Short: SHA-1 message digest generator Author: lay@dspnet.hu (Lay András) Uploader: lay dspnet hu (Lay András) Type: util/crypt Architecture: m68k-amigaos What is SHA-1? -------------- SHA-1SUM is a small utility that allows you to calculate checksums of any file using the Secure Hash Algorithm, like the "MD5 Message Digest Algorithm", but SHA-1 is more secure. It is written in 100% assembly, because it's very fast. (2MB file length, 3 seconds on a 68040/25.) The algorithm taken from Federal Information Processing Standards Publication 180-1, and tested with three examples described in this material. You can check this on: http://www.dice.ucl.ac.be/crypto/standards/fips/html/fip180-1.htm Usage: ------ SHA-1SUM Notes: ------ The program reads the whole file into the memory, that's why there must be as much free RAM as long the file is. Lay András Some words from FIP180-1: ------------------------- The Secure Hash Algorithm (SHA-1) is required for use with the Digital Signature Algorithm (DSA) as specified in the Digital Signature Standard (DSS) and whenever a secure hash algorithm is required for federal applications. For a message of length < 2^64 bits, the SHA-1 produces a 160-bit condensed representation of the message called a message digest. The message digest is used during generation of a signature for the message. The SHA-1 is also used to compute a message digest for the received version of the message during the process of verifying the signature. Any change to the message in transit will, with very high probability, result in a different message digest, and the signature will fail to verify. The SHA-1 is designed to have the following properties: it is computationally infeasible to find a message which corresponds to a given message digest, or to find two different messages which produce the same message digest. The SHA-1 is called secure because it is computationally infeasible to find a message which corresponds to a given message digest, or to find two different messages which produce the same message digest. Any change to a message in transit will, with very high probability, result in a different message digest, and the signature will fail to verify. SHA-1 is a technical revision of SHA (FIPS 180). A circular left shift operation has been added to the specifications in section 7, line b, page 9 of FIPS 180 and its equivalent in section 8, line c, page 10 of FIPS 180. This revision improves the security provided by this standard. The SHA-1 is based on principles similar to those used by Professor Ronald L. Rivest of MIT when designing the MD4 message digest algorithm ("The MD4 Message Digest Algorithm," Advances in Cryptology - CRYPTO '90 Proceedings, Springer-Verlag, 1991, pp. 303-311), and is closely modelled after that algorithm.