(Delphi DLL) Verify and Unwrap S/MIME, and get Information about CMS Signature

Demonstrates calling the Verify method to verify and unwrap S/MIME. The MIME is restored to the original structure that it would have originally had prior to signing. The Verify method works with both detached signatures, as well as opaque/attached signatures.

Calls LastJsonData to get information about the signature(s) that were verified.

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Mime, DtObj, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
mime: HCkMime;
success: Boolean;
verified: Boolean;
json: HCkJsonObject;
signingTime: HCkDtObj;
authAttrSigningTimeUtctime: HCkDtObj;
issuerCN: PWideChar;
serial: PWideChar;
strVal: PWideChar;
certSerialNumber: PWideChar;
certIssuerCN: PWideChar;
certDigestAlgOid: PWideChar;
certDigestAlgName: PWideChar;
contentType: PWideChar;
messageDigest: PWideChar;
signingAlgOid: PWideChar;
signingAlgName: PWideChar;
authAttrContentTypeName: PWideChar;
authAttrContentTypeOid: PWideChar;
authAttrSigningTimeName: PWideChar;
authAttrMessageDigestName: PWideChar;
authAttrMessageDigestDigest: PWideChar;
authAttr1_2_840_113549_1_9_15Der: PWideChar;
authAttr1_3_6_1_4_1_311_16_4Der: PWideChar;
i: Integer;
count_i: Integer;

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

mime := CkMime_Create();

// Load the signed MIME from a file...
success := CkMime_LoadMimeFile(mime,'qa_data/mime/detached_sig.eml');
if (success = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

// Verify the S/MIME and restore the MIME
// to the structure/content it had prior to signing.
verified := CkMime_Verify(mime);
if (verified = False) then
  begin
    Memo1.Lines.Add(CkMime__lastErrorText(mime));
    Exit;
  end;

// Examine the details of what was verified.
json := CkMime_LastJsonData(mime);
CkJsonObject_putEmitCompact(json,False);
Memo1.Lines.Add(CkJsonObject__emit(json));

// The code to parse the following JSON (i.e. extract desired information) is shown below..

// {
//   "pkcs7": {
//     "verify": {
//       "certs": [
//         {
//           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
//           "serial": "0702A21A85B84B659E180A6EE6F5A365"
//         },
//         {
//           "issuerCN": "VeriSign Class 1 Public Primary Certification Authority - G3",
//           "serial": "008B5B75568454850B00CFAF3848CEB1A4"
//         },
//         {
//           "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
//           "serial": "619C55C32FF6BD1A7B7E0330D21C8F3C"
//         }
//       ],
//       "digestAlgorithms": [
//         "sha1"
//       ],
//       "signerInfo": [
//         {
//           "cert": {
//             "serialNumber": "619C55C32FF6BD1A7B7E0330D21C8F3C",
//             "issuerCN": "Symantec Class 1 Individual Subscriber CA - G5",
//             "digestAlgOid": "1.3.14.3.2.26",
//             "digestAlgName": "SHA1"
//           },
//           "contentType": "1.2.840.113549.1.7.1",
//           "signingTime": "160428055000Z",
//           "messageDigest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY=",
//           "signingAlgOid": "1.2.840.113549.1.1.1",
//           "signingAlgName": "RSA-PKCSV-1_5",
//           "authAttr": {
//             "1.2.840.113549.1.9.3": {
//               "name": "contentType",
//               "oid": "1.2.840.113549.1.7.1"
//             },
//             "1.2.840.113549.1.9.5": {
//               "name": "signingTime",
//               "utctime": "160428055000Z"
//             },
//             "1.2.840.113549.1.9.4": {
//               "name": "messageDigest",
//               "digest": "2hJJVmO/jtaJV5uCKMFzIkRRvtY="
//             },
//             "1.2.840.113549.1.9.15": {
//               "der": "MFAwCwYJYIZIAWUDBAECMAoGCCqGSIb3DQMHMA4GCCqGSIb3DQMCAgIAgDANBggqhkiG9w0DAgIBQDAHBgUrDgMCBzANBggqhkiG9w0DAgIBKA=="
//             },
//             "1.3.6.1.4.1.311.16.4": {
//               "der": "MIG7MIG...7fgMw0hyPPA=="
//             }
//           }
//         }
//       ]
//     }
//   }
// }

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON

signingTime := CkDtObj_Create();
authAttrSigningTimeUtctime := CkDtObj_Create();

i := 0;
count_i := CkJsonObject_SizeOfArray(json,'pkcs7.verify.certs');
while i < count_i do
  begin
    CkJsonObject_putI(json,i);
    issuerCN := CkJsonObject__stringOf(json,'pkcs7.verify.certs[i].issuerCN');
    serial := CkJsonObject__stringOf(json,'pkcs7.verify.certs[i].serial');
    i := i + 1;
  end;

i := 0;
count_i := CkJsonObject_SizeOfArray(json,'pkcs7.verify.digestAlgorithms');
while i < count_i do
  begin
    CkJsonObject_putI(json,i);
    strVal := CkJsonObject__stringOf(json,'pkcs7.verify.digestAlgorithms[i]');
    i := i + 1;
  end;

i := 0;
count_i := CkJsonObject_SizeOfArray(json,'pkcs7.verify.signerInfo');
while i < count_i do
  begin
    CkJsonObject_putI(json,i);
    certSerialNumber := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].cert.serialNumber');
    certIssuerCN := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].cert.issuerCN');
    certDigestAlgOid := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].cert.digestAlgOid');
    certDigestAlgName := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].cert.digestAlgName');
    contentType := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].contentType');
    CkJsonObject_DtOf(json,'pkcs7.verify.signerInfo[i].signingTime',False,signingTime);
    messageDigest := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].messageDigest');
    signingAlgOid := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].signingAlgOid');
    signingAlgName := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].signingAlgName');
    authAttrContentTypeName := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".name');
    authAttrContentTypeOid := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".oid');
    authAttrSigningTimeName := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.5".name');
    CkJsonObject_DtOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.5".utctime',False,authAttrSigningTimeUtctime);
    authAttrMessageDigestName := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".name');
    authAttrMessageDigestDigest := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".digest');
    authAttr1_2_840_113549_1_9_15Der := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.15".der');
    authAttr1_3_6_1_4_1_311_16_4Der := CkJsonObject__stringOf(json,'pkcs7.verify.signerInfo[i].authAttr."1.3.6.1.4.1.311.16.4".der');
    i := i + 1;
  end;

CkJsonObject_Dispose(json);

CkMime_Dispose(mime);
CkDtObj_Dispose(signingTime);
CkDtObj_Dispose(authAttrSigningTimeUtctime);

end;