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RSA_BLINDING_ON(3) Library Functions Manual RSA_BLINDING_ON(3)

RSA_blinding_on, RSA_blinding_offprotect the RSA operation from timing attacks

#include <openssl/rsa.h>

RSA_blinding_on(RSA *rsa, BN_CTX *ctx);

RSA_blinding_off(RSA *rsa);

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.

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

() turns blinding off and frees the memory used for the blinding factor.

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


RSA_blinding_on() and RSA_blinding_off() first appeared in SSLeay 0.9.0 and have been available since OpenBSD 2.4.

July 26, 2023 OpenBSD-current