Delphi ActiveX

CMS Sign Hash

Demonstrates how to use the SignHashENC method to sign a pre-computed hash. This method creates a CMS signature (PKCS7 detached signature).

This example requires Chilkat v9.5.0.90 or later.

Delphi ActiveX

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Chilkat_TLB;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Integer;
crypt: TChilkatCrypt2;
base64Hash: WideString;
cert: TChilkatCert;
base64CmsSig: WideString;

begin
success := 0;

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

crypt := TChilkatCrypt2.Create(Self);

// Create the hash to be signed...
crypt.HashAlgorithm := 'sha256';
crypt.EncodingMode := 'base64';
crypt.Charset := 'utf-8';
// Create the SHA256 hash of a string using the utf-8 byte representation.
// Return the hash as base64.
base64Hash := crypt.HashStringENC('This is the string to be hashed');

// Load a certificate for signing.
cert := TChilkatCert.Create(Self);
success := cert.LoadPfxFile('qa_data/pfx/cert_test123.pfx','test123');
if (success = 0) then
  begin
    Memo1.Lines.Add(cert.LastErrorText);
    Exit;
  end;
crypt.SetSigningCert(cert.ControlInterface);

// Sign the hash to create a base64 CMS signature (which does not contain the original data).
// We can get the signature in a single line of base64 by specifying "base64", or 
// we can get multi-line base64 by specifying "base64_mime".
crypt.EncodingMode := 'base64_mime';
base64CmsSig := crypt.SignHashENC(base64Hash,'sha256','base64');
if (crypt.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
    Exit;
  end;

// Note: In the above call to SignHashENC, the encoding of the returned CMS signature is specified by the EncodingMode property.
// However, the encoding of the passed-in hash is indicated by the 3rd argument.

Memo1.Lines.Add('CMS Signature: ' + base64CmsSig);
end;