SHA1(3)                    Library Functions Manual                    SHA1(3)

NAME
     SHA1, SHA1_Init, SHA1_Update, SHA1_Final, SHA224, SHA224_Init,
     SHA224_Update, SHA224_Final, SHA256, SHA256_Init, SHA256_Update,
     SHA256_Final, SHA384, SHA384_Init, SHA384_Update, SHA384_Final, SHA512,
     SHA512_Init, SHA512_Update, SHA512_Final - Secure Hash Algorithm

SYNOPSIS
     #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);

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, which is
     not thread safe.

     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.

     The predecessor of SHA-1, SHA, is also implemented, but it should be used
     only when backward compatibility is required.

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.

SEE ALSO
     EVP_DigestInit(3), HMAC(3), RIPEMD160(3)

STANDARDS
     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

HISTORY
     SHA1(), SHA1_Init(), SHA1_Update(), and SHA1_Final() first appeared in
     SSLeay 0.5.1 and have been available since OpenBSD 2.4.

     The other functions first appeared in OpenSSL 0.9.8 and have been
     available since OpenBSD 4.5.

Linux 6.8.2-arch2-1             March 27, 2018             Linux 6.8.2-arch2-1