diff options
Diffstat (limited to 'doc/crypto/EVP_SignInit.pod')
-rw-r--r-- | doc/crypto/EVP_SignInit.pod | 107 |
1 files changed, 0 insertions, 107 deletions
diff --git a/doc/crypto/EVP_SignInit.pod b/doc/crypto/EVP_SignInit.pod deleted file mode 100644 index c63d6b339318..000000000000 --- a/doc/crypto/EVP_SignInit.pod +++ /dev/null @@ -1,107 +0,0 @@ -=pod - -=head1 NAME - -EVP_SignInit, EVP_SignInit_ex, EVP_SignUpdate, EVP_SignFinal - EVP signing -functions - -=head1 SYNOPSIS - - #include <openssl/evp.h> - - int EVP_SignInit_ex(EVP_MD_CTX *ctx, const EVP_MD *type, ENGINE *impl); - int EVP_SignUpdate(EVP_MD_CTX *ctx, const void *d, unsigned int cnt); - int EVP_SignFinal(EVP_MD_CTX *ctx,unsigned char *sig,unsigned int *s, EVP_PKEY *pkey); - - void EVP_SignInit(EVP_MD_CTX *ctx, const EVP_MD *type); - - int EVP_PKEY_size(EVP_PKEY *pkey); - -=head1 DESCRIPTION - -The EVP signature routines are a high level interface to digital -signatures. - -EVP_SignInit_ex() sets up signing context B<ctx> to use digest -B<type> from ENGINE B<impl>. B<ctx> must be initialized with -EVP_MD_CTX_init() before calling this function. - -EVP_SignUpdate() hashes B<cnt> bytes of data at B<d> into the -signature context B<ctx>. This function can be called several times on the -same B<ctx> to include additional data. - -EVP_SignFinal() signs the data in B<ctx> using the private key B<pkey> and -places the signature in B<sig>. B<sig> must be at least EVP_PKEY_size(pkey) -bytes in size. B<s> is an OUT paramter, and not used as an IN parameter. -The number of bytes of data written (i.e. the length of the signature) -will be written to the integer at B<s>, at most EVP_PKEY_size(pkey) bytes -will be written. - -EVP_SignInit() initializes a signing context B<ctx> to use the default -implementation of digest B<type>. - -EVP_PKEY_size() returns the maximum size of a signature in bytes. The actual -signature returned by EVP_SignFinal() may be smaller. - -=head1 RETURN VALUES - -EVP_SignInit_ex(), EVP_SignUpdate() and EVP_SignFinal() return 1 -for success and 0 for failure. - -EVP_PKEY_size() returns the maximum size of a signature in bytes. - -The error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>. - -=head1 NOTES - -The B<EVP> interface to digital signatures should almost always be used in -preference to the low level interfaces. This is because the code then becomes -transparent to the algorithm used and much more flexible. - -Due to the link between message digests and public key algorithms the correct -digest algorithm must be used with the correct public key type. A list of -algorithms and associated public key algorithms appears in -L<EVP_DigestInit(3)|EVP_DigestInit(3)>. - -When signing with DSA private keys the random number generator must be seeded -or the operation will fail. The random number generator does not need to be -seeded for RSA signatures. - -The call to EVP_SignFinal() internally finalizes a copy of the digest context. -This means that calls to EVP_SignUpdate() and EVP_SignFinal() can be called -later to digest and sign additional data. - -Since only a copy of the digest context is ever finalized the context must -be cleaned up after use by calling EVP_MD_CTX_cleanup() or a memory leak -will occur. - -=head1 BUGS - -Older versions of this documentation wrongly stated that calls to -EVP_SignUpdate() could not be made after calling EVP_SignFinal(). - -Since the private key is passed in the call to EVP_SignFinal() any error -relating to the private key (for example an unsuitable key and digest -combination) will not be indicated until after potentially large amounts of -data have been passed through EVP_SignUpdate(). - -It is not possible to change the signing parameters using these function. - -The previous two bugs are fixed in the newer EVP_SignDigest*() function. - -=head1 SEE ALSO - -L<EVP_VerifyInit(3)|EVP_VerifyInit(3)>, -L<EVP_DigestInit(3)|EVP_DigestInit(3)>, L<err(3)|err(3)>, -L<evp(3)|evp(3)>, L<hmac(3)|hmac(3)>, L<md2(3)|md2(3)>, -L<md5(3)|md5(3)>, L<mdc2(3)|mdc2(3)>, L<ripemd(3)|ripemd(3)>, -L<sha(3)|sha(3)>, L<dgst(1)|dgst(1)> - -=head1 HISTORY - -EVP_SignInit(), EVP_SignUpdate() and EVP_SignFinal() are -available in all versions of SSLeay and OpenSSL. - -EVP_SignInit_ex() was added in OpenSSL 0.9.7. - -=cut |