(Delphi ActiveX) Create a Hash Signature for Value Added Tax Audit SOAP Message for Angola

Demonstrates how to create a hash signature that is required in Value Added Tax Audit Files in Angola, Africa.

It is the following two instructions that should be used to create a hash value to be put into a <hash></hash> field in SOAP XML file containing the tax data for the VAT authorities:

openssl dgst -shal -sign private.pem -outRegisto1.shal Registo1.txt

then

openssl enc -base64 - in Registo1.shal -out Registo1.b64 -A

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

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
pkey: TPrivateKey;
success: Integer;
rsa: TChilkatRsa;
b64sig: WideString;

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

pkey := TPrivateKey.Create(Self);

// Load the private key from an PEM file.
// Provide the password in the 2nd argument.
// If no password is needed, just pass an empty string.
success := pkey.LoadAnyFormatFile('qa_data/rsa/rsaPrivKey_secret.pem','secret');
if (success <> 1) then
  begin
    Memo1.Lines.Add(pkey.LastErrorText);
    Exit;
  end;

// Assuming this is an RSA private key..
rsa := TChilkatRsa.Create(Self);

// Import the private key into the RSA object:
success := rsa.ImportPrivateKeyObj(pkey.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

// OpenSSL uses big-endian.
rsa.LittleEndian := 0;

// SHA1 hash and sign, and return base64.
rsa.EncodingMode := 'base64';
b64sig := rsa.SignStringENC('2018-05-18,2018-05-18T11:22:19;FAC 001/18;53.00;','sha1');
Memo1.Lines.Add(b64sig);

// The signature is equal in size to your private key.  For example, if you have a 1024-bit RSA key,
// then 1024 bits = 128 bytes.   When 128 bytes is base64 encoded, the result is a string approximately
// 4/3rds the size of the original.  128 * 4 / 3 = (approximately) 172 bytes.

// If your RSA key is 2048-bits, then your signature will be twice as long.
end;