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Information Security
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re: DES Key Exchange
Ryan Pierce / Townsend Analytics Ltd. / Archipelago LLC
28 Feb 2001 6:33PM ET> When using encryption method 2 with logon messages a master key is agreed upon by both parties in advance. How would one know the IVEC used for the same logon message? Would the parties need to set an IVEC in advance as well?
You are talking about using DES in ECB (Electronic Code Book) mode. ECB mode uses no initialization vector. The encryption function depends solely upon the 8-byte plaintext block, and the 56-bit key.
DES in CBC (Cipher Block Chaining) mode (i.e. PGP-DES-MD5) requires an Initialization Vector. Encryption in CBC mode depends upon the 8-byte plaintext block, the 56-bit key, and the previous 8 bytes of ciphertext (or, if the first encryption of the day, the Initialization Vector.)
re: DES Key Exchange
Ryan Pierce / Townsend Analytics Ltd. / Archipelago LLC 28 Feb 2001 6:33PM ET
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