C#

RSA Encrypt/Decrypt Bytes

See more RSA Examples

Demonstrates how to RSA encrypt and decrypt byte data. C#

bool success = false;

//  The RSA public key is used for encryption, and the private key for decryption.

//  The public key's role is to make encryption accessible to anyone while ensuring that
//  only the private key holder can decrypt the messages.
//  The public key is designed to be widely distributed so anyone can use it to encrypt messages
//  intended for the owner of the private key.

//  Load our 2048-bit RSA public key.
Chilkat.PublicKey pubKey = new Chilkat.PublicKey();
//  In all Chilkat methods expecting a path, you pass either absolute or relative paths.
success = pubKey.LoadFromFile("qa_data/rsaKeys/myTestRsaPublic.pem");
if (success == false) {
    Debug.WriteLine(pubKey.LastErrorText);
    return;
}

Chilkat.Rsa rsa = new Chilkat.Rsa();

//  Tell RSA to use the public key.
rsa.UsePublicKey(pubKey);

//  RSA encryption is for small amounts of data, on the order of 200 bytes or less.
//  The maximum number of bytes that can be RSA encrypted depends
//  on the RSA key size and padding scheme (OAEP padding vs PKCS#1 v1.5 padding).
//  For specific limits, see: RSA Encryption Maximum Number of Bytes

//  A typical use for RSA is to encrypt symmetric encryption keys, such as an AES key.
Chilkat.Prng prng = new Chilkat.Prng();
byte[] keyBytes = null;
keyBytes = prng.GenRandomBytes(32);

byte[] encBytes = null;
encBytes = rsa.EncryptBytes(keyBytes,false);

//  ------------------------------------------------------------------------------------------------------------------------
//  Let's decrypt, which requires the matching private key...

//  Load the matching 2048-bit RSA private key.
Chilkat.PrivateKey privKey = new Chilkat.PrivateKey();
string password = "secret";
success = privKey.LoadAnyFormatFile("qa_data/rsaKeys/myTestRsaPrivate.pem",password);
if (success == false) {
    Debug.WriteLine(privKey.LastErrorText);
    return;
}

//  Tell the RSA object to use the private key.
rsa.UsePrivateKey(privKey);

byte[] decBytes = null;
decBytes = rsa.DecryptBytes(encBytes,true);
if (success == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

Debug.WriteLine("Success.");