Delphi DLL

RSA Hash Binary Data and Sign (and Verify)

See more RSA Examples

Demonstrates how to sign the hash of binary data. Also demonstrates how to verify the RSA signature. Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, BinData, PrivateKey, Rsa, PublicKey;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
privKey: HCkPrivateKey;
rsa: HCkRsa;
originalData: PWideChar;
bdData: HCkBinData;
bdSignature: HCkBinData;
pubKey: HCkPublicKey;
rsa2: HCkRsa;
bVerified: Boolean;

begin
success := False;

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

// Load an RSA private key for signing.
privKey := CkPrivateKey_Create();
success := CkPrivateKey_LoadEncryptedPemFile(privKey,'qa_data/pem/rsa_passwd.pem','passwd');
if (success = False) then
  begin
    Memo1.Lines.Add(CkPrivateKey__lastErrorText(privKey));
    Exit;
  end;

rsa := CkRsa_Create();
CkRsa_UsePrivateKey(rsa,privKey);

// We have some binary data (in hex) to sign
originalData := '0102030405060708090A';
bdData := CkBinData_Create();
CkBinData_AppendEncoded(bdData,originalData,'hex');

// Hash (SHA-256) and sign the hash:
bdSignature := CkBinData_Create();
success := CkRsa_SignBd(rsa,bdData,'sha256',bdSignature);
if (success = False) then
  begin
    Memo1.Lines.Add(CkRsa__lastErrorText(rsa));
    Exit;
  end;

// Show the RSA signature in base64
Memo1.Lines.Add(CkBinData__getEncoded(bdSignature,'base64'));

// ------------------------------------------
// Get the public key from the private key
pubKey := CkPublicKey_Create();
CkPrivateKey_ToPublicKey(privKey,pubKey);

// Verify the signature..
rsa2 := CkRsa_Create();
CkRsa_UsePublicKey(rsa2,pubKey);

bVerified := CkRsa_VerifyBd(rsa2,bdData,'sha256',bdSignature);
Memo1.Lines.Add('signature verified: ' + IntToStr(Ord(bVerified)));

CkPrivateKey_Dispose(privKey);
CkRsa_Dispose(rsa);
CkBinData_Dispose(bdData);
CkBinData_Dispose(bdSignature);
CkPublicKey_Dispose(pubKey);
CkRsa_Dispose(rsa2);

end;