RSA_METH_NEW(3SSL)
💖 RSA_METH_NEW 💖
okay bestie, so this page is officially RSA_METH_NEW(3SSL) in the OpenSSL fam, and it's literally the whole ✨ method-building ✨ toolkit for RSA. 🎀
✨ NAME ✨
so basically all of these are routines to build up RSA methods 🔧 — like, you're constructing your own RSA_METHOD, a little custom blueprint for how RSA operations should behave. Meet the whole squad:
RSA_meth_get0_app_data,RSA_meth_set0_app_dataRSA_meth_new,RSA_meth_free,RSA_meth_dupRSA_meth_get0_name,RSA_meth_set1_nameRSA_meth_get_flags,RSA_meth_set_flagsRSA_meth_get_pub_enc,RSA_meth_set_pub_encRSA_meth_get_pub_dec,RSA_meth_set_pub_decRSA_meth_get_priv_enc,RSA_meth_set_priv_encRSA_meth_get_priv_dec,RSA_meth_set_priv_decRSA_meth_get_mod_exp,RSA_meth_set_mod_expRSA_meth_get_bn_mod_exp,RSA_meth_set_bn_mod_expRSA_meth_get_init,RSA_meth_set_initRSA_meth_get_finish,RSA_meth_set_finishRSA_meth_get_sign,RSA_meth_set_signRSA_meth_get_verify,RSA_meth_set_verifyRSA_meth_get_keygen,RSA_meth_set_keygenRSA_meth_get_multi_prime_keygen,RSA_meth_set_multi_prime_keygen
it's giving builder-pattern but make it cryptography 💅 — and the description of the whole assignment is just: Routines to build up RSA methods. periodt.
✨ SYNOPSIS ✨
first things first, you gotta pull in the header bestie:
#include <openssl/rsa.h>🚨 THE BIG WARNING 🚨 — the following functions have been deprecated since OpenSSL 3.0, and can be hidden entirely by definingOPENSSL_API_COMPATwith a suitable version value, seeopenssl_user_macros(7). like, they're not gone, they're just on thin ice 🧊 so pls be aware.
here's the whole cast, verbatim, no cap:
RSA_METHOD *RSA_meth_new(const char *name, int flags);
void RSA_meth_free(RSA_METHOD *meth);
RSA_METHOD *RSA_meth_dup(const RSA_METHOD *meth);
const char *RSA_meth_get0_name(const RSA_METHOD *meth);
int RSA_meth_set1_name(RSA_METHOD *meth, const char *name);
int RSA_meth_get_flags(const RSA_METHOD *meth);
int RSA_meth_set_flags(RSA_METHOD *meth, int flags);
void *RSA_meth_get0_app_data(const RSA_METHOD *meth);
int RSA_meth_set0_app_data(RSA_METHOD *meth, void *app_data);
int (*RSA_meth_get_pub_enc(const RSA_METHOD *meth))(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding);
int RSA_meth_set_pub_enc(RSA_METHOD *rsa,
int (*pub_enc)(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,
int padding));
int (*RSA_meth_get_pub_dec(const RSA_METHOD *meth))
(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding);
int RSA_meth_set_pub_dec(RSA_METHOD *rsa,
int (*pub_dec)(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,
int padding));
int (*RSA_meth_get_priv_enc(const RSA_METHOD *meth))(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,
int padding);
int RSA_meth_set_priv_enc(RSA_METHOD *rsa,
int (*priv_enc)(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding));
int (*RSA_meth_get_priv_dec(const RSA_METHOD *meth))(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa,
int padding);
int RSA_meth_set_priv_dec(RSA_METHOD *rsa,
int (*priv_dec)(int flen, const unsigned char *from,
unsigned char *to, RSA *rsa, int padding));
/* Can be null */
int (*RSA_meth_get_mod_exp(const RSA_METHOD *meth))(BIGNUM *r0, const BIGNUM *i,
RSA *rsa, BN_CTX *ctx);
int RSA_meth_set_mod_exp(RSA_METHOD *rsa,
int (*mod_exp)(BIGNUM *r0, const BIGNUM *i, RSA *rsa,
BN_CTX *ctx));
/* Can be null */
int (*RSA_meth_get_bn_mod_exp(const RSA_METHOD *meth))(BIGNUM *r, const BIGNUM *a,
const BIGNUM *p, const BIGNUM *m,
BN_CTX *ctx, BN_MONT_CTX *m_ctx);
int RSA_meth_set_bn_mod_exp(RSA_METHOD *rsa,
int (*bn_mod_exp)(BIGNUM *r, const BIGNUM *a,
const BIGNUM *p, const BIGNUM *m,
BN_CTX *ctx, BN_MONT_CTX *m_ctx));
/* called at new */
int (*RSA_meth_get_init(const RSA_METHOD *meth) (RSA *rsa);
int RSA_meth_set_init(RSA_METHOD *rsa, int (*init (RSA *rsa));
/* called at free */
int (*RSA_meth_get_finish(const RSA_METHOD *meth))(RSA *rsa);
int RSA_meth_set_finish(RSA_METHOD *rsa, int (*finish)(RSA *rsa));
int (*RSA_meth_get_sign(const RSA_METHOD *meth))(int type, const unsigned char *m,
unsigned int m_length,
unsigned char *sigret,
unsigned int *siglen, const RSA *rsa);
int RSA_meth_set_sign(RSA_METHOD *rsa,
int (*sign)(int type, const unsigned char *m,
unsigned int m_length, unsigned char *sigret,
unsigned int *siglen, const RSA *rsa));
int (*RSA_meth_get_verify(const RSA_METHOD *meth))(int dtype, const unsigned char *m,
