doc/man3/EVP_SignInit.pod - third_party/openssl - Git at Google

 =pod

 =head1 NAME

 EVP_SignInit, EVP_SignInit_ex, EVP_SignUpdate,
 EVP_SignFinal_ex, 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_ex(EVP_MD_CTX *ctx, unsigned char *md, unsigned int *s,
                       EVP_PKEY *pkey, OSSL_LIB_CTX *libctx, const char *propq);
  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);

 =head1 DESCRIPTION

 The EVP signature routines are a high-level interface to digital
 signatures.

 EVP_SignInit_ex() sets up signing context I<ctx> to use digest
 I<type> from B<ENGINE> I<impl>. I<ctx> must be created with
 EVP_MD_CTX_new() before calling this function.

 EVP_SignUpdate() hashes I<cnt> bytes of data at I<d> into the
 signature context I<ctx>. This function can be called several times on the
 same I<ctx> to include additional data.

 EVP_SignFinal_ex() signs the data in I<ctx> using the private key
 I<pkey> and places the signature in I<sig>. The library context I<libctx> and
 property query I<propq> are used when creating a context to use with the key
 I<pkey>. I<sig> must be at least C<EVP_PKEY_get_size(pkey)> bytes in size.
 I<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 I<s>, at most C<EVP_PKEY_get_size(pkey)>
 bytes will be written.

 EVP_SignFinal() is similar to EVP_SignFinal_ex() but uses default
 values of NULL for the library context I<libctx> and the property query I<propq>.

 EVP_SignInit() initializes a signing context I<ctx> to use the default
 implementation of digest I<type>.

 =head1 RETURN VALUES

 EVP_SignInit_ex(), EVP_SignUpdate(), EVP_SignFinal_ex() and
 EVP_SignFinal() return 1 for success and 0 for failure.

 The error codes can be obtained by L<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.

 When signing with DSA private keys the random number generator must be seeded.
 If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to
 external circumstances (see L<RAND(7)>), the operation will fail.
 This requirement does not hold 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_free() 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_PKEY_get_size(3)>, L<EVP_PKEY_get_bits(3)>,
 L<EVP_PKEY_get_security_bits(3)>,
 L<EVP_VerifyInit(3)>,
 L<EVP_DigestInit(3)>,
 L<evp(7)>, L<HMAC(3)>, L<MD2(3)>,
 L<MD5(3)>, L<MDC2(3)>, L<RIPEMD160(3)>,
 L<SHA1(3)>, L<openssl-dgst(1)>

 =head1 HISTORY

 The function EVP_SignFinal_ex() was added in OpenSSL 3.0.

 =head1 COPYRIGHT

 Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

 Licensed under the Apache License 2.0 (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
	=pod

	=head1 NAME

	EVP_SignInit, EVP_SignInit_ex, EVP_SignUpdate,
	EVP_SignFinal_ex, 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_ex(EVP_MD_CTX ctx, unsigned char md, unsigned int *s,
	EVP_PKEY pkey, OSSL_LIB_CTX libctx, const char *propq);
	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);

	=head1 DESCRIPTION

	The EVP signature routines are a high-level interface to digital
	signatures.

	EVP_SignInit_ex() sets up signing context I<ctx> to use digest
	I<type> from B<ENGINE> I<impl>. I<ctx> must be created with
	EVP_MD_CTX_new() before calling this function.

	EVP_SignUpdate() hashes I<cnt> bytes of data at I<d> into the
	signature context I<ctx>. This function can be called several times on the
	same I<ctx> to include additional data.

	EVP_SignFinal_ex() signs the data in I<ctx> using the private key
	I<pkey> and places the signature in I<sig>. The library context I<libctx> and
	property query I<propq> are used when creating a context to use with the key
	I<pkey>. I<sig> must be at least C<EVP_PKEY_get_size(pkey)> bytes in size.
	I<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 I<s>, at most C<EVP_PKEY_get_size(pkey)>
	bytes will be written.

	EVP_SignFinal() is similar to EVP_SignFinal_ex() but uses default
	values of NULL for the library context I<libctx> and the property query I<propq>.

	EVP_SignInit() initializes a signing context I<ctx> to use the default
	implementation of digest I<type>.

	=head1 RETURN VALUES

	EVP_SignInit_ex(), EVP_SignUpdate(), EVP_SignFinal_ex() and
	EVP_SignFinal() return 1 for success and 0 for failure.

	The error codes can be obtained by L<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.

	When signing with DSA private keys the random number generator must be seeded.
	If the automatic seeding or reseeding of the OpenSSL CSPRNG fails due to
	external circumstances (see L<RAND(7)>), the operation will fail.
	This requirement does not hold 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_free() 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_PKEY_get_size(3)>, L<EVP_PKEY_get_bits(3)>,
	L<EVP_PKEY_get_security_bits(3)>,
	L<EVP_VerifyInit(3)>,
	L<EVP_DigestInit(3)>,
	L<evp(7)>, L<HMAC(3)>, L<MD2(3)>,
	L<MD5(3)>, L<MDC2(3)>, L<RIPEMD160(3)>,
	L<SHA1(3)>, L<openssl-dgst(1)>

	=head1 HISTORY

	The function EVP_SignFinal_ex() was added in OpenSSL 3.0.

	=head1 COPYRIGHT

	Copyright 2000-2021 The OpenSSL Project Authors. All Rights Reserved.

	Licensed under the Apache License 2.0 (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