Delphi DLL Requires Chilkat v11.0.0+

RSA Encrypt and Decrypt Strings

See more RSA Examples

_LANGUAGE_ sample code to RSA public-key encrypt and decrypt strings using public and private keys. Delphi DLL

var
success: Boolean;
rsa: HCkRsa;
privKey: HCkPrivateKey;
pubKey: HCkPublicKey;
plainText: PWideChar;
rsaEncryptor: HCkRsa;
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();

//  This example also generates the public and private
//  keys to be used in the RSA encryption.
//  Normally, you would generate a key pair once,
//  and distribute the public key to your partner.
//  Anything encrypted with the public key can be
//  decrypted with the private key.  The reverse is 
//  also true: anything encrypted using the private
//  key can be decrypted using the public key.

//  Generate a 2048-bit key.  Chilkat RSA supports
//  key sizes ranging from 512 bits to 4096 bits.
privKey := CkPrivateKey_Create();
success := CkRsa_GenKey(rsa,2048,privKey);
if (success = False) then
  begin
    Memo1.Lines.Add(CkRsa__lastErrorText(rsa));
    Exit;
  end;

pubKey := CkPublicKey_Create();
CkPrivateKey_ToPublicKey(privKey,pubKey);

plainText := 'Encrypting and decrypting should be easy!';

//  Start with a new RSA object to demonstrate that all we
//  need are the keys previously exported:
rsaEncryptor := CkRsa_Create();

//  Encrypted output is always binary.  In this case, we want
//  to encode the encrypted bytes in a printable string.
//  Our choices are "hex", "base64", "url", "quoted-printable".
CkRsa_putEncodingMode(rsaEncryptor,'hex');

//  We'll encrypt with the public key and decrypt with the private
//  key.
success := CkRsa_UsePublicKey(rsaEncryptor,pubKey);

usePrivateKey := False;
encryptedStr := CkRsa__encryptStringENC(rsaEncryptor,plainText,usePrivateKey);
Memo1.Lines.Add(encryptedStr);

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

CkRsa_putEncodingMode(rsaDecryptor,'hex');
success := CkRsa_UsePrivateKey(rsaDecryptor,privKey);

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

Memo1.Lines.Add(decryptedStr);

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