1,539 reputation
1416
bio website
location Madrid, Spain
age
visits member for 1 year, 11 months
seen 10 hours ago

Oct
31
comment How to use HMAC-SHA1, HMAC-SHA2 in conjunction with AES
@user907810 - I can't speculate as to what's happening internally in your library. Regarding a 'master key', well assuming you begin with a 128-bit (minimum) cryptographically strong key (the master key), you could use something like HKDF to derive encryption and authentication keys.
Oct
31
answered How to use HMAC-SHA1, HMAC-SHA2 in conjunction with AES
Oct
27
comment The weak link is the password?
@MarkLitovsky - directly from wikipedia: "When the standard was written in 2000, the recommended minimum number of iterations was 1000, but the parameter is intended to be increased over time as CPU speeds increase." I've heard it said that the number of iterations should (roughly) be doubled every year. 100000 or a million iterations these days is common. Of course, nowadays, things like scrypt offer better protection.
Oct
26
comment The weak link is the password?
@MarkLitovsky - PBKDF2 is used in Truecrypt. The user-selected hash algorithms you refer to are used as the underlying hash in PBKDF2, and also in Truecrypt's PRNG. It's worth mentioning, however, that Truecrypt only uses 1000 PBKDF2 iterations, which is far too few.
Oct
25
comment Do any non-US ciphers exist?
Salsa20's author is DJB - an American. Don't hold that against him though - he's a freedom fighter.
Oct
25
comment Do any non-US ciphers exist?
"USA represent large amount of the entire worlds population" - it represents less than 5%, actually.
Oct
25
revised Hypothetical unknown cipher - security in obscurity?
substituted the word 'alien' for 'attacker'
Oct
25
comment Which crypto libraries/programs do we have the most confidence in?
This question is likely to be closed because it's primarily opinion based, and too subjective to answer. However, I'm interested to hear the answers nonetheless.
Oct
25
comment Hypothetical unknown cipher - security in obscurity?
Your question reads like a Choose Your Own Adventure book. They're valid questions - but I suggest you break them up into smaller, more answerable questions. I also suggest you read on up Kerckhoffs's principle.
Oct
25
suggested suggested edit on Hypothetical unknown cipher - security in obscurity?
Oct
24
comment Knowing pre-encryption data, can we find the private key CryptoLocker used?
Read up on known plaintext attacks. If the files have been encrypted with a modern symmetric cipher (likely) such as AES, you're out of luck.
Oct
23
answered Would it be possible to generate the original data from a SHA-512 checksum?
Oct
22
comment Implementing OpenSSL padding
@user4982 - PCKS5 padding is recognizable in the ciphertext by comparing its length with that of the cleartext.
Oct
22
comment Implementing OpenSSL padding
I'm no openssl expert here, but the documentation states: "All the block ciphers normally use PKCS#5 padding also known as standard block padding". I tried your code from the command line and padding was indeed used. Keep in mind that padding might just be a single byte, depending on the length of the input.
Oct
20
comment Serpent block cipher : S0 to S7 functions unclear
@archie - fair point - although Cryptix is now defunct, and besides, the Cryptix dev team is already credited in the JSerpent source (along with the original authors of the algorithm).
Oct
18
comment Serpent block cipher : S0 to S7 functions unclear
Have you had a look at this bitslice implementation in java?
Oct
18
comment Order of cascaded ciphers
@fgrieu - would you mind clarifying "truly independent keys" as opposed to ciphers that "share their key"? How would you classify two "statistically independent" keys derived from a KDF with the same input?
Oct
15
comment Decrypting encrypted files if i have the original files(Plain Text attack)
Off-topic because: Requests for analyzing or decyphering a block of data are off-topic here, as the results are rarely useful to anyone else.
Oct
14
answered Is scrypt a hashing function, encryption, or PBKDF?
Oct
13
comment How does GCM (Galois/Counter Mode) work?
While I appreciate the effort - copying and pasting large portions of an RFC is not really appropriate as an answer - and is not helpful to the community. But then again, neither is asking a question which could be answered by simply reading the RFC.