How is DES used with CBC?

Green Ideology

1/19/24, 8:07 PM

I'm reading our school's notes for cryptography, and it does a good job explaining CBC and DES in detail, but it fails to provide good information on how they are related.

From what I've researched so far, it appears that CBC is essentially a series of block ciphers, and DES can be used for the block cipher encryption process.

Is that it, or are there some other ways these are related? I'm really lost here/new to cryptography, and any help would be really appreciated. Thanks a lot!

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des

block-cipher

cbc

forest

1/19/24, 9:21 PM

This is an awfully basic question. Did you try looking elsewhere on the site to find an explanation of block ciphers and modes of operation?

Score:1

Crypto

kodlu

1/19/24, 8:45 PM

CBC is a mode of operation, and is defined for an arbitrary block cipher, which can be DES, AES or whatever you like. See Wikipedia for example.

A block cipher typically processes 64 bit or 128 bit blocks using a pseudorandom permutation. Typically, the messages we want to encrypt are much longer, and modes of operation achieve this while satisfying some security properties. The ingredients used are typically a public random initialization vector, and a means of connecting the encryption of the next block to some variable resulting from the previous block, which enhances the security properties of the encryption for the overall message.

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