Rust Requires Chilkat v11.0.0+

Verify an RSA Signature Against the Signed String

See more Apple Keychain Examples

Demonstrates how to validate an RSA Signature against the string that was signed. Rust

// Create the same string we previously signed in this example: 
// RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

let sb = chilkat::StringBuilder::new();
let crlf_line_ending = true;
for i in 0..=10 {
    let _ = sb.append_line("This is a test.", crlf_line_ending);
}

let base64_rsa_sig = "gWgpEXQqvXN6wh0MuFXPiw2xCb8cnmdizBT1TD1Tpm2GlJ8gnD59DGSj35GGXk1tM+mCOvMa2uW/9gmz8p6A90JLbn918i/2wKGvcde4wXnzPO7JADSNn2UwYzf3rp4/q/JrHv1GZETRJhABSFqTxOgdmdbEJQE/zijOSctCtQAM2CTb6t2BO8uHKSSUAwPH2cbeWxqsaVRLT4ruk5nZOxhoLgLMSjupiSzbE8zSTkkFOEHD+Mbb2xwg85AI0E4DsUnp+hLwwtS0blesgSyvtBY8oJODJeFcJsR7JDOTPdzHQHgJRl/2A4ij5xT91TpXy7ok43jhT6O9j7Q3qrafIQ==".to_string();

// Get the public key to be used for signature verification.
let pub_key = chilkat::PublicKey::new();
if pub_key.load_from_file("rsaKeys/chilkat-rsa-2048.pem").is_err() {
    println!("{}", pub_key.last_error_text());
    return;
}

let rsa = chilkat::Rsa::new();
if rsa.use_public_key(&pub_key).is_err() {
    println!("{}", rsa.last_error_text());
    return;
}

// Verify the string against the signature.
// We signed the utf-8 byte representation of the string, so we must indicate
// to also validate against the utf-8 byte representation.
rsa.set_charset("utf-8");
rsa.set_encoding_mode("base64");
let signed_string = sb.get_as_string().unwrap_or_default();

if rsa.verify_string_enc(&signed_string, "sha256", &base64_rsa_sig).is_err() {
    println!("{}", rsa.last_error_text());
    println!("Signature invalid.");
} else {
    println!("Signature valid.");
}