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0 pointsthaumasiotes4y ago0 comments

Password salting has nothing to do with password reuse.

Imagine two people have accounts on each of two websites:

             eBay           YouTube
   
   Alice     sunlight       bobrules
   
   Bob       bobrules       bobrules

A password reuse attack dumps the YouTube database, cracks Bob's password, and then accesses Bob's eBay account. The fix for this is that Bob should use different passwords on his different accounts. Hashing helps by making step 2 ("crack Bob's password") more difficult. Salting does not affect this attack in any way. Note that the attacker didn't bother to dump the eBay database.

The attack that salting protects against dumps the YouTube database, cracks Bob's password, and then accesses Alice's YouTube account.

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growt4y ago

"Salting does not affect this attack in any way." Yes it does. If you habe unsalted passwords you can just use a rainbow table to look passwords up.

thaumasiotesOP4y ago

And that is not affected by salting. You can use a rainbow table to look passwords up whether or not those passwords are salted. There is zero conceptual connection between the two ideas.

Now, realistically, you can't use a rainbow table on passwords of any noticeable length, and a salt may push the password over the edge of that threshold. If that's really what you want... enforce a minimum password length.

growt4y ago

"Use of a key derivation that employs a salt makes this attack infeasible." https://en.wikipedia.org/wiki/Rainbow_table

"Salts defend against attacks that use precomputed tables (e.g. rainbow tables)" https://en.wikipedia.org/wiki/Salt_(cryptography)

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growt4y ago

"Salting does not affect this attack in any way." Yes it does. If you habe unsalted passwords you can just use a rainbow table to look passwords up.

thaumasiotesOP4y ago

And that is not affected by salting. You can use a rainbow table to look passwords up whether or not those passwords are salted. There is zero conceptual connection between the two ideas.

growt4y ago

"Use of a key derivation that employs a salt makes this attack infeasible." https://en.wikipedia.org/wiki/Rainbow_table

"Salts defend against attacks that use precomputed tables (e.g. rainbow tables)" https://en.wikipedia.org/wiki/Salt_(cryptography)

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