Moreover password hashing algorithms like PBKDF compose their hash function multiple times (it is recommended to iterate PBKDF-2 a minimum of 1000 times, each iteration applying SHA-1 twice) making this attack doubly impractical. A salted hash would completely eliminate any ability to look up accounts by email address, since you would have to hasnt the email against the salt for. Specifies the salt value when generating remember tokens. That said, RememBear will only encrypt and decrypt the items on your physical device. Specifies the password hash algorithm to use when hashing passwords. It stores your items, including passwords, in an encrypted file on your device and on our secure servers for sync and backup purposes. But a cryptographically secure hash function is deliberately designed to have multiple rounds, each of which uses all the bits of the input string, so that computing the internal state just prior to the addition of the salt is not meaningful after the first round. RememBear encrypts your items using both your Master Password and a unique device key generated by the application. With prefixed salt there would be nothing in common between the calculations for each dictionary word.įor a simple hash function that scans linearly through the input string, such as a simple linear congruential generator, this is a practical attack. It could then be cheaper to brute-force a password file entry with postfix salt than prefix salt: for each dictionary word in turn you would load the state, add the salt bytes into the hash, and then finalise it. You should be worried about hash to password lookup tables, rainbow or attacker has 'rainbow tables' consisting not of the hashes of dictionary words, but of the state of the hash computation just before finalising the hash calculation. By trading computation for space, a lookup table that would take 1000 TB can be compressed a thousand times so that it can be stored on a smaller drive drive. A "rainbow" table is just a particular kind of lookup table, one that allows a particular kind of data compression on the keys. First of all, the term "rainbow table" is consistently misused.
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