unsigned int m_length,
const unsigned char *sigbuf,
unsigned int siglen, const RSA *rsa);
int RSA_meth_set_verify(RSA_METHOD *rsa,
int (*verify)(int dtype, const unsigned char *m,
unsigned int m_length,
const unsigned char *sigbuf,
unsigned int siglen, const RSA *rsa));
int (*RSA_meth_get_keygen(const RSA_METHOD *meth))(RSA *rsa, int bits, BIGNUM *e,
BN_GENCB *cb);
int RSA_meth_set_keygen(RSA_METHOD *rsa,
int (*keygen)(RSA *rsa, int bits, BIGNUM *e,
BN_GENCB *cb));
int (*RSA_meth_get_multi_prime_keygen(const RSA_METHOD *meth))(RSA *rsa, int bits,
int primes, BIGNUM *e,
BN_GENCB *cb);
int RSA_meth_set_multi_prime_keygen(RSA_METHOD *meth,
int (*keygen) (RSA *rsa, int bits,
int primes, BIGNUM *e,
BN_GENCB *cb));notice how some of these are marked /* Can be null */ 🙈 and some are like /* called at new */ and /* called at free */ — hold that thought, we're getting into it. and yes bestie, the getters return whole function pointers, which is giving very int (*...)(...) energy, iconic honestly 🌈
more parts coming, don't go anywhere 🫶
🦋 DESCRIPTION 🦋
okay bestie, gather round, because this is the part where I have to tell you something devastating: all of the functions on this page are deprecated 😭 like, every single one. the glow-up replacement? applications should instead use the OSSL_PROVIDER APIs. periodt. that's the tea. 💅
so the RSA_METHOD type is a structure used for the provision of custom RSA implementations. it's giving "build your own crypto backend" energy. it provides a set of functions used by OpenSSL for the implementation of the various RSA capabilities. think of it as a little toolbox 🧰 of function pointers that OpenSSL picks up and goes "slay, I'll use these."
RSA_meth_new() creates a new RSA_METHOD structure. ✨ It should be given a unique name and a set of flags. The name should be a NULL terminated string, which will be duplicated and stored in the RSA_METHOD object. It is the callers responsibility to free the original string. The flags will be used during the construction of a new RSA object based on this RSA_METHOD. Any new RSA object will have those flags set by default. so like, your flags are the vibe you're passing down to every baby RSA object born from this method. 👑
RSA_meth_dup() creates a duplicate copy of the RSA_METHOD object passed as a parameter. This might be useful for creating a new RSA_METHOD based on an existing one, but with some differences. it's the "same outfit, different accessories" move 💖
RSA_meth_free() destroys an RSA_METHOD structure and frees up any memory associated with it. If the argument is NULL, nothing is done. no drama, no crash, just vibes. 🫶
RSA_meth_get0_name() will return a pointer to the name of this RSA_METHOD. This is a pointer to the internal name string and so should not be freed by the caller. please don't touch it, it's not yours, it's hers. 🙈 RSA_meth_set1_name() sets the name of the RSA_METHOD to name. The string is duplicated and the copy is stored in the RSA_METHOD structure, so the caller remains responsible for freeing the memory associated with the name.
RSA_meth_get_flags() returns the current value of the flags associated with this RSA_METHOD. RSA_meth_set_flags() provides the ability to set these flags. flags on, flags off, you're in control. 🎀
The functions RSA_meth_get0_app_data() and RSA_meth_set0_app_data() provide the ability to associate implementation specific data with the RSA_METHOD. It is the application's responsibility to free this data before the RSA_METHOD is freed via a call to RSA_meth_free(). so like, clean up your own mess before you leave the group chat. 💀
RSA_meth_get_sign() and RSA_meth_set_sign() get and set the function used for creating an RSA signature respectively. This function will be called in response to the application calling RSA_sign(). The parameters for the function have the same meaning as for RSA_sign(). signature time, bestie. ✍️
RSA_meth_get_verify() and RSA_meth_set_verify() get and set the function used for verifying an RSA signature respectively. This function will be called in response to the application calling RSA_verify(). The parameters for the function have the same meaning as for RSA_verify(). trust but verify, literally. 🔍
RSA_meth_get_mod_exp() and RSA_meth_set_mod_exp() get and set the function used for CRT computations.
