(Delphi ActiveX) Validate PDF Signatures

See more PDF Signatures Examples

This example demonstrates how to validate the signatures in a PDF and also shows how to get information from each signature.

Note: This example requires Chilkat v9.5.0.85 or greater.

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
pdf: TChilkatPdf;
success: Integer;
sigInfo: TChilkatJsonObject;
numSignatures: Integer;
validated: Integer;
i: Integer;
json: TChilkatJsonObject;
unauthAttrTimestampTokenTstInfoGenTime: TDtObj;
signingTime: TDtObj;
authAttrSigningTimeUtctime: TDtObj;
intVal: Integer;
strVal: WideString;
issuerCN: WideString;
serial: WideString;
certSerialNumber: WideString;
certIssuerCN: WideString;
certDigestAlgOid: WideString;
certDigestAlgName: WideString;
contentType: WideString;
messageDigest: WideString;
signingAlgOid: WideString;
signingAlgName: WideString;
authAttr1_2_840_113583_1_1_8Der: WideString;
authAttrContentTypeName: WideString;
authAttrContentTypeOid: WideString;
authAttrMessageDigestName: WideString;
authAttrMessageDigestDigest: WideString;
unauthAttrTimestampTokenName: WideString;
unauthAttrTimestampTokenDer: WideString;
unauthAttrTimestampTokenTimestampSignatureVerified: Integer;
unauthAttrTimestampTokenTstInfoTsaPolicyId: WideString;
unauthAttrTimestampTokenTstInfoMessageImprintHashAlg: WideString;
unauthAttrTimestampTokenTstInfoMessageImprintDigest: WideString;
unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches: Integer;
unauthAttrTimestampTokenTstInfoSerialNumber: WideString;
j: Integer;
count_j: Integer;
authAttrSigningTimeName: WideString;
authAttrSigningCertificateName: WideString;
authAttrSigningCertificateDer: WideString;
signatureDictionary_Contents: WideString;
signatureDictionary_Filter: WideString;
signatureDictionary_M: WideString;
signatureDictionary_Name: WideString;
signatureDictionary_Prop_Build_App_Name: WideString;
signatureDictionary_Prop_Build_App_R: Integer;
signatureDictionary_Prop_Build_App_REx: WideString;
signatureDictionary_Prop_Build_App_TrustedMode: Integer;
signatureDictionary_Prop_Build_Filter_Date: WideString;
signatureDictionary_Prop_Build_Filter_Name: WideString;
signatureDictionary_Prop_Build_Filter_R: Integer;
signatureDictionary_Prop_Build_Filter_V: Integer;
signatureDictionary_Prop_Build_PubSec_Date: WideString;
signatureDictionary_Prop_Build_PubSec_NonEFontNoWarn: Integer;
signatureDictionary_Prop_Build_PubSec_R: Integer;
signatureDictionary_SubFilter: WideString;
signatureDictionary_Type: WideString;
count_i: Integer;

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

pdf := TChilkatPdf.Create(Self);

// Load a PDF that has cryptographic signatures to be validated
success := pdf.LoadFile('qa_data/pdf/sign_testing_1/helloSigned2.pdf');
if (success = 0) then
  begin
    Memo1.Lines.Add(pdf.LastErrorText);
    Exit;
  end;

// Each time we verify a signature, information about the signature is written into
// sigInfo (replacing whatever sigInfo previously contained).
sigInfo := TChilkatJsonObject.Create(Self);
sigInfo.EmitCompact := 0;

// Iterate over each signature and validate each.
numSignatures := pdf.NumSignatures;
validated := 0;
i := 0;
while i < numSignatures do
  begin
    validated := pdf.VerifySignature(i,sigInfo.ControlInterface);
    Memo1.Lines.Add('Signature ' + IntToStr(i) + ' validated: ' + IntToStr(Ord(validated)));
    Memo1.Lines.Add(sigInfo.Emit());
    i := i + 1;
  end;

Memo1.Lines.Add('Finished.');

// When VerifySignature validates a signature, a lot of information is deposited into the JSON sigInfo object.
// The information can vary depending on what was included in the signature (for example, various authenticated attributes
// and unauthenticated attributes may or may not be included).
// Here is a sample of the information you'll see.
// 
// The following online tool can be used to generate code to parse any given JSON.
// Generate Parsing Code from JSON

