Reference for SHA-1.

[openssl.git] / doc / crypto / sha.pod

diff --git a/doc/crypto/sha.pod b/doc/crypto/sha.pod
index 65852568a329c1701db1514305308677422e81e3..defc442808d51d036c6b9cf9c72cb127ddb6069a 100644 (file)
--- a/doc/crypto/sha.pod
+++ b/doc/crypto/sha.pod
@@ -2,14 +2,14 @@
 
 =head1 NAME
 
-sha - Secure Hash Algorithm
+SHA1, SHA1_Init, SHA1_Update, SHA1_Final - Secure Hash Algorithm
 
 =head1 SYNOPSIS
 
  #include <openssl/sha.h>
 
  unsigned char *SHA1(const unsigned char *d, unsigned long n,
-                     unsigned char *md);
+                  unsigned char *md);
 
  void SHA1_Init(SHA_CTX *c);
  void SHA1_Update(SHA_CTX *c, const unsigned char *data,
@@ -21,16 +21,46 @@ sha - Secure Hash Algorithm
 SHA-1 (Secure Hash Algorithm) is a cryptographic hash function with a
 160 bit output.
 
+SHA1() computes the SHA-1 message digest of the B<n>
+bytes at B<d> and places it in B<md> (which must have space for
+SHA_DIGEST_LENGTH == 20 bytes of output). If B<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 B<SHA_CTX> structure.
+
+SHA1_Update() can be called repeatedly with chunks of the message to
+be hashed (B<len> bytes at B<data>).
+
+SHA1_Final() places the message digest in B<md>, which must have space
+for SHA_DIGEST_LENGTH == 20 bytes of output, and erases the B<SHA_CTX>.
+
 The predecessor of SHA-1, SHA, is also implemented, but it should be
 used only when backward compatibility is required.
 
+=head1 RETURN VALUES
+
+SHA1() returns a pointer to the hash value. 
+
+SHA1_Init(), SHA1_Update() and SHA1_Final() do not return values.
+
 =head1 CONFORMING TO
 
-US Federal Information Processing Standard FIPS 180 (Secure Hash
-Standard), ANSI X9.30
+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
 
 =head1 SEE ALSO
 
-ripemd(3), SHA1(3), SHA1_Init(3)
+L<ripemd(3)|ripemd(3)>
+
+=head1 HISTORY
+
+SHA1(), SHA1_Init(), SHA1_Update() and SHA1_Final() are available in all
+versions of SSLeay and OpenSSL.
 
 =cut