RSA_meth_get_bn_mod_exp() and RSA_meth_set_bn_mod_exp() get and set the function used for CRT computations, specifically the following value:
r = a ^ p mod mBoth the mod_exp() and bn_mod_exp() functions are called by the default OpenSSL method during encryption, decryption, signing and verification. math girlies stay winning. 🧮✨
RSA_meth_get_init() and RSA_meth_set_init() get and set the function used for creating a new RSA instance respectively. This function will be called in response to the application calling RSA_new() (if the current default RSA_METHOD is this one) or RSA_new_method(). The RSA_new() and RSA_new_method() functions will allocate the memory for the new RSA object, and a pointer to this newly allocated structure will be passed as a parameter to the function. This function may be NULL. birth of a new RSA object, iconic. 👶👑
RSA_meth_get_finish() and RSA_meth_set_finish() get and set the function used for destroying an instance of an RSA object respectively. This function will be called in response to the application calling RSA_free(). A pointer to the RSA to be destroyed is passed as a parameter. The destroy function should be used for RSA implementation specific clean up. The memory for the RSA itself should not be freed by this function. This function may be NULL. it's giving "you handle the cleanup, I'll handle the memory, we don't overlap." 🧹
RSA_meth_get_keygen() and RSA_meth_set_keygen() get and set the function used for generating a new RSA key pair respectively. This function will be called in response to the application calling RSA_generate_key_ex(). The parameter for the function has the same meaning as for RSA_generate_key_ex(). new keys, who dis? 🔑💖
RSA_meth_get_multi_prime_keygen() and RSA_meth_set_multi_prime_keygen() get and set the function used for generating a new multi-prime RSA key pair respectively. This function will be called in response to the application calling RSA_generate_multi_prime_key(). The parameter for the function has the same meaning as for RSA_generate_multi_prime_key(). multi-prime, multi-fabulous. 🌈
RSA_meth_get_pub_enc(), RSA_meth_set_pub_enc(), RSA_meth_get_pub_dec(), RSA_meth_set_pub_dec(), RSA_meth_get_priv_enc(), RSA_meth_set_priv_enc(), RSA_meth_get_priv_dec(), RSA_meth_set_priv_dec() get and set the functions used for public and private key encryption and decryption. These functions will be called in response to the application calling RSA_public_encrypt(), RSA_private_decrypt(), RSA_private_encrypt() and RSA_public_decrypt() and take the same parameters as those. the whole enc/dec foursome, all here, all accounted for. 💅
🫶 RETURN VALUES 🫶
RSA_meth_new() and RSA_meth_dup() return the newly allocated RSA_METHOD object or NULL on failure. so check for NULL, bestie, don't get played. 😭
RSA_meth_get0_name() and RSA_meth_get_flags() return the name and flags associated with the RSA_METHOD respectively.
All other RSA_meth_get_*() functions return the appropriate function pointer that has been set in the RSA_METHOD, or NULL if no such pointer has yet been set. so like, if nobody set it, you get NULL. that's just how it is. 🤷♀️
RSA_meth_set1_name and all RSA_meth_set_*() functions return 1 on success or 0 on failure. one for slay, zero for nay. ✨
👀 SEE ALSO 👀
RSA_new(3)RSA_generate_key_ex(3)RSA_sign(3)RSA_set_method(3)RSA_size(3)RSA_get0_key(3)RSA_generate_multi_prime_key(3)
go read those too, iykyk. 💜
📜 HISTORY 📜
All of these functions were deprecated in OpenSSL 3.0. rip bozo, but also, growth. 🌱
RSA_meth_get_multi_prime_keygen() and RSA_meth_set_multi_prime_keygen() were added in OpenSSL 1.1.1.
Other functions described here were added in OpenSSL 1.1.0.
so like, 1.1.0 walked so 1.1.1 could run, and then 3.0 said "deprecated, bestie." 💀
⚖️ COPYRIGHT ⚖️
Copyright 2016-2024 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>.
and that's the page, bestie 🎀 this was RSA_METH_NEW(3SSL) from OpenSSL 4.0.3, dated 2026-09-29 — so yes, future-dated, main character energy only. go forth and be careful with those deprecated function pointers, fr fr. 💖✨🦋
📦 where this page comes from
- ubuntu stonking: libssl-doc 4.0.3-1ubuntu1 · Apache-2.0
- 💖 girlified by deepseek-ai/DeepSeek-V4.1-Flash on : a language model's rewrite of the original, under its terms