D2I_PKCS8PRIVATEKEY_BIO(3) | Library Functions Manual | D2I_PKCS8PRIVATEKEY_BIO(3)

# NAME

`d2i_PKCS8PrivateKey_bio`, `d2i_PKCS8PrivateKey_fp`, `i2d_PKCS8PrivateKey_bio`, `i2d_PKCS8PrivateKey_fp`, `i2d_PKCS8PrivateKey_nid_bio`, `i2d_PKCS8PrivateKey_nid_fp` — PKCS#8 format private key functions

# SYNOPSIS

library “libcrypto”
`#include <openssl/evp.h>`

EVP_PKEY *
`d2i_PKCS8PrivateKey_bio`(BIO *bp, EVP_PKEY **x, pem_password_cb *cb, void *u);

EVP_PKEY *
`d2i_PKCS8PrivateKey_fp`(FILE *fp, EVP_PKEY **x, pem_password_cb *cb, void *u);

int
`i2d_PKCS8PrivateKey_bio`(BIO *bp, EVP_PKEY *x, const EVP_CIPHER *enc, char *kstr, int klen, pem_password_cb *cb, void *u);

int
`i2d_PKCS8PrivateKey_fp`(FILE *fp, EVP_PKEY *x, const EVP_CIPHER *enc, char *kstr, int klen, pem_password_cb *cb, void *u);

int
`i2d_PKCS8PrivateKey_nid_bio`(BIO *bp, EVP_PKEY *x, int nid, char *kstr, int klen, pem_password_cb *cb, void *u);

int
`i2d_PKCS8PrivateKey_nid_fp`(FILE *fp, EVP_PKEY *x, int nid, char *kstr, int klen, pem_password_cb *cb, void *u);

# DESCRIPTION

The PKCS#8 functions encode and decode private keys in PKCS#8 format using both PKCS#5 v1.5 and PKCS#5 v2.0 password based encryption algorithms.

Other than the use of DER as opposed to PEM these functions are identical to the corresponding functions described in PEM_read_PrivateKey(3).

These functions are currently the only way to store encrypted private keys using DER format.

Currently all the functions use BIO or FILE pointers. There are no functions which work directly on memory, though this can be readily worked around by converting the buffers to memory BIOs; see BIO_s_mem(3) for details.

# RETURN VALUES

`d2i_PKCS8PrivateKey_bio`() and `d2i_PKCS8PrivateKey_fp`() return a EVP_PKEY object or `NULL` if an error occurs.

`i2d_PKCS8PrivateKey_bio`(), `i2d_PKCS8PrivateKey_fp`(), `i2d_PKCS8PrivateKey_nid_bio`(), and `i2d_PKCS8PrivateKey_nid_fp`() return 1 on success or 0 on error.

# SEE ALSO

d2i_X509_SIG(3), PEM_write_PKCS8PrivateKey(3), PKCS8_PRIV_KEY_INFO_new(3)

# HISTORY

These functions first appeared in OpenSSL 0.9.5 and have been available since OpenBSD 2.7.

# CAVEATS

Do not confuse these functions with i2d_PKCS8PrivateKeyInfo_bio(3) and i2d_PKCS8PrivateKeyInfo_fp(3), which write out private keys in unencrypted DER format.

June 8, 2025 | Debian