D2I_PKCS8PRIVATEKEY_BIO(3ossl)

📦
version 3.5.9 · 8 versions
, in fedora 43, fedora 44

💅 D2I_PKCS8PRIVATEKEY_BIO 💅

okay bestie, gather round, because this one is literally the OpenSSL manual page for D2I_PKCS8PRIVATEKEY_BIO(3ossl) and it's giving cryptography main character energy. it lives in the OpenSSL docs, section 3ossl, and it's all about yeeting private keys into and out of PKCS#8 format. let's get into it 🫶

✨ 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 💖

like, six whole functions. a whole squad. obsessed.

🌸 SYNOPSIS 🌸

#include <openssl/pem.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, const EVP_PKEY *x, const EVP_CIPHER *enc,
                            char *kstr, int klen,
                            pem_password_cb *cb, void *u);

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

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

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

no cap, that's a lot of parameters. but every single one matters, so we keep them all. periodt. 💅

🦋 DESCRIPTION 🦋

so the PKCS#8 functions encode and decode private keys in PKCS#8 format, and they use both PKCS#5 v1.5 and PKCS#5 v2.0 password based encryption algorithms. versatile queen behavior honestly. 👑

and here's the tea: other than the use of DER as opposed to PEM, these functions are identical to the corresponding PEM function as described in PEM_read_PrivateKey(3). so if you already know that one, you basically know this one. iykyk. ✨

🎀 NOTES 🎀

  • these functions are currently the only way to store encrypted private keys using DER format. the moment. the only one. 🔥
  • currently all the functions use BIOs or FILE pointers, and there are no functions which work directly on memory. ngl that's a little annoying, but it can be readily worked around by converting the buffers to memory BIOs — see BIO_s_mem(3) for the details. problem solved, bestie. 🧚
  • these functions make no assumption regarding the pass phrase received from the password callback. it will simply be treated as a byte sequence. so don't come at it with your fancy string expectations, it's just bytes and it's thriving. 💜

⭐ RETURN VALUES ⭐

  • d2i_PKCS8PrivateKey_bio() and d2i_PKCS8PrivateKey_fp() return a valid EVP_PKEY structure, or NULL if an error occurred. so like… check for NULL, okay? don't be out here raw-dogging error handling. 😭
  • i2d_PKCS8PrivateKey_bio(), i2d_PKCS8PrivateKey_fp(), i2d_PKCS8PrivateKey_nid_bio() and i2d_PKCS8PrivateKey_nid_fp() return 1 on success or 0 on error. classic 1-or-0 situation, very demure, very mindful. 🌈

💀 SEE ALSO 💀

go read those too, bestie. staying informed is self care. 🍓

Copyright 2002-2018 The OpenSSL Project Authors. All Rights Reserved.

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 <https://www.openssl.org/source/license.html>.

okay real talk — this is legal stuff, so i'm keeping it word for word. don't skip it, it's important. 🙈

and that's the whole page, bestie!! this was OpenSSL 3.5.9, dated 2026-09-29, straight from the D2I_PKCS8PRIVATEKEY_BIO(3ossl) manual. go forth and encrypt your DER private keys responsibly. mwah. 💖✨🎀🦋🌸💅🫶

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