Chapter

The Salsa20 Family of Stream Ciphers

DOI: 10.1007/978-3-540-68351-3_8

ABSTRACT Salsa20 is a family of 256-bit stream ciphers designed in 2005 and submitted to eSTREAM, the ECRYPT Stream Cipher Project.
Salsa20 has progressed to the third round of eSTREAM without any changes. The 20-round stream cipher Salsa20/20 is consistently
faster than AES and is recommended by the designer for typical cryptographic applications. The reduced-round ciphers Salsa20/12
and Salsa20/8 are among the fastest 256-bit stream ciphers available and are recommended for applications where speed is more
important than confidence. The fastest known attacks use ≈ 2153 simple operations against Salsa20/7, ≈ 2249 simple operations against Salsa20/8, and ≈ 2255 simple operations against Salsa20/9, Salsa20/10, etc. In this paper, the Salsa20 designer presents Salsa20 and discusses
the decisions made in the Salsa20 design.

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