Sample code for 30+ languages & platforms
C#

Duplicate PHP RSA Encryption

See more RSA Examples

Demonstrates how to duplicate the following PHP function.

Chilkat C# Downloads

C#
bool success = false;

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

//  Duplicate the following PHP code:
//  
//     public function encryptRSA($plainText,$rsaMOD,$pubKEY){
//          $rsa  = new RSA();
//          $rsa->setEncryptionMode(RSA::ENCRYPTION_PKCS1);
//          $publicKey = [
//              'e' => new BigInteger($pubKEY,16),
//              'n' => new BigInteger($rsaMOD,16)
//          ];
//  		
//          $rsa->loadKey($publicKey);
//          $ciphertext = $rsa->encrypt($plainText);
//          return bin2hex($ciphertext);
//      }
//  
//      $plainText="key=abcdefghijkmnopq&iv=abcdefghijkmnopq&h=12345678&s=12345678"
//      $rsaMOD="F0946D8F05604809E24B8CFFD30349CEA9E5F4D320BFD9E9AA1B088863F02C43E7997D37A3E27B4F8F359F1744DB6B20A437067C0D325A80660D12FF56A57673"
//      $pubKEY="010001"

//  We have the RSA modulus in hex
string rsaMOD = "F0946D8F05604809E24B8CFFD30349CEA9E5F4D320BFD9E9AA1B088863F02C43E7997D37A3E27B4F8F359F1744DB6B20A437067C0D325A80660D12FF56A57673";

//  The RSA exponent in hex is "010001", which is 65537 in decimal.  It's typically the exponent that is always used.
string rsaEXP = "010001";

//  Get the RSA modulus and exponent in base64.
Chilkat.BinData bdMod = new Chilkat.BinData();
Chilkat.BinData bdExp = new Chilkat.BinData();
success = bdMod.AppendEncoded(rsaMOD,"hex");
success = bdExp.AppendEncoded(rsaEXP,"hex");

//  Build the XML representation of the RSA public key
Chilkat.Xml xml = new Chilkat.Xml();
xml.Tag = "RSAPublicKey";
xml.UpdateChildContent("Modulus",bdMod.GetEncoded("base64"));
xml.UpdateChildContent("Exponent",bdExp.GetEncoded("base64"));

//  Load the RSA public key into a Chilkat public key object.
Chilkat.PublicKey pubkey = new Chilkat.PublicKey();
success = pubkey.LoadFromString(xml.GetXml());

//  Setup the RSA object for encryption and do it..
Chilkat.Rsa rsa = new Chilkat.Rsa();
rsa.VerboseLogging = true;
success = rsa.UsePublicKey(pubkey);

//  Use PKCSv1.5 padding
rsa.PkcsPadding = true;

//  Encrypt and return the string as hex.
rsa.EncodingMode = "hex";
string plainText = "key=abcdefghijkmnopq&iv=abcdefghijkmnopq&h=12345678&s=12345678";
string cipherText = rsa.EncryptStringENC(plainText,false);
if (rsa.LastMethodSuccess == false) {
    Debug.WriteLine(rsa.LastErrorText);
    return;
}

//  Note: The PKCSv1_5 padding incorporates random bytes.  Therefore, the RSA encryption will produce different results each time -- all of which are valid 
//  and decrypt correctly to the same original text.
Debug.WriteLine(cipherText);