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Regarding DES/3DES




I send you a text from The ESP Triple DES Transform draft
"draft-ietf-ipsec-ciph-des3-00.txt"
	4.2. Manual Key Management
	When configured manually, three independently generated keys are
required, in the order used for encryption, and 64-bits (8 	bytes) are
configured for each individual key. Keys with incorrect parity SHOULD be
rejected by the configuration utility, 	ensuring that the keys have been
correctly configured. Each key is examined sequentially, in the order used
for encryption. A 	key that is identical to a previous key MAY be
rejected. The 64 known weak DES keys [RFC-1829x] SHOULD be rejected.

If you K1 and K2 are identical it's just like DES with K3.

http://www.ietf.org/internet-drafts/draft-ietf-ipsec-ciph-des3-00.txt

I hope micr*s*ft do this check in is super "encryption pack".

p.s. Check the weak keys into Schneier p. 233 (Schneier, B., "Applied
Cryptography", John Wiley & Sons, New York, NY, 1994. ISBN 0-471-59756-2 ).
Or from FIPS74 ( US National Bureau of Standards, "Guidelines for
Implementing and Using the Data Encryption Standard", Federal Information
Processing Standard (FIPS) Publication 74, April 1981,
http://www.itl.nist.gov/div897/pubs/fip74.htm ).

>Hello

>I have  query regarding using DES and 3DES for encryption.
>RFC 2420 states that - for 3DES
>"The keyed DES function is iterated three times, an encryption (E) followed

>by a decryption (D) followed by an encryption (E), and generates the 
>ciphertext (C1) for the block. Each iteration uses an independent key: k1, 
>k2 and k3. To decrypt, the order of the functions is reversed: decrypt with

>k3, encrypt with k2, decrypt with k1, and XOR with the previous cipher- 
>text block."

>Since 3 different keys are used in 3DES, is it that the second and third 
>keys (k2 and k3) are generated using the first key(k1) ?

>If not, then how are the second and third keys (k2 and k3) generated  ?

>Regards
>Ruheena Rashid.



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