(Excel) 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.

Dim mime As Chilkat.Mime
Set mime = Chilkat.NewMime

' Load the signed MIME from a file...

success = mime.LoadMimeFile("qa_data/mime/detached_sig.eml")
If (success = False) Then
    Debug.Print mime.LastErrorText
    Exit Sub
End If

' Verify the S/MIME and restore the MIME
' to the structure/content it had prior to signing.

verified = mime.Verify()
If (verified = False) Then
    Debug.Print mime.LastErrorText
    Exit Sub
End If

' Examine the details of what was verified.

Set json = mime.LastJsonData()
json.EmitCompact = False
Debug.Print json.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

Dim signingTime As Chilkat.DtObj
Set signingTime = Chilkat.NewDtObj
Dim authAttrSigningTimeUtctime As Chilkat.DtObj
Set authAttrSigningTimeUtctime = Chilkat.NewDtObj


i = 0

count_i = json.SizeOfArray("pkcs7.verify.certs")
Do While i < count_i
    json.I = i
    issuerCN = json.StringOf("pkcs7.verify.certs[i].issuerCN")
    serial = json.StringOf("pkcs7.verify.certs[i].serial")
    i = i + 1
Loop
i = 0
count_i = json.SizeOfArray("pkcs7.verify.digestAlgorithms")
Do While i < count_i
    json.I = i
    strVal = json.StringOf("pkcs7.verify.digestAlgorithms[i]")
    i = i + 1
Loop
i = 0
count_i = json.SizeOfArray("pkcs7.verify.signerInfo")
Do While i < count_i
    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")
    Dim success As Boolean
    success = json.DtOf("pkcs7.verify.signerInfo[i].signingTime",False,signingTime)
    messageDigest = json.StringOf("pkcs7.verify.signerInfo[i].messageDigest")
    signingAlgOid = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgOid")
    signingAlgName = json.StringOf("pkcs7.verify.signerInfo[i].signingAlgName")
    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")
    authAttrSigningTimeName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.""1.2.840.113549.1.9.5"".name")
    success = json.DtOf("pkcs7.verify.signerInfo[i].authAttr.""1.2.840.113549.1.9.5"".utctime",False,authAttrSigningTimeUtctime)
    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")
    authAttr1_2_840_113549_1_9_15Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.""1.2.840.113549.1.9.15"".der")
    authAttr1_3_6_1_4_1_311_16_4Der = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.""1.3.6.1.4.1.311.16.4"".der")
    i = i + 1
Loop