Reputation
2,110
Top tag
Next privilege 2,500 Rep.
Create tag synonyms
Badges
5 11
Impact
~46k people reached

Feb
6
revised How to break Universal Re-Encryption algorithm?
deleted 1 character in body
Feb
6
answered How to break Universal Re-Encryption algorithm?
Feb
6
comment How to break Universal Re-Encryption algorithm?
Possibly relevant crypto.stackexchange.com/a/18954/553
Jan
9
revised What are the main weaknesses of a Playfair cipher, if any?
slight expansion
Dec
23
comment SHA256 message bytes
Indeed. It's a key expansion in a way: the message is the key for the cipher (at the core of SHA26) and is expanded from 16 32-bit words to 64 32-bit words. The state is then handled as the message (with a xor feed forward for non-reversibility)
Dec
22
answered AES Inverse Key Schedule
Dec
17
comment Factorizing N to derive D
long is also not big enough. Use gmp or some other bignum library, if you want C. Of course Python will do this OK, as it has bignums built in.
Dec
14
awarded  Necromancer
Dec
12
comment Message exchange with textbook RSA
I agree, but it's just a conceptual exercise, I suppose. It might be part of some algebra course without crypto focus, e.g., so padding, replay attacks etc. are not relevant, but just the application of some algebra theory that was just treated, e.g. I didn;t want to get things in that the OP wouldn't know about.
Dec
12
answered Message exchange with textbook RSA
Dec
12
answered Attack on textbook RSA with small messages
Dec
11
comment Why does GPG ciphertext length differ with fixed plaintext length?
The base64 difference is expected. If we input $n$ bytes, we have $4(n/3 + 1)$ output bytes if $n$ is not evenly divided by 3, and $4(n/3)$ otherwise. So a difference of 4 between 389 (remainder 2) and 387 (no remainder) is clear, and cannot be helped. That is how base64 encoding works.
Dec
11
comment Why does GPG ciphertext length differ with fixed plaintext length?
Can you give the complete gpg command ? Giving the string on the command line interprets it as a filename, so you must do something else. All details can matter.
Dec
11
comment Why does GPG ciphertext length differ with fixed plaintext length?
Just a remark: base64 is not encryption, just a standard way to transfer/display binary data as text data.
Dec
8
answered Different tools return different ciphertext value for equal input
Dec
8
comment Different tools return different ciphertext value for equal input
Let us continue this discussion in chat.
Dec
8
comment Different tools return different ciphertext value for equal input
Can you load your own key into the HSM? Then it would be testable
Dec
8
comment Different tools return different ciphertext value for equal input
The online tool seems to use ASCII values as the key (so it's crap, basically), if the test vectors below on the page are to be believed. So your hex input is interpreted as ASCII, not as bytes encoded as hex-ASCII.
Dec
8
comment Different tools return different ciphertext value for equal input
You cannot without the actual key bytes that are used, essentially.
Dec
8
comment Different tools return different ciphertext value for equal input
It seems strange that an HSM could leak its key, which is unusual. Moreover, your keyvalue is, after the first two bytes 86 01 the ASCII "nerated DES3 Key", followed by null bytes. So I don't think it's the actual key, but something else. The first two bytes "ought' to be 47 65 for "Ge", to make even more sense