Updated: 2022/Sep/29

Please read Privacy Policy. It's for your privacy.

d2i_PrivateKey(3)                   OpenSSL                  d2i_PrivateKey(3)

       d2i_PrivateKey, d2i_PublicKey, d2i_AutoPrivateKey, i2d_PrivateKey,
       i2d_PublicKey, d2i_PrivateKey_bio, d2i_PrivateKey_fp - decode and
       encode functions for reading and saving EVP_PKEY structures

       libcrypto, -lcrypto

        #include <openssl/evp.h>

        EVP_PKEY *d2i_PrivateKey(int type, EVP_PKEY **a, const unsigned char **pp,
                                 long length);
        EVP_PKEY *d2i_PublicKey(int type, EVP_PKEY **a, const unsigned char **pp,
                                long length);
        EVP_PKEY *d2i_AutoPrivateKey(EVP_PKEY **a, const unsigned char **pp,
                                     long length);
        int i2d_PrivateKey(EVP_PKEY *a, unsigned char **pp);
        int i2d_PublicKey(EVP_PKEY *a, unsigned char **pp);

        EVP_PKEY *d2i_PrivateKey_bio(BIO *bp, EVP_PKEY **a);
        EVP_PKEY *d2i_PrivateKey_fp(FILE *fp, EVP_PKEY **a)

       d2i_PrivateKey() decodes a private key using algorithm type. It
       attempts to use any key specific format or PKCS#8 unencrypted
       PrivateKeyInfo format. The type parameter should be a public key
       algorithm constant such as EVP_PKEY_RSA. An error occurs if the decoded
       key does not match type.  d2i_PublicKey() does the same for public

       d2i_AutoPrivateKey() is similar to d2i_PrivateKey() except it attempts
       to automatically detect the private key format.

       i2d_PrivateKey() encodes key. It uses a key specific format or, if none
       is defined for that key type, PKCS#8 unencrypted PrivateKeyInfo format.
       i2d_PublicKey() does the same for public keys.

       These functions are similar to the d2i_X509() functions; see

       All these functions use DER format and unencrypted keys. Applications
       wishing to encrypt or decrypt private keys should use other functions
       such as d2i_PKCS8PrivateKey() instead.

       If the *a is not NULL when calling d2i_PrivateKey() or
       d2i_AutoPrivateKey() (i.e. an existing structure is being reused) and
       the key format is PKCS#8 then *a will be freed and replaced on a
       successful call.

       To decode a key with type EVP_PKEY_EC, d2i_PublicKey() requires *a to
       be a non-NULL EVP_PKEY structure assigned an EC_KEY structure
       referencing the proper EC_GROUP.

       The d2i_PrivateKey(), d2i_AutoPrivateKey(), d2i_PrivateKey_bio(),
       d2i_PrivateKey_fp(), and d2i_PublicKey() functions return a valid
       EVP_KEY structure or NULL if an error occurs. The error code can be
       obtained by calling ERR_get_error(3).

       i2d_PrivateKey() and i2d_PublicKey() return the number of bytes
       successfully encoded or a negative value if an error occurs. The error
       code can be obtained by calling ERR_get_error(3).

       crypto(7), d2i_PKCS8PrivateKey_bio(3)

       Copyright 2017-2019 The OpenSSL Project Authors. All Rights Reserved.

       Licensed under the OpenSSL license (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

1.1.1i                            2019-03-12                 d2i_PrivateKey(3)