(Delphi ActiveX) Validate a .pkpass Archive

Opens a .pkpass archive (which is just a .zip renamed to .pkpass) and validates the contents. The hashes in the manifest are compared with the computed hash values for each individual file. If all computed hash values match, then the signature is verified.

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
crypt: TChilkatCrypt2;
zip: TChilkatZip;
success: Integer;
ent: IChilkatZipEntry;
bdManifest: TChilkatBinData;
json: TChilkatJsonObject;
someHashesFailed: Integer;
filename: WideString;
sbHashHex: TChilkatStringBuilder;
bdFileData: TChilkatBinData;
numMembers: Integer;
i: Integer;
computedHashHex: WideString;
bdSignature: TChilkatBinData;
verified: Integer;

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

crypt := TChilkatCrypt2.Create(Self);
zip := TChilkatZip.Create(Self);

success := zip.OpenZip('qa_data/pkpass/invalid.pkpass');
if (success = 0) then
  begin
    Memo1.Lines.Add(zip.LastErrorText);
    Exit;
  end;

// Get the contents of the manifest.json file, which contains something like this:

// {
//   "icon.png" : "0296b01347b3173e98438a003b0e88986340b2d8",
//   "logo.png" : "25de09e2d3b01ce1fe00c2ca9a90a2be1aaa05cf",
//   "icon@2x.png" : "5afd9585b08c65fdf105a90c8bd643407cba2787",
//   "pass.json" : "145ea5a5db784fff485126c77ecf7a1fc2a88ee7",
//   "strip@2x.png" : "468fa7bc93e6b55342b56fda09bdce7c829d7d46",
//   "strip.png" : "736d01f84cb73d06e8a9932e43076d68f19461ff"
// }

ent := zip.GetEntryByName('manifest.json');
if (zip.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add('manifest.json entry not found.');
    Exit;
  end;

// Get the exact content of the manifest.json for later signature verification.
bdManifest := TChilkatBinData.Create(Self);
success := ent.UnzipToBd(bdManifest.ControlInterface);

json := TChilkatJsonObject.Create(Self);
json.EmitCompact := 0;
json.Load(ent.UnzipToString(0,'utf-8'));
Memo1.Lines.Add(json.Emit());

// For each file in the JSON, get the filename and hex hash value.
crypt.EncodingMode := 'hexlower';
crypt.HashAlgorithm := 'sha1';

someHashesFailed := 0;

sbHashHex := TChilkatStringBuilder.Create(Self);
bdFileData := TChilkatBinData.Create(Self);
numMembers := json.Size;
i := 0;
while i < numMembers do
  begin
    filename := json.NameAt(i);
    sbHashHex.Clear();
    sbHashHex.Append(json.StringAt(i));

    ent := zip.GetEntryByName(filename);
    if (zip.LastMethodSuccess = 0) then
      begin
        Memo1.Lines.Add(filename + ' not found in the pkpass file.');
        Exit;
      end;

    // Get the data for this file.
    bdFileData.Clear();
    success := ent.UnzipToBd(bdFileData.ControlInterface);

    computedHashHex := crypt.HashBdENC(bdFileData.ControlInterface);
    if (sbHashHex.ContentsEqual(computedHashHex,0) = 0) then
      begin
        Memo1.Lines.Add('Computed hash does not match stored hash for ' + filename);
        Memo1.Lines.Add('  computed: ' + computedHashHex);
        Memo1.Lines.Add('  stored:   ' + sbHashHex.GetAsString());
        someHashesFailed := 1;
      end
    else
      begin
        Memo1.Lines.Add('hash verified for ' + filename + '(' + computedHashHex + ')');
      end;

    i := i + 1;
  end;

if (someHashesFailed = 1) then
  begin
    Memo1.Lines.Add('Some hashes failed.');
    Exit;
  end;

// Let's verify the signature..
// First get the signature.
ent := zip.GetEntryByName('signature');
if (zip.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add('signature not found in the pkpass file.');
    Exit;
  end;

bdSignature := TChilkatBinData.Create(Self);
success := ent.UnzipToBd(bdSignature.ControlInterface);

// Show the contents of the signature in base64 encoding.
Memo1.Lines.Add('Signature:');
Memo1.Lines.Add(bdSignature.GetEncoded('base64_mime'));
Memo1.Lines.Add('----');

// Verify the signature against the manifest.json
crypt.EncodingMode := 'base64';
verified := crypt.VerifyBdENC(bdManifest.ControlInterface,bdSignature.GetEncoded('base64'));
if (verified = 0) then
  begin
    Memo1.Lines.Add(crypt.LastErrorText);
  end;
Memo1.Lines.Add('signature verified = ' + IntToStr(Ord(verified)));
end;