3 ms·
The main problem with this question is I get a lot a answer that simply aren't answer to this question, but only the basic good usage of cryptography. Until he
by yogsototh 15y ago
The main problem with this question is I get a lot a answer that simply aren't answer to this question, but only the basic good usage of cryptography.
Until here, nobody said 'yes', then I assume my method is secure.
I would have loved to know if this specific question is asked for any kind of hash function, or if nobody never ask such question. For me it seems as a natural question which seem a bit more difficult than finding a collision but easier than cracking completely the hash function.
- dchest 15y agoTo answer your question, AFAIK there are no known first preimage attacks on SHA-1 yet. And no, your method is not secure.
- yogsototh 15y agoThanks for your answer. Could you explain me how my method is not secure assuming: 1. The pass is long 2. The preimage is known If nobody can find `sha1(knownpart|hiddenpart)`, how is my method insecure? Is the problem linked to sha1 or if I use any other hash this method also fail? I presume the _only_ method you advocate for is to have a lot of different passwords for each website is to store randomly generated password inside a keychain system. Could you enlighten me? How do you deal with your own password? Thanks. edit: it seems we reached the max depth. Thank you Dmitry!
- dchest 15y agoTable on estimated cost of hardware to crack a password in 1 year from scrypt paper: http://i.imgur.com/sAOwS.png http://i.imgur.com/sAOwS.png I personally use a scheme similar to yours, but with PBKDF2. Also, I'm no crypto expert.