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Security Fundamentals & Crypto · Intermediate

Twofish

Symmetric block cipher with a 128-bit block and keys up to 256 bits; an AES competition finalist.

Definition

Twofish was designed by Bruce Schneier and colleagues and reached the final round of the AES selection. It is unpatented and supported by tools such as VeraCrypt and some VPNs. It has no practical known breaks.

Example

VeraCrypt lets users choose AES, Serpent, or Twofish, or cascades of them.

Exam tip

Distinguish from Blowfish by block size (128 vs 64 bits).

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