RSA_BLINDING_ON(3ossl)

📦 version 3.5.0, in opensuse-leap 16.0

💖 RSA_BLINDING_ON 💖 (the 3ossl manual, bestie)

okay so bestie, this page is all about keeping RSA operations from getting clocked by timing attacks. It’s giving security glam 💅, but also it’s a deprecated-girlie situation, so pay attention.

✨ NAME ✨

RSA_blinding_on, RSA_blinding_off — protect the RSA operation from timing attacks 🛡️

🎀 SYNOPSIS 🎀

#include <openssl/rsa.h>

The following functions have been 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 RSA_blinding_on(RSA *rsa, BN_CTX *ctx);

void RSA_blinding_off(RSA *rsa);

🌸 DESCRIPTION 🌸

All of the functions described on this page are deprecated. 🫠

RSA is vulnerable to timing attacks. In a setup where attackers can measure the time of RSA decryption or signature operations, blinding must be used to protect the RSA operation from that attack. Like, literally must. No cap. 🔥

RSA_blinding_on() turns blinding on for key rsa and generates a random blinding factor. ctx is NULL or a preallocated and initialized BN_CTX.

RSA_blinding_off() turns blinding off and frees the memory used for the blinding factor. bye-bye, blinding factor 👋

⭐ RETURN VALUES ⭐

  • RSA_blinding_on() returns 1 on success, and 0 if an error occurred.
  • RSA_blinding_off() returns no value.

🦋 HISTORY 🦋

All of these functions were deprecated in OpenSSL 3.0. It’s giving “iconic but retired” energy 💀✨

Copyright 2000-2021 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.

This page is from OpenSSL 3.5.0, dated 2026-09-25 — mwah, take care of your RSA ops 💋💖

📦 where this page comes from