EVP_PKEY_cmp.pod revision 306195 
1=pod
2
3=head1 NAME
4
5EVP_PKEY_copy_parameters, EVP_PKEY_missing_parameters, EVP_PKEY_cmp_parameters, EVP_PKEY_cmp - public key parameter and comparison functions
6
7=head1 SYNOPSIS
8
9 #include <openssl/evp.h>
10
11 int EVP_PKEY_missing_parameters(const EVP_PKEY *pkey);
12 int EVP_PKEY_copy_parameters(EVP_PKEY *to, const EVP_PKEY *from);
13
14 int EVP_PKEY_cmp_parameters(const EVP_PKEY *a, const EVP_PKEY *b);
15 int EVP_PKEY_cmp(const EVP_PKEY *a, const EVP_PKEY *b);
16
17=head1 DESCRIPTION
18
19The function EVP_PKEY_missing_parameters() returns 1 if the public key
20parameters of B<pkey> are missing and 0 if they are present or the algorithm
21doesn't use parameters.
22
23The function EVP_PKEY_copy_parameters() copies the parameters from key
24B<from> to key B<to>. An error is returned if the parameters are missing in
25B<from> or present in both B<from> and B<to> and mismatch. If the parameters
26in B<from> and B<to> are both present and match this function has no effect.
27
28The function EVP_PKEY_cmp_parameters() compares the parameters of keys
29B<a> and B<b>.
30
31The function EVP_PKEY_cmp() compares the public key components and paramters
32(if present) of keys B<a> and B<b>.
33
34=head1 NOTES
35
36The main purpose of the functions EVP_PKEY_missing_parameters() and
37EVP_PKEY_copy_parameters() is to handle public keys in certificates where the
38parameters are sometimes omitted from a public key if they are inherited from
39the CA that signed it.
40
41Since OpenSSL private keys contain public key components too the function
42EVP_PKEY_cmp() can also be used to determine if a private key matches
43a public key.
44
45=head1 RETURN VALUES
46
47The function EVP_PKEY_missing_parameters() returns 1 if the public key
48parameters of B<pkey> are missing and 0 if they are present or the algorithm
49doesn't use parameters.
50
51These functions EVP_PKEY_copy_parameters() returns 1 for success and 0 for
52failure.
53
54The function EVP_PKEY_cmp_parameters() and EVP_PKEY_cmp() return 1 if the
55keys match, 0 if they don't match, -1 if the key types are different and
56-2 if the operation is not supported.
57
58=head1 SEE ALSO
59
60L<EVP_PKEY_CTX_new(3)|EVP_PKEY_CTX_new(3)>,
61L<EVP_PKEY_keygen(3)|EVP_PKEY_keygen(3)> 
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63=cut
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