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SHA(3)
NAME
  SHA, 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 );

  void SHA1_Init(
	  SHA_CTX *c );

  void SHA1_Update(
	  SHA_CTX *c, const void *data, unsigned long len );

  void SHA1_Final(
	  unsigned char *md, SHA_CTX *c );

DESCRIPTION
  SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a
  160-bit output.

  The SHA1() function 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 can be used if the message is not completely stored
  in memory:

  The SHA1_Init() function initializes a SHA_CTX structure.

  The SHA1_Update() function can be called repeatedly with chunks of the
  message to be hashed (len bytes at data).

  The SHA1_Final() function 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, such as
  EVP_DigestInit(), 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
  The SHA1() function returns a pointer to the hash value.

  The SHA1_Init(), SHA1_Update(), and SHA1_Final() functions do not return
  values.

HISTORY
  The SHA1(), SHA1_Init(), SHA1_Update(), and SHA1_Final() functions are
  available in all versions of SSLeay and OpenSSL.

  SHA conforms to US Federal Information Processing Standard FIPS PUB 180
  (Secure Hash Standard). SHA-1 conforms to US Federal Information Processing
  Standard FIPS PUB 180-1 (Secure Hash Standard), ANSI X9.30

SEE ALSO
  Functions: ripemd(3), hmac(3), EVP_DigestInit(3)

Index for Section 3

Alphabetical listing for S

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