=head1 NAME
-EVP_SignInit, EVP_SignUpdate, EVP_SignFinal - EVP signing functions
+EVP_PKEY_size,
+EVP_SignInit, EVP_SignInit_ex, EVP_SignUpdate, EVP_SignFinal - EVP signing
+functions
=head1 SYNOPSIS
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);
+ 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);
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.
+B<type> from ENGINE B<impl>. B<ctx> must be created with
+EVP_MD_CTX_new() 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>. If the B<s> parameter is not NULL
-then the number of bytes of data written (i.e. the length of the signature)
+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 parameter, 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.
+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 error codes can be obtained by L<ERR_get_error(3)|ERR_get_error(3)>.
+The error codes can be obtained by L<ERR_get_error(3)>.
=head1 NOTES
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)>.
+algorithms and associated public key algorithms appears in
+L<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
=head1 BUGS
-Older versions of this documentation wrongly stated that calls to
+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<digest(1)|digest(1)>
+L<EVP_VerifyInit(3)>,
+L<EVP_DigestInit(3)>, L<err(3)>,
+L<evp(3)>, L<hmac(3)>, L<md2(3)>,
+L<md5(3)>, L<mdc2(3)>, L<ripemd(3)>,
+L<sha(3)>, L<dgst(1)>
-=head1 HISTORY
+=head1 COPYRIGHT
-EVP_SignInit(), EVP_SignUpdate() and EVP_SignFinal() are
-available in all versions of SSLeay and OpenSSL.
+Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
-EVP_SignInit_ex() was added in OpenSSL 0.9.7
+Licensed under the OpenSSL license (the "License"). You may not use
+this file except in compliance with the License. You can obtain a copy
+in the file LICENSE in the source distribution or at
+L<https://www.openssl.org/source/license.html>.
=cut
projects / openssl.git / blobdiff