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09.09.2008 at 07:41PM PDT, ID: 23717906
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Attachment Details

Where to store the Salt?

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7.4
Zones:

Encryption for Network Security, .NET

Tags:

Encryption, Rijndael, AES, Salt
I cant quite get a grasp on salts specifically pertaining to Symmetric Key Algorithms such as Rijndael. I'm doing some encryption in .Net using the managed Rijndael algorithm and I derive the key using Rfc2898DeriveBytes. It takes a plain text password and bytes of salt and performs multiple iterations of hashing to produce the byte key.

So, I generate some random bytes and compute the key, but now to decode I'm going to need those same salt bytes along with the same password of course. So how do I remember all these salts? Can I append them to the encrypted bytes then pull them back for decrypting? They definitely arnt private that way.

If they arnt private, than what is the point? The only thing I really see going on is that the same file encrypted with the same password but different salt will yield difference bytes but how does it help against brute forcing of the password if the salt is know? [brute attemp]+(knownsalt)

If they are to be private, then why wouldn't the suggestion just to be to generate an entire random key for each file?


Thanks for the help, now excuse me while I go pour some salt in my eye.
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Answered By: arnold
Expert Since: 04/18/1997
Accepted Solutions: 1118
arnold has been an Expert for 11 years 8 months, during which he has posted 4638 comments and answered 1118 questions. arnold is just one of 803 experts in the Encryption for Network Security Zone. 4 experts collaborated on this answer, which was graded a "B" by the asker.
 
 
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