// {
//   "validated": true,
//   "signatureDictionary": {         <--- This is the contents of the PDF Signature Dictionary for this signature.
//     "/ByteRange": [
//       0,
//       154682,
//       170512,
//       3233
//     ],
//     "/Contents": "<hex_data>",
//     "/Filter": "/Adobe.PPKLite",        <--- The meaning of the Signature Dictionary entries are defined in the PDF format specification document.
//     "/M": "D:20201006110216-05'00'",
//     "/Name": "yubikey rsa 1024 authentication",
//     "/Prop_Build": {
//       "/App": {
//         "/Name": "/Adobe#20Acrobat#20Pro#20DC",
//         "/OS": [
//           "/Win"
//         ],
//         "/R": 1313792,
//         "/REx": "2020.012.20048",
//         "/TrustedMode": true
//       },
//       "/Filter": {
//         "/Date": "Sep 11 2020 16:30:54",
//         "/Name": "/Adobe.PPKLite",
//         "/R": 131104,
//         "/V": 2
//       },
//       "/PubSec": {
//         "/Date": "Sep 11 2020 16:30:54",
//         "/NonEFontNoWarn": true,
//         "/R": 131105
//       }
//     },
//     "/SubFilter": "/adbe.pkcs7.detached",
//     "/Type": "/Sig"
//   },
//   "pkcs7": {          <--- This is the content of the CMS signature.
//     "verify": {
//       "certs": [      <--- Each signing certificate is listed here (by issuer common name and signing cert's serail number (in hex))
//         {
//           "issuerCN": "yubikey rsa 1024 authentication",
//           "serial": "66BE58138D761E92BC594A722932657BE26D421F"
//         }
//       ],
//       "digestAlgorithms": [
//         "sha256"
//       ],
//       "signerInfo": [     <--- contains data from each SignerInfo
//         {
//           "cert": {
//             "serialNumber": "66BE58138D761E92BC594A722932657BE26D421F",
//             "issuerCN": "yubikey rsa 1024 authentication",
//             "digestAlgOid": "2.16.840.1.101.3.4.2.1",
//             "digestAlgName": "SHA256"
//           },
//           "contentType": "1.2.840.113549.1.7.1",
//           "messageDigest": "btQOuSEvC31mdRFHtyEUPw8R9NuKfk0XPcQ6Lcmn6pk=",
//           "signingAlgOid": "1.2.840.113549.1.1.11",
//           "signingAlgName": "RSA-SHA256-PKCSV-1_5",
//           "authAttr": {     <--- CMS authenticated attributes are contained here.
//             "1.2.840.113583.1.1.8": {
//               "der": "MAA="
//             },
//             "1.2.840.113549.1.9.3": {
//               "name": "contentType",
//               "oid": "1.2.840.113549.1.7.1"
//             },
//             "1.2.840.113549.1.9.4": {
//               "name": "messageDigest",
//               "digest": "btQOuSEvC31mdRFHtyEUPw8R9NuKfk0XPcQ6Lcmn6pk="
//             }
//           },
//           "unauthAttr": {    <--- CMS unauthenticated attributes are contained here.
//             "1.2.840.113549.1.9.16.2.14": {
//               "name": "timestampToken",
//               "der": "MIIOvAYJKo ... Es/70g=",
//               "verify": {
//                 "digestAlgorithms": [
//                   "sha256"
//                 ],
//                 "signerInfo": [
//                   {
//                     "cert": {
//                       "serialNumber": "04CD3F8568AE76C61BB0FE7160CCA76D",
//                       "issuerCN": "DigiCert SHA2 Assured ID Timestamping CA",
//                       "digestAlgOid": "2.16.840.1.101.3.4.2.1",
//                       "digestAlgName": "SHA256"
//                     },
//                     "contentType": "1.2.840.113549.1.9.16.1.4",
//                     "signingTime": "201006160423Z",
//                     "messageDigest": "Atv5Rj3kidB8IR6CplYiX3o6De/k8SC6JJ6uUPAGO0g=",
//                     "signingAlgOid": "1.2.840.113549.1.1.1",
//                     "signingAlgName": "RSA-PKCSV-1_5",
//                     "authAttr": {
//                       "1.2.840.113549.1.9.3": {
//                         "name": "contentType",
//                         "oid": "1.2.840.113549.1.9.16.1.4"
//                       },
//                       "1.2.840.113549.1.9.5": {
//                         "name": "signingTime",
//                         "utctime": "201006160423Z"
//                       },
//                       "1.2.840.113549.1.9.16.2.12": {
//                         "name": "signingCertificate",
//                         "der": "MBowGDAWBBQDJb1QXtqWMC3CL0+gHkwovig0xQ=="
//                       },
//                       "1.2.840.113549.1.9.4": {
//                         "name": "messageDigest",
//                         "digest": "Atv5Rj3kidB8IR6CplYiX3o6De/k8SC6JJ6uUPAGO0g="
//                       }
//                     }
//                   }
//                 ]
//               },
//               "timestampSignatureVerified": true,
//               "tstInfo": {
//                 "tsaPolicyId": "2.16.840.1.114412.7.1",
//                 "messageImprint": {
//                   "hashAlg": "sha256",
//                   "digest": "gLJtrRWUSDfjzDkF1MfWG1wyHA6FrUJLkWMGRG+eMlA=",
//                   "digestMatches": true
//                 },
//                 "serialNumber": "00CE57E1113970607EF63B1D1160545321",
//                 "genTime": "20201006160423Z"
//               }
//             }
//           }
//         }
//       ],
//       "pkcs7": {
//         "verify": {
//           "certs": [
//             {
//               "issuerCN": "DigiCert SHA2 Assured ID Timestamping CA",
//               "serial": "04CD3F8568AE76C61BB0FE7160CCA76D"
//             },
//             {
//               "issuerCN": "DigiCert Assured ID Root CA",
//               "serial": "0AA125D6D6321B7E41E405DA3697C215"
//             }
//           ]
//         }
//       }
//     }
//   }
// }

