4 ms·
I can't see how this help with the brute force attack: you start with a password and compute hash. The suggested scheme doesn't make it more difficult (i.e. cpu
by lsh123 12y ago
I can't see how this help with the brute force attack: you start with a password and compute hash. The suggested scheme doesn't make it more difficult (i.e. cpu expensive) to compute the resulting hash from a given password than simply repeating the same MD5 or SHAXXX the given number of times. Moreover, the parameters for the hash functions (e.g. bit shift) are not random. They have been chosen on purpose. Using the input (password) to set these parameters will most likely result in some very weak hashes for specific passwords (including hash collisions).
- taejo 12y agoThe idea (I think) is that it's more difficult to build dedicated hardware for the brute force attack that's cheaper than doing it with a general-purpose CPU.
- beejiu 12y agoBut, it only makes it unbreakable for 50% of passwords? Would it not be better to have an alternating scheme, i.e. MD5 -> SHA1 -> MD5 -> SHA1 repeated 100,000 times, rather than choosing a scheme deterministically at the start.