Practical Cryptography

4BLOCK CIPHER

TANVEER AHMED, MOHAMMAD ABUL KASHEM, AND SAIFUL AZAD

Contents

Keywords

4.1 Block Cipher Principles

4.2 The Feistel Block Structure

4.3 Block Cipher Modes

4.3.1 Electronic Codebook (ECB) Mode

4.3.2 Cipher Block Chaining (CBC)

4.3.3 Cipher Feedback (CFB) Mode

4.3.4 Output Feedback (OFB) Mode

4.3.5 Counter (CTR) Mode

References

Keywords

Block cipher

Cipher block chaining

Cipher feedback

Counter

Electronic code block

Feistel cipher

Output feedback

A stream cipher is one that encrypts/decrypts a data stream character by character, i.e., one character at a time. All the ciphers discussed in Chapter 3 are stream ciphers. On the other hand, a block cipher encrypts/decrypts a block of n characters and produces an output of similar length. ...