sha1_init(3ssl) [linux man page]
sha(3SSL) OpenSSL sha(3SSL) NAME
SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm SYNOPSIS
#include <openssl/sha.h> unsigned char *SHA1(const unsigned char *d, unsigned long n, unsigned char *md); int SHA1_Init(SHA_CTX *c); int SHA1_Update(SHA_CTX *c, const void *data, unsigned long len); int SHA1_Final(unsigned char *md, SHA_CTX *c); DESCRIPTION
SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a 160 bit output. SHA1() computes the SHA-1 message digest of the n bytes at d and places it in md (which must have space for SHA_DIGEST_LENGTH == 20 bytes of output). If md is NULL, the digest is placed in a static array. The following functions may be used if the message is not completely stored in memory: SHA1_Init() initializes a SHA_CTX structure. SHA1_Update() can be called repeatedly with chunks of the message to be hashed (len bytes at data). SHA1_Final() places the message digest in md, which must have space for SHA_DIGEST_LENGTH == 20 bytes of output, and erases the SHA_CTX. Applications should use the higher level functions EVP_DigestInit(3) etc. instead of calling the hash functions directly. The predecessor of SHA-1, SHA, is also implemented, but it should be used only when backward compatibility is required. RETURN VALUES
SHA1() returns a pointer to the hash value. SHA1_Init(), SHA1_Update() and SHA1_Final() return 1 for success, 0 otherwise. CONFORMING TO
SHA: US Federal Information Processing Standard FIPS PUB 180 (Secure Hash Standard), SHA-1: US Federal Information Processing Standard FIPS PUB 180-1 (Secure Hash Standard), ANSI X9.30 SEE ALSO
ripemd(3), hmac(3), EVP_DigestInit(3) HISTORY
SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in all versions of SSLeay and OpenSSL. 1.0.1e 2013-02-11 sha(3SSL)
Check Out this Related Man Page
SHA(3) BSD Library Functions Manual SHA(3) NAME
SHA_Init, SHA_Update, SHA_Final, SHA_End, SHA_File, SHA_FileChunk, SHA_Data, SHA1_Init, SHA1_Update, SHA1_Final, SHA1_End, SHA1_File, SHA1_FileChunk, SHA1_Data -- calculate the FIPS 160 and 160-1 ``SHA'' message digests LIBRARY
Message Digest (MD4, MD5, etc.) Support Library (libmd, -lmd) SYNOPSIS
#include <sys/types.h> #include <sha.h> void SHA_Init(SHA_CTX *context); void SHA_Update(SHA_CTX *context, const unsigned char *data, size_t len); void SHA_Final(unsigned char digest[20], SHA_CTX *context); char * SHA_End(SHA_CTX *context, char *buf); char * SHA_File(const char *filename, char *buf); char * SHA_FileChunk(const char *filename, char *buf, off_t offset, off_t length); char * SHA_Data(const unsigned char *data, unsigned int len, char *buf); void SHA1_Init(SHA_CTX *context); void SHA1_Update(SHA_CTX *context, const unsigned char *data, size_t len); void SHA1_Final(unsigned char digest[20], SHA_CTX *context); char * SHA1_End(SHA_CTX *context, char *buf); char * SHA1_File(const char *filename, char *buf); char * SHA1_FileChunk(const char *filename, char *buf, off_t offset, off_t length); char * SHA1_Data(const unsigned char *data, unsigned int len, char *buf); DESCRIPTION
The SHA_ and SHA1_ functions calculate a 160-bit cryptographic checksum (digest) for any number of input bytes. A cryptographic checksum is a one-way hash function; that is, it is computationally impractical to find the input corresponding to a particular output. This net result is a ``fingerprint'' of the input-data, which does not disclose the actual input. SHA (or SHA-0) is the original Secure Hash Algorithm specified in FIPS 160. It was quickly proven insecure, and has been superseded by SHA-1. SHA-0 is included for compatibility purposes only. The SHA1_Init(), SHA1_Update(), and SHA1_Final() functions are the core functions. Allocate an SHA_CTX, initialize it with SHA1_Init(), run over the data with SHA1_Update(), and finally extract the result using SHA1_Final(). SHA1_End() is a wrapper for SHA1_Final() which converts the return value to a 41-character (including the terminating '