=pod

=head1 NAME

MD5, MD5_Init, MD5_Update, MD5_Final - MD5 hash functions

=head1 SYNOPSIS

 #include <openssl/md5.h>

 unsigned char *MD5(const unsigned char *d, unsigned long n,
                  unsigned char *md);

 int MD5_Init(MD5_CTX *c);
 int MD5_Update(MD5_CTX *c, const void *data,
                  unsigned long len);
 int MD5_Final(unsigned char *md, MD5_CTX *c);

=head1 DESCRIPTION

MD5 is a cryptographic hash function with a 128 bit output.

MD5() computes the MD5 message digest of the B<n> bytes at B<d> and
places it in B<md> (which must have space for MD5_DIGEST_LENGTH == 16
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:

Applications should use the higher level functions
L<EVP_DigestInit(3)|EVP_DigestInit(3)>
etc. instead of calling the hash functions directly.

=head1 NOTE

MD5 is recommended only for compatibility with legacy applications.
In new applications, SHA-2 should be preferred.

=head1 RETURN VALUES

MD5() returns a pointer to the hash value.

MD5_Init(), MD5_Update(), and MD5_Final() return 1 for success, 0
otherwise.

=head1 CONFORMING TO

RFC 1321

=head1 SEE ALSO

L<EVP_DigestInit(3)|EVP_DigestInit(3)>

=head1 HISTORY

MD5(), MD5_Init(), MD5_Update() and MD5_Final() are available in all
versions of OpenSSL.

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