// **** The point of this code is to show how to get at each desired piece of information contained in the signature.
// **** If your signature contains additional information not shown here, then you can use the online tool to generate the parse code.
// **** It is likely you're only interested in a few items of information, and therefore you wouldn't copy all of this code, but might
// **** choose to use bits and pieces to get the information you find important.

json := TChilkatJsonObject.Create(Self);

// Imagine that the "json" object contains the information obtained by validating a signature...
// The code below was generated using the online tool:  Generate Parsing Code from JSON

unauthAttrTimestampTokenTstInfoGenTime := TDtObj.Create(Self);
signingTime := TDtObj.Create(Self);
authAttrSigningTimeUtctime := TDtObj.Create(Self);

validated := json.BoolOf('validated');
signatureDictionary_Contents := json.StringOf('signatureDictionary./Contents');
signatureDictionary_Filter := json.StringOf('signatureDictionary./Filter');
signatureDictionary_M := json.StringOf('signatureDictionary./M');
signatureDictionary_Name := json.StringOf('signatureDictionary./Name');
signatureDictionary_Prop_Build_App_Name := json.StringOf('signatureDictionary./Prop_Build./App./Name');
signatureDictionary_Prop_Build_App_R := json.IntOf('signatureDictionary./Prop_Build./App./R');
signatureDictionary_Prop_Build_App_REx := json.StringOf('signatureDictionary./Prop_Build./App./REx');
signatureDictionary_Prop_Build_App_TrustedMode := json.BoolOf('signatureDictionary./Prop_Build./App./TrustedMode');
signatureDictionary_Prop_Build_Filter_Date := json.StringOf('signatureDictionary./Prop_Build./Filter./Date');
signatureDictionary_Prop_Build_Filter_Name := json.StringOf('signatureDictionary./Prop_Build./Filter./Name');
signatureDictionary_Prop_Build_Filter_R := json.IntOf('signatureDictionary./Prop_Build./Filter./R');
signatureDictionary_Prop_Build_Filter_V := json.IntOf('signatureDictionary./Prop_Build./Filter./V');
signatureDictionary_Prop_Build_PubSec_Date := json.StringOf('signatureDictionary./Prop_Build./PubSec./Date');
signatureDictionary_Prop_Build_PubSec_NonEFontNoWarn := json.BoolOf('signatureDictionary./Prop_Build./PubSec./NonEFontNoWarn');
signatureDictionary_Prop_Build_PubSec_R := json.IntOf('signatureDictionary./Prop_Build./PubSec./R');
signatureDictionary_SubFilter := json.StringOf('signatureDictionary./SubFilter');
signatureDictionary_Type := json.StringOf('signatureDictionary./Type');
i := 0;
count_i := json.SizeOfArray('signatureDictionary./ByteRange');
while i < count_i do
  begin
    json.I := i;
    intVal := json.IntOf('signatureDictionary./ByteRange[i]');
    i := i + 1;
  end;

i := 0;
count_i := json.SizeOfArray('signatureDictionary./Prop_Build./App./OS');
while i < count_i do
  begin
    json.I := i;
    strVal := json.StringOf('signatureDictionary./Prop_Build./App./OS[i]');
    i := i + 1;
  end;

