Rust Requires Chilkat v11.0.0+

RSA Encryption -- Same Key Different Results

See more RSA Examples

The RSA encryption algorithm produces different results for each call, even when encrypting the same data with the same key. Decryption however, will produce the correct results. This example demonstrates.

*** The reason this occurs is that RSA encryption uses PKCS1 v1.5 padding, and this padding scheme uses random bytes. It is random bytes in the padding that causes the result to be different each time.

Rust

// This example assumes the Chilkat API to have been previously unlocked.
// See Global Unlock Sample for sample code.

let rsa = chilkat::Rsa::new();

let pub_key_xml = "<RSAPublicKey><Modulus>xxyv1RDPU0MvfFIIa98HppXdcuI7zSu8uIqyGAy/VoxPvxZFX0acajznvjVRHipHbpcO6ryo2LwXUPf89qOqLb3Qd1lfD2ZnH+TQ6MZXNxfFRxTpTUd+tTR4EBYpd2t6kzq8ZRJYLdlviaMQQqUEwR54k7Op5HJYVKUcHIkP1xE=</Modulus><Exponent>AQAB</Exponent></RSAPublicKey>".to_string();

let priv_key_xml = "<RSAKeyValue><Modulus>xxyv1RDPU0MvfFIIa98HppXdcuI7zSu8uIqyGAy/VoxPvxZFX0acajznvjVRHipHbpcO6ryo2LwXUPf89qOqLb3Qd1lfD2ZnH+TQ6MZXNxfFRxTpTUd+tTR4EBYpd2t6kzq8ZRJYLdlviaMQQqUEwR54k7Op5HJYVKUcHIkP1xE=</Modulus><Exponent>AQAB</Exponent><P>4cpW9fvG99Jsz8/AO7PDHTl+pPRAglksrR2kClLV2g9DEeFe/bvmCxLUgMCJ+0eGQ1zA6aA7McKr13zTQ7jKpQ==</P><Q>4cCS/kFlq/P1ExF37Fkh4pCodOEGutepLEG7Q/KljT3ZGlAY+2l8fGu4f+hrkUuGoFl7NOMaJflULoPIgQaq/Q==</Q><DP>lkjcSsvzqh3YKRXJiLNkyf3rypV8noYGU4+oEOsDxilkZfFRDafUPUiiQrRk4ui/d/SzvozU+ZDuWfaOk8PatQ==</DP><DQ>SYCD25i7W8Mwdibn3uIecEAdOQDTSh5RjIFSUYs9b8FFYJXXrHPp/jCsf6jS7RmkGa1Iui1/JAIL8KEjtS7QmQ==</DQ><InverseQ>EDAJa3TpNdPQ3GIdBpnTgFTQY5A60DcszsUW/iCYoXQdPVJ9BLBxVTe9jiLzGuNuzLkVBwQlCy0Bf84hACRV9A==</InverseQ><D>cMFdDYKkddlRNczaugOmOH8b1egpx2liSPs6GYZ2gFObAXJiPK8m+r6c2ckls7hrlUP0DZhi4cG6Tn7xANb0Ek17P7QquVhQYOmFy/YHzm+IJbcwwq7pJHhZBhtcjyXqfUZ+BADGE//GQbrSVwVltpOj5KcxG88NAprLn2MMxfE=</D></RSAKeyValue>".to_string();

let pub_key = chilkat::PublicKey::new();
if pub_key.load_from_string(&pub_key_xml).is_err() {
    println!("{}", pub_key.last_error_text());
    return;
}

let priv_key = chilkat::PrivateKey::new();
if priv_key.load_xml(&priv_key_xml).is_err() {
    println!("{}", priv_key.last_error_text());
    return;
}

if rsa.use_public_key(&pub_key).is_err() {
    println!("{}", rsa.last_error_text());
    return;
}

// Encrypt a string and return the encrypted data base64-encoded:
rsa.set_encoding_mode("base64");

let plain_text = "RSA gives different results with each call, weird but OK".to_string();

let mut use_private_key = false;
let encrypted_str1 = rsa.encrypt_string_enc(&plain_text, use_private_key).unwrap_or_default();
println!("{}", encrypted_str1);

// Do it again. The results are different...
let encrypted_str2 = rsa.encrypt_string_enc(&plain_text, use_private_key).unwrap_or_default();
println!("{}", encrypted_str2);

// Now decrypt both strings, and the results are correct
// in both cases:
let rsa2 = chilkat::Rsa::new();
if rsa2.use_private_key(&priv_key).is_err() {
    println!("{}", rsa.last_error_text());
    return;
}

rsa2.set_encoding_mode("base64");
use_private_key = true;

let decrypted_str1 = rsa2.decrypt_string_enc(&encrypted_str1, use_private_key).unwrap_or_default();
println!("{}", decrypted_str1);

let decrypted_str2 = rsa2.decrypt_string_enc(&encrypted_str2, use_private_key).unwrap_or_default();
println!("{}", decrypted_str2);