• Use "Validate Issuer Signing Request" tab to check certificate requests before sending to VISA CA for signing.

• Load the certificate request file or paste hex data, then click Validate to verify structure and format.

• Use "Validate Signed Issuer Public Key Data" tab to verify certificates received from VISA CA.

• Load or paste the signed certificate data, select a predefined CA key (VSDC CA V92/V94) or load a custom CA public key.

• Click Validate to verify the signature using RSA verification with the selected CA public key.

• Enable Debug mode to see detailed information about certificate structure, modulus, exponent, and validation steps.