📝Block cipher mode of operation

tags: § Cryptography

Block ciphers can be used securely to encrypt a single fixed-size block of data.
A mode of operation describes how to apply a block cipher to transform data large than one block.

Initialization Vector (IV) is an important aspect of many modes of operation.
Because block ciphers work on fixed-size blocks, many modes of operation require padding.

Modes
- Electronic Codebook (ECB): the simplest mode of operation. Many security drawbacks. Not recommended.
- Cipher Block Chaining (CBC): a better mode of operation. Fixes data patterns hiding and randomizes encryption process so that encrypting the same input twice produces different ciphertext.
- Propagating Cipher Block Chaining (PCBC): a variation of CBC that is not commonly used.
- Cipher Feedback (CFB): a self-synchronizing streaming mode of operation.
- Output Feedback (OFB): a simple synchronous streaming mode of operation.
- Counter (CTR): a streaming mode of operation that allows random access on encryption/decryption.
- Galois/Counter Mode (GCM) and GMAC: improvement of CTR with added authentication. It can also be used for message authentication only.

Backlinks

📝 Galois/Counter Mode (GCM) and GMAC
📝 Counter (CTR)
📝 Output Feedback (OFB)
📝 Cipher Feedback (CFB)
📝 Propagating Cipher Block Chaining (PCBC)
📝 Padding (Encryption)
📝 Initialization Vector
📝 Cipher Block Chaining (CBC)
📝 Electronic Codebook (ECB)
📝 § Cryptography