RSA_PRINT(3ossl)

💅 RSA_PRINT — bestie edition (3ossl, OpenSSL)

okay so. gather round. this is RSA_PRINT(3ossl), and it's the page about printing cryptographic parameters, but like... the ✨old✨ way. it's giving deprecated-but-still-documented, iykyk.

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🌸 NAME 🌸

RSA_print, RSA_print_fp, DSAparams_print, DSAparams_print_fp, DSA_print, DSA_print_fp, DHparams_print, DHparams_print_fp — literally just print cryptographic parameters 💖

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✨ SYNOPSIS ✨

first up, the RSA girlies:

#include <openssl/rsa.h>

bestie alert!! the functions below have been deprecated since OpenSSL 3.0, and you can hide them entirely by defining OPENSSL_API_COMPAT with a suitable version value — go read openssl_user_macros(7) for the deets 👀

int RSA_print(BIO *bp, const RSA *x, int offset);
int RSA_print_fp(FILE *fp, const RSA *x, int offset);

then the DSA section, new include, who dis:

#include <openssl/dsa.h>

same warning, no cap these ones are also deprecated since OpenSSL 3.0, hideable the same way with OPENSSL_API_COMPAT — again, openssl_user_macros(7) is your girl 🫶

int DSAparams_print(BIO *bp, const DSA *x);
int DSAparams_print_fp(FILE *fp, const DSA *x);
int DSA_print(BIO *bp, const DSA *x, int offset);
int DSA_print_fp(FILE *fp, const DSA *x, int offset);

and finally the DH corner of the group chat:

#include <openssl/dh.h>

yes, these too deprecated since OpenSSL 3.0, and can be hidden entirely by defining OPENSSL_API_COMPAT with a suitable version value, see openssl_user_macros(7) 💀

int DHparams_print(BIO *bp, DH *x);
int DHparams_print_fp(FILE *fp, const DH *x);

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🦋 DESCRIPTION 🦋

okay so the headline here: all of the functions described on this page are deprecated. like, every single one. the whole squad. 😭

applications should instead use EVP_PKEY_print_params(3) and EVP_PKEY_print_private(3). that's the glow-up, periodt.

so what did the old ones even do? they printed a human-readable hexadecimal output of the components of the RSA key, or the DSA parameters, or the DSA key, or the DH parameters — and it goes out to bp or fp 💫

and the output lines? they get indented by offset spaces. cute little indent, very demure, very mindful.

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👑 RETURN VALUES 👑

• DSAparams_print(), DSAparams_print_fp(), DSA_print(), and DSA_print_fp() — return 1 for success, and 0 or a negative value for failure 🫠
• DHparams_print() and DHparams_print_fp() — return 1 on success, 0 on error 🥲

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🎀 SEE ALSO 🎀

• EVP_PKEY_print_params(3)
• EVP_PKEY_print_private(3)
• BN_bn2bin(3)

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🌈 HISTORY 🌈

all of these functions were deprecated in OpenSSL 3.0. that's the whole history section. short, iconic, devastating 💅

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💖 COPYRIGHT 💖

Copyright 2000-2020 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>.

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and that's the whole page, bestie — this one's from OpenSSL 3.5.9, dated 2026-09-29, and it lives in the 3ossl manual section. now go use EVP_PKEY_print_params(3) like the main character you are ✨🦋💜