Delphi ActiveX

RSA Signature using Private Key from .snk File

See more RSA Examples

A .snk file (Strong Name Key file) is a file format used in the .NET ecosystem to store an RSA public/private key pair. This key pair is typically used for strong-naming assemblies, which is a process of signing .NET assemblies to ensure their integrity and to uniquely identify them.

This example loads a private key from a .snk file and creates an RSA signature.

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;
rsa: TChilkatRsa;
xmlStr: WideString;
privKey: TPrivateKey;
sigBase64: WideString;

begin
success := 0;

rsa := TChilkatRsa.Create(Self);

// Load the .snk and return the private key as XML.
xmlStr := rsa.SnkToXml('./test.snk');
if (rsa.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

privKey := TPrivateKey.Create(Self);
success := privKey.LoadXml(xmlStr);
if (success = 0) then
  begin
    Memo1.Lines.Add(privKey.LastErrorText);
    Exit;
  end;

success := rsa.UsePrivateKey(privKey.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

// Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
// Return the signature in base64 format.
rsa.EncodingMode := 'base64';
rsa.Charset := 'utf-8';
sigBase64 := rsa.SignStringENC('This is the text to be hashed and signed.','sha256');
if (rsa.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add('RSA signature as base64: ' + sigBase64);
end;