txt "? (Perhaps using 'tar', as described in the 7z man page, to store the metadata). See "7-Zip's AES encryption".
Sep
16
answered The difference between being not strongly collision resistant, and not weakly collision resistant?
Sep
12
answered Are there cryptographic hash functions with homomorphic properties?
Sep
2
revised Repeatable crypto
clarify (I hope)
Sep
2
comment Repeatable crypto
Yes, a system that lets the attacker get the encryption key -- is broken. However, there is a way to attack the deduplication, even if the attacker doesn't know the original key.
Sep
2
revised Repeatable crypto
say a few words about chosen-plaintext attack
Sep
1
answered Repeatable crypto
Aug
31
revised Repeatable crypto
add "host-proof" tag
Aug
29
comment What is the most secure hand cipher?
@AaronToponce: by "this", do you mean the cipher is impractical, or that the cipher is practically secure against this attack because this particular attack is impractical?
Aug
28
answered Security of very simple XOR with random?