SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm

#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);

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 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.

SHA1() returns a pointer to the hash value.

SHA1_Init(), SHA1_Update() and SHA1_Final() return 1 for success, 0 otherwise.

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