C#

RSA Encrypt Bytes to Base64 and Reverse

See more RSA Examples

Demonstrates how to RSA encrypt bytes to base64 and the reverse. 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);

rsa.EncodingMode = "base64";
string encryptedB64 = rsa.EncryptBytesENC(keyBytes,false);

Debug.WriteLine("Result:");
Debug.WriteLine(encryptedB64);

//  Sample output:
//  hTTV4Lbmm2V7NCw/HaoJL8Aq/MM/HXblQnjitrF9HY1zBlISwui2jGVVZDtZcZ/rICOpPw44w8Qb8AswFVE1sryydmNEvcIfYAp/xgdBPXBERAS0y4AoEzUfuC5TJmJFvnFkl2lX8GAclANfcTik38V+k3EXu5wPzHKNFb07c6jnwh3Jm4f3PRUhmmB2NO5kSWqHsx0dNglOTq5BUZx34nxlXL5G8d7mXqITsUtrOHXAO/Gb7IrvB81Xk2vc5p4yHhiY/rFTHTTmZyzte2qHGm7V6xPRNURjiivnMY2jQU0Um1JKQcAiSe8Suwvd2LXP5PIhl71VLgO+fokjnynfRg==

//  ------------------------------------------------------------------------------------------------------------------------
//  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.DecryptBytesENC(encryptedB64,true);
if (success == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

Debug.WriteLine("Success.");