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Terms in this set (144)

Electronic Code Book (ECB) - breaks the plaintext down into 64 bit blocks and then encrypts each block separately BUT identical plaintext blocks are encrypted into identical ciphertext blocks

Cipher Block Chaining (CBC) - Each block of plaintext is XORed with the previous ciphertext block before being encrypted. This way, each ciphertext block depends on all plaintext blocks processed up to that point. To make each message unique, an initialization vector must be used in the first block. Fixes the issue of pattern recognition found in ECB. Errors can ripple through encryption of other blocks

Propagating Cipher Block Chaining (PCBC) - Each block of plaintext is XORed with the XOR of the previous plaintext block and the previous ciphertext block before being encrypted. As with CBC mode, an initialization vector is used in the first block.

Cipher Feedback (CFB): Allows encryption of partial blocks rather than requiring full blocks for encryption. This eliminates the need to pad a block like in CBC.
Cipher block chaining without full blocks. no need for padding. Combines block and stream cipher together. IV plus algorithm used to create a key stream to encyrpt the data.

The Output Feedback (OFB) mode makes a block cipher into a synchronous stream cipher. It generates keystream blocks, which are then XORed with the plaintext blocks to get the ciphertext. Block cipher working as a stream cipher

Like OFB, Counter mode turns a block cipher into a stream cipher. It generates the next keystream block by encrypting successive values of a "counter"