=head1 NAME
DH_generate_parameters_ex, DH_generate_parameters,
-DH_check - generate and check Diffie-Hellman parameters
+DH_check, DH_check_params,
+DH_check_ex, DH_check_params_ex, DH_check_pub_key_ex
+- generate and check Diffie-Hellman
+parameters
=head1 SYNOPSIS
int DH_generate_parameters_ex(DH *dh, int prime_len, int generator, BN_GENCB *cb);
int DH_check(DH *dh, int *codes);
+ int DH_check_params(DH *dh, int *codes);
-Deprecated:
+ int DH_check_ex(const DH *dh);
+ int DH_check_params_ex(const DH *dh);
+ int DH_check_pub_key_ex(const DH *dh, const BIGNUM *pub_key);
+
+Deprecated since OpenSSL 0.9.8, can be hidden entirely by defining
+B<OPENSSL_API_COMPAT> with a suitable version value, see
+L<openssl_user_macros(7)>:
- #if OPENSSL_API_COMPAT < 0x00908000L
DH *DH_generate_parameters(int prime_len, int generator,
- void (*callback)(int, int, void *), void *cb_arg);
- #endif
+ void (*callback)(int, int, void *), void *cb_arg);
=head1 DESCRIPTION
DH_generate_parameters_ex() generates Diffie-Hellman parameters that can
be shared among a group of users, and stores them in the provided B<DH>
structure. The pseudo-random number generator must be
-seeded prior to calling DH_generate_parameters().
+seeded before calling it.
+The parameters generated by DH_generate_parameters_ex() should not be used in
+signature schemes.
B<prime_len> is the length in bits of the safe prime to be generated.
B<generator> is a small number E<gt> 1, typically 2 or 5.
of the key generation. If B<cb> is not B<NULL>, it will be
called as described in L<BN_generate_prime(3)> while a random prime
number is generated, and when a prime has been found, B<BN_GENCB_call(cb, 3, 0)>
-is called. See L<BN_generate_prime(3)> for information on
+is called. See L<BN_generate_prime_ex(3)> for information on
the BN_GENCB_call() function.
+DH_generate_parameters() is similar to DH_generate_prime_ex() but
+expects an old-style callback function; see
+L<BN_generate_prime(3)> for information on the old-style callback.
+
+DH_check_params() confirms that the B<p> and B<g> are likely enough to
+be valid.
+This is a lightweight check, if a more thorough check is needed, use
+DH_check().
+The value of B<*codes> is updated with any problems found.
+If B<*codes> is zero then no problems were found, otherwise the
+following bits may be set:
+
+=over 4
+
+=item DH_CHECK_P_NOT_PRIME
+
+The parameter B<p> has been determined to not being an odd prime.
+Note that the lack of this bit doesn't guarantee that B<p> is a
+prime.
+
+=item DH_NOT_SUITABLE_GENERATOR
+
+The generator B<g> is not suitable.
+Note that the lack of this bit doesn't guarantee that B<g> is
+suitable, unless B<p> is known to be a strong prime.
+
+=back
+
DH_check() confirms that the Diffie-Hellman parameters B<dh> are valid. The
value of B<*codes> is updated with any problems found. If B<*codes> is zero then
no problems were found, otherwise the following bits may be set:
=back
-=head1 RETURN VALUES
-
-DH_generate_parameters_ex() and DH_check() return 1 if the check could be
-performed, 0 otherwise.
+DH_check_ex(), DH_check_params() and DH_check_pub_key_ex() are similar to
+DH_check() and DH_check_params() respectively, but the error reasons are added
+to the thread's error queue instead of provided as return values from the
+function.
-DH_generate_parameters() (deprecated) returns a pointer to the DH structure, or
-NULL if the parameter generation fails.
+=head1 RETURN VALUES
-The error codes can be obtained by L<ERR_get_error(3)>.
+DH_generate_parameters_ex(), DH_check() and DH_check_params() return 1
+if the check could be performed, 0 otherwise.
-=head1 NOTES
+DH_generate_parameters() returns a pointer to the DH structure or NULL if
+the parameter generation fails.
-DH_generate_parameters_ex() and DH_generate_parameters() may run for several
-hours before finding a suitable prime.
+DH_check_ex(), DH_check_params() and DH_check_pub_key_ex() return 1 if the
+check is successful, 0 for failed.
-The parameters generated by DH_generate_parameters_ex() and DH_generate_parameters()
-are not to be used in signature schemes.
+The error codes can be obtained by L<ERR_get_error(3)>.
=head1 SEE ALSO
L<DH_new(3)>, L<ERR_get_error(3)>, L<RAND_bytes(3)>,
L<DH_free(3)>
+=head1 HISTORY
+
+DH_generate_parameters() was deprecated in OpenSSL 0.9.8; use
+DH_generate_parameters_ex() instead.
+
=head1 COPYRIGHT
-Copyright 2000-2016 The OpenSSL Project Authors. All Rights Reserved.
+Copyright 2000-2018 The OpenSSL Project Authors. All Rights Reserved.
-Licensed under the OpenSSL license (the "License"). You may not use
+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>.
projects / openssl.git / blobdiff