Hashing algorithms Secure hash algorithms can be used to support implementation of keyed-hash message authentication Generally, Hash functions are used to speed up data comparison tasks — such as finding items in a database, detecting duplicated or similar records in a large file or system. Algorithm Name References Approved Use Required Key Length SHA-n A secure hash algorithm that produces a hash size of “n” e.g.: (SHA 224, 256 ,384,512) [SHA] All hashing purposes n ≥ 256 MD5 Message Digest v5 [RFC 1321] All hashing purposes The typical 128-bit state Note: SHAn SHOULD be used unless this is not technically possible. MD5 usage should be limited to systems not supporting SHA family. 55 NATIONAL INFORMATION ASSURANCE MANUAL