RSA_blinding_on(3ssl)

RSA_blinding_on3ssl

Protect the rsa operation from timing attacks

Usage

 #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);

Overview

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.

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.

Return values

RSA_blinding_on() returns 1 on success, and 0 if an error occurred.

RSA_blinding_off() returns no value.

Releases

13 releases since Debian 3.0 (Woody); the text changed 12 times.

  1. 3.0
  2. 3.1
  3. 4.0
  4. 5.0
  5. 6.0
  6. 7
  7. 8
  8. 9
  9. 10
  10. 11
  11. 12
  12. 13
  13. Arch

History

All of these functions were deprecated in OpenSSL 3.0.

From openssl 3.6.5-1 in Arch Linux 2026-11-01. Parsed by carta from the page's man source.