doc/crypto/md5.pod

   1 =pod
   2
   3 =head1 NAME
   4
   5 MD2, MD5, MD2_Init, MD2_Update, MD2_Final, MD5_Init, MD5_Update,
   6 MD5_Final - MD2 and MD5 hash functions
   7
   8 =head1 SYNOPSIS
   9
  10  #include <openssl/md2.h>
  11
  12  unsigned char *MD2(const unsigned char *d, unsigned long n,
  13                   unsigned char *md);
  14
  15  void MD2_Init(MD2_CTX *c);
  16  void MD2_Update(MD2_CTX *c, const unsigned char *data,
  17                   unsigned long len);
  18  void MD2_Final(unsigned char *md, MD2_CTX *c);
  19
  20
  21  #include <openssl/md5.h>
  22
  23  unsigned char *MD5(const unsigned char *d, unsigned long n,
  24                   unsigned char *md);
  25
  26  void MD5_Init(MD5_CTX *c);
  27  void MD5_Update(MD5_CTX *c, const unsigned char *data,
  28                   unsigned long len);
  29  void MD5_Final(unsigned char *md, MD5_CTX *c);
  30
  31 =head1 DESCRIPTION
  32
  33 MD2 and MD5 are cryptographic hash functions with a 128 bit output.
  34
  35 MD2() and MD5() compute the MD2 and MD5 message digest of the B<n>
  36 bytes at B<d> and place it in B<md> (which must have space for
  37 MD2_DIGEST_LENGTH == MD5_DIGEST_LENGTH == 16 bytes of output). If
  38 B<md> is NULL, the digest is placed in a static array.
  39
  40 The following functions may be used if the message is not completely
  41 stored in memory:
  42
  43 MD2_Init() initializes a B<MD2_CTX> structure.
  44
  45 MD2_Update() can be called repeatedly with chunks of the message to
  46 be hashed (B<len> bytes at B<data>).
  47
  48 MD2_Final() places the message digest in B<md>, which must have space
  49 for MD2_DIGEST_LENGTH == 16 bytes of output, and erases the B<MD2_CTX>.
  50
  51 MD5_Init(), MD5_Update() and MD5_Final() are analogous using an
  52 B<MD5_CTX> structure.
  53
  54 =head1 NOTE
  55
  56 MD2 and MD5 are recommended only for compatibility with existing
  57 applications. In new applications, SHA-1 or RIPEMD-160 should be
  58 preferred.
  59
  60 =head1 RETURN VALUES
  61
  62 MD2() and MD5() return pointers to the hash value.
  63
  64 MD2_Init(), MD2_Update() MD2_Final(), MD5_Init(), MD5_Update() and
  65 MD5_Final() do not return values.
  66
  67 =head1 CONFORMING TO
  68
  69 RFC 1319, RFC 1321
  70
  71 =head1 SEE ALSO
  72
  73 L<sha(3)|sha(3)>, L<ripemd(3)|ripemd(3)>
  74
  75 =head1 HISTORY
  76
  77 MD2(), MD2_Init(), MD2_Update() MD2_Final(), MD5(), MD5_Init(),
  78 MD5_Update() and MD5_Final() are available in all versions of SSLeay
  79 and OpenSSL.
  80
  81 =cut