libressl-SHA13
Secure hash algorithm
Usage
Crypto Library (libcrypto, -lcrypto)
#include <openssl/sha.h>
unsigned char *
SHA1(const unsigned char *d, size_t n, unsigned char *md);
int
SHA1_Init(SHA_CTX *c);
int
SHA1_Update(SHA_CTX *c, const void *data, size_t len);
int
SHA1_Final(unsigned char *md, SHA_CTX *c);
unsigned char *
SHA224(const unsigned char *d, size_t n, unsigned char *md);
int
SHA224_Init(SHA256_CTX *c);
int
SHA224_Update(SHA256_CTX *c, const void *data, size_t len);
int
SHA224_Final(unsigned char *md, SHA256_CTX *c);
unsigned char *
SHA256(const unsigned char *d, size_t n, unsigned char *md);
int
SHA256_Init(SHA256_CTX *c);
int
SHA256_Update(SHA256_CTX *c, const void *data, size_t len);
int
SHA256_Final(unsigned char *md, SHA256_CTX *c);
unsigned char *
SHA384(const unsigned char *d, size_t n, unsigned char *md);
int
SHA384_Init(SHA512_CTX *c);
int
SHA384_Update(SHA512_CTX *c, const void *data, size_t len);
int
SHA384_Final(unsigned char *md, SHA512_CTX *c);
unsigned char *
SHA512(const unsigned char *d, size_t n, unsigned char *md);
int
SHA512_Init(SHA512_CTX *c);
int
SHA512_Update(SHA512_CTX *c, const void *data, size_t len);
int
SHA512_Final(unsigned char *md, SHA512_CTX *c);
Overview
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.
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.
The SHA224, SHA256, SHA384, and SHA512 families of functions operate in the same way as the SHA1 functions. Note that SHA224 and SHA256 use a SHA256_CTX object instead of SHA_CTX, and SHA384 and SHA512 use SHA512_CTX. The buffer md must have space for the output from the SHA variant being used: SHA224_DIGEST_LENGTH, SHA256_DIGEST_LENGTH, SHA384_DIGEST_LENGTH, or SHA512_DIGEST_LENGTH bytes.
Applications should use the higher level functions EVP_DigestInit(3) etc. instead of calling the hash functions directly.
Return values
SHA1(), SHA224(), SHA256(), SHA384(), and SHA512() return a pointer to the hash value. The other functions return 1 for success or 0 otherwise.
Caveats
Other implementations allow md in SHA1(), SHA224(), SHA256(), SHA384(), and SHA512() to be NULL and return a static array, which is not thread safe.