=head1 NAME
-EVP_PKEY_size,
-EVP_SignInit, EVP_SignInit_ex, EVP_SignUpdate, EVP_SignFinal,
-EVP_PKEY_security_bits - EVP signing
-functions
+EVP_SignInit, EVP_SignInit_ex, EVP_SignUpdate,
+EVP_SignFinal_ex, 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_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);
- int EVP_PKEY_size(const EVP_PKEY *pkey);
- int EVP_PKEY_security_bits(const EVP_PKEY *pkey);
-
=head1 DESCRIPTION
-The EVP signature routines are a high level interface to digital
+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 created with
+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 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_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() 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.
+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 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>.
+will be written to the integer at I<s>, at most C<EVP_PKEY_get_size(pkey)>
+bytes will be written.
-EVP_PKEY_size() returns the maximum size of a signature in bytes. The actual
-signature returned by EVP_SignFinal() may be smaller.
+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_PKEY_security_bits() returns the number of security bits of the given B<pkey>,
-bits of security is defined in NIST SP800-57.
+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() and EVP_SignFinal() return 1
-for success and 0 for failure.
-
-EVP_PKEY_size() returns the maximum size of a signature in bytes.
+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)>.
-EVP_PKEY_security_bits() returns the number of security bits.
-
=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
+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.
+When signing with some private key types 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.
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.
+later to digest and sign additional data.cApplications may disable this
+behavior by setting the EVP_MD_CTX_FLAG_FINALISE context flag via
+L<EVP_MD_CTX_set_flags(3)>.
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.
+Note that not all providers support continuation, in case the selected
+provider does not allow to duplicate contexts EVP_SignFinal() will
+finalize the digest context and attempting to process additional data via
+EVP_SignUpdate() will result in an error.
+
=head1 BUGS
Older versions of this documentation wrongly stated that calls to
It is not possible to change the signing parameters using these function.
-The previous two bugs are fixed in the newer EVP_SignDigest*() function.
+The previous two bugs are fixed in the newer EVP_DigestSign*() functions.
=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 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2023 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
projects / openssl.git / blobdiff