i := 0;
count_i := json.SizeOfArray('pkcs7.verify.certs');
while i < count_i do
  begin
    json.I := i;
    issuerCN := json.StringOf('pkcs7.verify.certs[i].issuerCN');
    serial := json.StringOf('pkcs7.verify.certs[i].serial');
    i := i + 1;
  end;

i := 0;
count_i := json.SizeOfArray('pkcs7.verify.digestAlgorithms');
while i < count_i do
  begin
    json.I := i;
    strVal := json.StringOf('pkcs7.verify.digestAlgorithms[i]');
    i := i + 1;
  end;

i := 0;
count_i := json.SizeOfArray('pkcs7.verify.signerInfo');
while i < count_i do
  begin
    json.I := i;
    certSerialNumber := json.StringOf('pkcs7.verify.signerInfo[i].cert.serialNumber');
    certIssuerCN := json.StringOf('pkcs7.verify.signerInfo[i].cert.issuerCN');
    certDigestAlgOid := json.StringOf('pkcs7.verify.signerInfo[i].cert.digestAlgOid');
    certDigestAlgName := json.StringOf('pkcs7.verify.signerInfo[i].cert.digestAlgName');
    contentType := json.StringOf('pkcs7.verify.signerInfo[i].contentType');
    messageDigest := json.StringOf('pkcs7.verify.signerInfo[i].messageDigest');
    signingAlgOid := json.StringOf('pkcs7.verify.signerInfo[i].signingAlgOid');
    signingAlgName := json.StringOf('pkcs7.verify.signerInfo[i].signingAlgName');
    authAttr1_2_840_113583_1_1_8Der := json.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113583.1.1.8".der');
    authAttrContentTypeName := json.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".name');
    authAttrContentTypeOid := json.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".oid');
    authAttrMessageDigestName := json.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".name');
    authAttrMessageDigestDigest := json.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".digest');
    unauthAttrTimestampTokenName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".name');
    unauthAttrTimestampTokenDer := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".der');
    unauthAttrTimestampTokenTimestampSignatureVerified := json.BoolOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".timestampSignatureVerified');
    unauthAttrTimestampTokenTstInfoTsaPolicyId := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.tsaPolicyId');
    unauthAttrTimestampTokenTstInfoMessageImprintHashAlg := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.messageImprint.hashAlg');
    unauthAttrTimestampTokenTstInfoMessageImprintDigest := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.messageImprint.digest');
    unauthAttrTimestampTokenTstInfoMessageImprintDigestMatches := json.BoolOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.messageImprint.digestMatches');
    unauthAttrTimestampTokenTstInfoSerialNumber := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.serialNumber');
    json.DtOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".tstInfo.genTime',0,unauthAttrTimestampTokenTstInfoGenTime.ControlInterface);
    j := 0;
    count_j := json.SizeOfArray('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.digestAlgorithms');
    while j < count_j do
      begin
        json.J := j;
        strVal := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.digestAlgorithms[j]');
        j := j + 1;
      end;

    j := 0;
    count_j := json.SizeOfArray('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo');
    while j < count_j do
      begin
        json.J := j;
        certSerialNumber := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.serialNumber');
        certIssuerCN := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.issuerCN');
        certDigestAlgOid := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.digestAlgOid');
        certDigestAlgName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].cert.digestAlgName');
        contentType := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].contentType');
        json.DtOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].signingTime',0,signingTime.ControlInterface);
        messageDigest := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].messageDigest');
        signingAlgOid := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].signingAlgOid');
        signingAlgName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].signingAlgName');
        authAttrContentTypeName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.3".name');
        authAttrContentTypeOid := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.3".oid');
        authAttrSigningTimeName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.5".name');
        json.DtOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.5".utctime',0,authAttrSigningTimeUtctime.ControlInterface);
        authAttrSigningCertificateName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.16.2.12".name');
        authAttrSigningCertificateDer := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.16.2.12".der');
        authAttrMessageDigestName := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.4".name');
        authAttrMessageDigestDigest := json.StringOf('pkcs7.verify.signerInfo[i].unauthAttr."1.2.840.113549.1.9.16.2.14".verify.signerInfo[j].authAttr."1.2.840.113549.1.9.4".digest');
        j := j + 1;
      end;

    i := i + 1;
  end;

i := 0;
count_i := json.SizeOfArray('pkcs7.verify.pkcs7.verify.certs');
while i < count_i do
  begin
    json.I := i;
    issuerCN := json.StringOf('pkcs7.verify.pkcs7.verify.certs[i].issuerCN');
    serial := json.StringOf('pkcs7.verify.pkcs7.verify.certs[i].serial');
    i := i + 1;
  end;
end;