(Lianja) 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.

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

loMime = createobject("CkMime")

// Load the signed MIME from a file...
llSuccess = loMime.LoadMimeFile("qa_data/mime/detached_sig.eml")
if (llSuccess = .F.) then
    ? loMime.LastErrorText
    release loMime
    return
endif

// Verify the S/MIME and restore the MIME
// to the structure/content it had prior to signing.
llVerified = loMime.Verify()
if (llVerified = .F.) then
    ? loMime.LastErrorText
    release loMime
    return
endif

// Examine the details of what was verified.
loJson = loMime.LastJsonData()
loJson.EmitCompact = .F.
? loJson.Emit()

// 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

loSigningTime = createobject("CkDtObj")
loAuthAttrSigningTimeUtctime = createobject("CkDtObj")

i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.certs")
do while i < lnCount_i
    loJson.I = i
    lcIssuerCN = loJson.StringOf("pkcs7.verify.certs[i].issuerCN")
    lcSerial = loJson.StringOf("pkcs7.verify.certs[i].serial")
    i = i + 1
enddo
i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.digestAlgorithms")
do while i < lnCount_i
    loJson.I = i
    lcStrVal = loJson.StringOf("pkcs7.verify.digestAlgorithms[i]")
    i = i + 1
enddo
i = 0
lnCount_i = loJson.SizeOfArray("pkcs7.verify.signerInfo")
do while i < lnCount_i
    loJson.I = i
    lcCertSerialNumber = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.serialNumber")
    lcCertIssuerCN = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.issuerCN")
    lcCertDigestAlgOid = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgOid")
    lcCertDigestAlgName = loJson.StringOf("pkcs7.verify.signerInfo[i].cert.digestAlgName")
    lcContentType = loJson.StringOf("pkcs7.verify.signerInfo[i].contentType")
    loJson.DtOf("pkcs7.verify.signerInfo[i].signingTime",.F.,loSigningTime)
    lcMessageDigest = loJson.StringOf("pkcs7.verify.signerInfo[i].messageDigest")
    lcSigningAlgOid = loJson.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
    lcSigningAlgName = loJson.StringOf("pkcs7.verify.signerInfo[i].signingAlgName")
    lcAuthAttrContentTypeName = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".name')
    lcAuthAttrContentTypeOid = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.3".oid')
    lcAuthAttrSigningTimeName = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.5".name')
    loJson.DtOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.5".utctime',.F.,loAuthAttrSigningTimeUtctime)
    lcAuthAttrMessageDigestName = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".name')
    lcAuthAttrMessageDigestDigest = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.4".digest')
    lcAuthAttr1_2_840_113549_1_9_15Der = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.2.840.113549.1.9.15".der')
    lcAuthAttr1_3_6_1_4_1_311_16_4Der = loJson.StringOf('pkcs7.verify.signerInfo[i].authAttr."1.3.6.1.4.1.311.16.4".der')
    i = i + 1
enddo

release loJson


release loMime
release loSigningTime
release loAuthAttrSigningTimeUtctime