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sha1init(3ext) [opensolaris man page]

sha1(3EXT)						    Extended Library Functions							sha1(3EXT)

NAME
sha1, SHA1Init, SHA1Update, SHA1Final - SHA1 digest functions SYNOPSIS
cc [ flag ... ] file ... -lmd [ library ... ] #include <sha1.h> void SHA1Init(SHA1_CTX *context); void SHA1Update(SHA1_CTX *context, unsigned char *input, unsigned int inlen); void SHA1Final(unsigned char *output, SHA1_CTX *context); DESCRIPTION
The SHA1 functions implement the SHA1 message-digest algorithm. The algorithm takes as input a message of arbitrary length and produces a 200-bit "fingerprint" or "message digest" as output. The SHA1 message-digest algorithm is intended for digital signature applications in which large files are "compressed" in a secure manner before being encrypted with a private (secret) key under a public-key cryptosystem such as RSA. SHA1Init(), SHA1Update(), SHA1Final() The SHA1Init(), SHA1Update(), and SHA1Final() functions allow a SHA1 digest to be computed over multiple message blocks. Between blocks, the state of the SHA1 computation is held in an SHA1 context structure allocated by the caller. A complete digest computation consists of calls to SHA1 functions in the following order: one call to SHA1Init(), one or more calls to SHA1Update(), and one call to SHA1Final(). The SHA1Init() function initializes the SHA1 context structure pointed to by context. The SHA1Update() function computes a partial SHA1 digest on the inlen-byte message block pointed to by input, and updates the SHA1 con- text structure pointed to by context accordingly. The SHA1Final() function generates the final SHA1 digest, using the SHA1 context structure pointed to by context. The 16-bit SHA1 digest is written to output. After a call to SHA1Final(), the state of the context structure is undefined. It must be reinitialized with SHA1Init() before it can be used again. SECURITY
The SHA1 algorithm is also believed to have some weaknesses. Migration to one of the SHA2 algorithms-including SHA256, SHA386 or SHA512-is highly recommended when compatibility with data formats and on wire protocols is permitted. RETURN VALUES
These functions do not return a value. EXAMPLES
Example 1 Authenticate a message found in multiple buffers The following is a sample function that authenticates a message found in multiple buffers. The calling function provides an authentication buffer to contain the result of the SHA1 digest. #include <sys/types.h> #include <sys/uio.h> #include <sha1.h> int AuthenticateMsg(unsigned char *auth_buffer, struct iovec *messageIov, unsigned int num_buffers) { SHA1_CTX sha1_context; unsigned int i; SHA1Init(&sha1_context); for(i=0; i<num_buffers; i++) { SHA1Update(&sha1_context, messageIov->iov_base, messageIov->iov_len); messageIov += sizeof(struct iovec); } SHA1Final(auth_buffer, &sha1_context); return 0; } ATTRIBUTES
See attributes(5) for descriptions of the following attributes: +-----------------------------+-----------------------------+ | ATTRIBUTE TYPE | ATTRIBUTE VALUE | +-----------------------------+-----------------------------+ |Interface Stability |Committed | +-----------------------------+-----------------------------+ |MT-Level |MT-Safe | +-----------------------------+-----------------------------+ SEE ALSO
sha2(3EXT), libmd(3LIB) RFC 1374 SunOS 5.11 13 Nov 2007 sha1(3EXT)

Check Out this Related Man Page

SHA1(3) 						   BSD Library Functions Manual 						   SHA1(3)

NAME
SHA1Init, SHA1Update, SHA1Final, SHA1Transform, SHA1End, SHA1File, SHA1Data -- calculate the NIST Secure Hash Algorithm SYNOPSIS
#include <sys/types.h> #include <sha1.h> void SHA1Init(SHA1_CTX *context); void SHA1Update(SHA1_CTX *context, const uint8_t *data, u_int len); void SHA1Final(uint8_t digest[20], SHA1_CTX *context); void SHA1Transform(uint32_t state[5], uint8_t buffer[64]); char * SHA1End(SHA1_CTX *context, char *buf); char * SHA1File(char *filename, char *buf); char * SHA1Data(uint8_t *data, size_t len, char *buf); DESCRIPTION
The SHA1 functions implement the NIST Secure Hash Algorithm (SHA-1), FIPS PUB 180-1. SHA-1 is used to generate a condensed representation of a message called a message digest. The algorithm takes a message less than 2^64 bits as input and produces a 160-bit digest suitable for use as a digital signature. The SHA1 functions are considered to be more secure than the md4(3) and md5(3) functions with which they share a similar interface. The SHA1Init() function initializes a SHA1_CTX context for use with SHA1Update(), and SHA1Final(). The SHA1Update() function adds data of length len to the SHA1_CTX specified by context. SHA1Final() is called when all data has been added via SHA1Update() and stores a message digest in the digest parameter. When a null pointer is passed to SHA1Final() as first argument only the final padding will be applied and the current context can still be used with SHA1Update(). The SHA1Transform() function is used by SHA1Update() to hash 512-bit blocks and forms the core of the algorithm. Most programs should use the interface provided by SHA1Init(), SHA1Update() and SHA1Final() instead of calling SHA1Transform() directly. The SHA1End() function is a front end for SHA1Final() which converts the digest into an ASCII representation of the 160 bit digest in hexa- decimal. The SHA1File() function calculates the digest for a file and returns the result via SHA1End(). If SHA1File() is unable to open the file a NULL pointer is returned. The SHA1Data() function calculates the digest of an arbitrary string and returns the result via SHA1End(). For each of the SHA1End(), SHA1File(), and SHA1Data() functions the buf parameter should either be a string of at least 41 characters in size or a NULL pointer. In the latter case, space will be dynamically allocated via malloc(3) and should be freed using free(3) when it is no longer needed. EXAMPLES
The follow code fragment will calculate the digest for the string "abc" which is ``0xa9993e36476816aba3e25717850c26c9cd0d89d''. SHA1_CTX sha; uint8_t results[20]; char *buf; int n; buf = "abc"; n = strlen(buf); SHA1Init(&sha); SHA1Update(&sha, (uint8_t *)buf, n); SHA1Final(results, &sha); /* Print the digest as one long hex value */ printf("0x"); for (n = 0; n < 20; n++) printf("%02x", results[n]); putchar(' '); Alternately, the helper functions could be used in the following way: SHA1_CTX sha; uint8_t output[41]; char *buf = "abc"; printf("0x%s", SHA1Data(buf, strlen(buf), output)); SEE ALSO
md5(1), md4(3), md5(3) J. Burrows, The Secure Hash Standard, FIPS PUB 180-1. HISTORY
The SHA-1 functions appeared in NetBSD 1.4. AUTHORS
This implementation of SHA-1 was written by Steve Reid. The SHA1End(), SHA1File(), and SHA1Data() helper functions are derived from code written by Poul-Henning Kamp. BUGS
This implementation of SHA-1 has not been validated by NIST and as such is not in official compliance with the standard. If a message digest is to be copied to a multi-byte type (ie: an array of five 32-bit integers) it will be necessary to perform byte swapping on little endian machines such as the i386, alpha, and VAX. BSD
July 10, 1997 BSD
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