Delphi DLL Requires Chilkat v11.0.0+

RSA Encrypt and Decrypt Credit Card Numbers

See more RSA Examples

_LANGUAGE_ sample code to RSA public-key encrypt and decrypt credit card numbers. The RSA key is loaded from an unencrypted PKCS8 file. Chilkat provides many ways of setting the key -- loading from both encrypted and unencrypted PEM, PKCS8, DER, PVK, etc. Keys may be loaded from files or in-memory representations. (The RSA component also provides the ability to generate RSA keys.) Delphi DLL

var
success: Boolean;
rsa: HCkRsa;
privKey: HCkPrivateKey;
pubKey: HCkPublicKey;
ccNumber: PWideChar;
usePrivateKey: Boolean;
encryptedStr: PWideChar;
rsaDecryptor: HCkRsa;
decryptedStr: PWideChar;

begin
success := False;

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

rsa := CkRsa_Create();

privKey := CkPrivateKey_Create();

//  Load an RSA private key from a file:
success := CkPrivateKey_LoadAnyFormatFile(privKey,'rsaPrivateKey.key','');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

//  Get the public part of the private key.
pubKey := CkPublicKey_Create();
CkPrivateKey_ToPublicKey(privKey,pubKey);

success := CkRsa_UsePublicKey(rsa,pubKey);
if (success = False) then
  begin
    Memo1.Lines.Add(CkRsa__lastErrorText(rsa));
    Exit;
  end;

//  Encrypt a VISA credit card number:
//  1234-5678-0000-9999
ccNumber := '1234567800009999';

usePrivateKey := False;
CkRsa_putEncodingMode(rsa,'base64');
encryptedStr := CkRsa__encryptStringENC(rsa,ccNumber,usePrivateKey);
Memo1.Lines.Add('Encrypted:');
Memo1.Lines.Add(encryptedStr);

//  Now decrypt:
rsaDecryptor := CkRsa_Create();

CkRsa_putEncodingMode(rsaDecryptor,'base64');
CkRsa_UsePrivateKey(rsaDecryptor,privKey);

usePrivateKey := True;
decryptedStr := CkRsa__decryptStringENC(rsaDecryptor,encryptedStr,usePrivateKey);

Memo1.Lines.Add('Decrypted:');
Memo1.Lines.Add(decryptedStr);

//  Important: RSA encryption should only be used to encrypt small amounts of data.
//  It is typically used for encrypting symmetric encryption
//  keys such that a symmetric encryption algorithm, such as 
//  AES is then used to encrypt/decrypt bulk data.

CkRsa_Dispose(rsa);
CkPrivateKey_Dispose(privKey);
CkPublicKey_Dispose(pubKey);
CkRsa_Dispose(rsaDecryptor);