Delphi ActiveX Requires Chilkat v11.0.0+

Duplicate openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

See more OpenSSL Examples

Demonstrates how to duplicate this OpenSSL command:

openssl dgst -sha256 -verify pubKey.pem -signature signature.sig in.dat

The in.dat file contains the original data that was signed, and can contain text or binary data of any type. The above OpenSSL command does the following:

1. Creates a SHA256 digest of the contents of the input file.
2. Verifies the SHA256 digest using the public key.

Delphi ActiveX

var
success: Integer;
pubKey: TPublicKey;
bdFileData: TChilkatBinData;
bdSig: TChilkatBinData;
rsa: TChilkatRsa;

begin
success := 0;

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

pubKey := TPublicKey.Create(Self);

//  Load the public key from an PEM file:
success := pubKey.LoadFromFile('pubKey.pem');
if (success = 0) then
  begin
    Memo1.Lines.Add(pubKey.LastErrorText);
    Exit;
  end;

//  Load the data of the original file that was signed.
bdFileData := TChilkatBinData.Create(Self);
success := bdFileData.LoadFile('in.dat');

//  Load the signature.
bdSig := TChilkatBinData.Create(Self);
success := bdSig.LoadFile('signature.sig');

rsa := TChilkatRsa.Create(Self);

//  Import the public key into the RSA component:
success := rsa.UsePublicKey(pubKey.ControlInterface);
if (success = 0) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Exit;
  end;

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

success := rsa.VerifyBd(bdFileData.ControlInterface,'sha256',bdSig.ControlInterface);
if (success <> 1) then
  begin
    Memo1.Lines.Add(rsa.LastErrorText);
    Memo1.Lines.Add('The signature was invalid.');
    Exit;
  end;

Memo1.Lines.Add('The signature was verified.');