Signature Algorithm
The cryptographic algorithm used to sign this certificate
The Signature Algorithm specifies the cryptographic method used by the Certificate Authority to digitally sign the certificate. This algorithm ensures the certificate's integrity and authenticity by creating a digital signature that can be verified using the CA's public key. Common signature algorithms include RSA with SHA-256 (RSA-SHA256), ECDSA with SHA-256 (ECDSA-SHA256), and RSA with SHA-384.
The algorithm consists of two parts: the hashing algorithm (like SHA-256) that creates a fixed-size digest of the certificate data, and the encryption algorithm (like RSA or ECDSA) that encrypts this digest using the CA's private key. Modern certificates predominantly use SHA-256 as the hashing function, as older algorithms like SHA-1 have been deprecated due to security vulnerabilities.
ECDSA signatures are becoming increasingly popular due to their smaller size and better performance compared to RSA while providing equivalent security levels.
Where You'll See This Term
This term commonly appears in:
- SSL certificate details pages
- Certificate Authority validation processes
- SSL configuration documentation
- Security audit reports
- Certificate management interfaces