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The salt isn't key, it wasn't a secret. In the original UNIX password encryption a 12 bit number derived from rand() calls was used to transpose the first 12 and the third 12 entries in a copy of the DES algorithm's E Permutation table. The salt was store in the password field of the password file, the trailing two characters, each one of a set of 64 ...


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No, they are not conceptually related. A keystream is the output of a stream cipher and is of (effectively, for modern ciphers) infinite length. If you need to encrypt more plaintext, you use the cipher to produce more bytes of keystream. On the other hand, password salts are of fixed size and their purpose is to make every password effectively unique. A ...


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To sum up and expand on the previous answers and comments, if everything goes to plan salts may only need to be distinct, but in practice there are attacks that can be avoided by always generating a new salt whenever the password is changed. If an attacker gets access to multiple different password hashes with the same salt (due to multiple compromises or ...


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If the existing salt is random (and chosen from a large enough space), there is little or no benefit to changing the salt each time the user changes their password. There's no downside -- you might as well change the salt each time the user changes their password; that is probably good practice -- but if you don't change the salt, it's unlikely that ...


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If the attacker had already begun creating a rainbow table or is engaged in some other attack which requires knowledge of the salt, then a password change with a salt change will require the attacker to start from scratch. Always assume the attacker has before and after copies of the password hash and salt. If the salt is not changed, any work the attacker ...



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