1=pod
2
3=head1 NAME
4
5d2i_PrivateKey, d2i_PublicKey, d2i_AutoPrivateKey,
6i2d_PrivateKey, i2d_PublicKey,
7d2i_PrivateKey_bio, d2i_PrivateKey_fp
8- decode and encode functions for reading and saving EVP_PKEY structures
9
10=head1 SYNOPSIS
11
12 #include <openssl/evp.h>
13
14 EVP_PKEY *d2i_PrivateKey(int type, EVP_PKEY **a, const unsigned char **pp,
15                          long length);
16 EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **a, const unsigned char **pp,
17                         long length);
18 EVP_PKEY *d2i_AutoPrivateKey(EVP_PKEY **a, const unsigned char **pp,
19                              long length);
20 int i2d_PrivateKey(EVP_PKEY *a, unsigned char **pp);
21 int i2d_PublicKey(EVP_PKEY *a, unsigned char **pp);
22
23 EVP_PKEY *d2i_PrivateKey_bio(BIO *bp, EVP_PKEY **a);
24 EVP_PKEY *d2i_PrivateKey_fp(FILE *fp, EVP_PKEY **a)
25
26=head1 DESCRIPTION
27
28d2i_PrivateKey() decodes a private key using algorithm B<type>. It attempts to
29use any key specific format or PKCS#8 unencrypted PrivateKeyInfo format. The
30B<type> parameter should be a public key algorithm constant such as
31B<EVP_PKEY_RSA>. An error occurs if the decoded key does not match B<type>.
32d2i_PublicKey() does the same for public keys.
33
34d2i_AutoPrivateKey() is similar to d2i_PrivateKey() except it attempts to
35automatically detect the private key format.
36
37i2d_PrivateKey() encodes B<key>. It uses a key specific format or, if none is
38defined for that key type, PKCS#8 unencrypted PrivateKeyInfo format.
39i2d_PublicKey() does the same for public keys.
40
41These functions are similar to the d2i_X509() functions; see L<d2i_X509(3)>.
42
43=head1 NOTES
44
45All these functions use DER format and unencrypted keys. Applications wishing
46to encrypt or decrypt private keys should use other functions such as
47d2i_PKCS8PrivateKey() instead.
48
49If the B<*a> is not NULL when calling d2i_PrivateKey() or d2i_AutoPrivateKey()
50(i.e. an existing structure is being reused) and the key format is PKCS#8
51then B<*a> will be freed and replaced on a successful call.
52
53To decode a key with type B<EVP_PKEY_EC>, d2i_PublicKey() requires B<*a> to be
54a non-NULL EVP_PKEY structure assigned an EC_KEY structure referencing the proper
55EC_GROUP.
56
57=head1 RETURN VALUES
58
59The d2i_PrivateKey(), d2i_AutoPrivateKey(), d2i_PrivateKey_bio(), d2i_PrivateKey_fp(),
60and d2i_PublicKey() functions return a valid B<EVP_KEY> structure or B<NULL> if an
61error occurs. The error code can be obtained by calling L<ERR_get_error(3)>.
62
63i2d_PrivateKey() and i2d_PublicKey() return the number of bytes successfully
64encoded or a negative value if an error occurs. The error code can be obtained
65by calling L<ERR_get_error(3)>.
66
67=head1 SEE ALSO
68
69L<crypto(7)>,
70L<d2i_PKCS8PrivateKey_bio(3)>
71
72=head1 COPYRIGHT
73
74Copyright 2017-2019 The OpenSSL Project Authors. All Rights Reserved.
75
76Licensed under the OpenSSL license (the "License").  You may not use
77this file except in compliance with the License.  You can obtain a copy
78in the file LICENSE in the source distribution or at
79L<https://www.openssl.org/source/license.html>.
80
81=cut
82