📝Cipher Feedback (CFB)

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§ Cryptography

• CFB is a block cipher mode of operation and is a close relative to CBC.

• CFB make a block cipher into a self-synchronizing stream cipher.

  • CFB can self-synchronize if multiple of block size is lost.

  • If you need to allow dropping bits or bytes, you need to encrypt one bit or byte at a time (CFB can be combined with shift registers to do that).

• CFB does not require padding.

• Encryption algorithm:

  • IV is encrypted and xored with the plaintext.

  • The resulting ciphertext is the IV for the next block.

• Decryption algorithm:

  • IV is encrypted and xored with the ciphertext.

  • Ciphertext is used as IV for the next block.

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• 📝 Block cipher mode of operation