(Excel) RFC3161 Timestamp Client - Fetch from Timestamp Authority (TSA) and Verify

Sends an RFC 3161 timestamp request to a TSA (Timestamp Authority) server and validates the timestamp token response.

Note: This example requires Chilkat v9.5.0.75 or greater.

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' Note: Requires Chilkat v9.5.0.75 or greater.

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

' First sha-256 hash the data that is to be timestamped.
' In this example, the data is the string "Hello World"

Dim crypt As Chilkat.Crypt2
Set crypt = Chilkat.NewCrypt2
crypt.HashAlgorithm = "sha256"
crypt.EncodingMode = "base64"

base64Hash = crypt.HashStringENC("Hello World")

Dim http As Chilkat.Http
Set http = Chilkat.NewHttp

Dim requestToken As Chilkat.BinData
Set requestToken = Chilkat.NewBinData

optionalPolicyOid = ""

addNonce = False

requestTsaCert = True

' Create a time-stamp request token
success = http.CreateTimestampRequest("sha256",base64Hash,optionalPolicyOid,addNonce,requestTsaCert,requestToken)
If (success <> True) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

' Send the time-stamp request token to the TSA.
' This is the equivalent of the following CURL command:
' curl -H "Content-Type: application/timestamp-query" --data-binary '@file.tsq' https://freetsa.org/tsr > file.tsr

tsaUrl = "https://freetsa.org/tsr"
' Another timestamp server you could try is: http://timestamp.digicert.com
tsaUrl = "http://timestamp.digicert.com"

Set resp = http.PBinaryBd("POST",tsaUrl,requestToken,"application/timestamp-query",False,False)
If (http.LastMethodSuccess <> True) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

' Get the timestamp reply from the HTTP response object.
Dim timestampReply As Chilkat.BinData
Set timestampReply = Chilkat.NewBinData
Dim success As Boolean
success = resp.GetBodyBd(timestampReply)

' Show the base64 encoded timestamp reply.
Debug.Print timestampReply.GetEncoded("base64")

' Let's verify the timestamp reply against the TSA's cert, which we've previously downloaded.
' See https://freetsa.org/index_en.php
Dim tsaCert As Chilkat.Cert
Set tsaCert = Chilkat.NewCert
success = tsaCert.LoadFromFile("qa_data/certs/freetsa.org.cer")
If (success <> True) Then
    Debug.Print tsaCert.LastErrorText
    Exit Sub
End If

' The VerifyTimestampReply method will return one of the following values:
' -1:  The timestampReply does not contain a valid timestamp reply.
' -2: The  timestampReply is a valid timestamp reply, but failed verification using the public key of the tsaCert.
' 0:  Granted and verified.
' 1: Granted and verified, with mods (see RFC 3161)
' 2: Rejected.
' 3: Waiting.
' 4: Revocation Warning
' 5: Revocation Notification

pkiStatus = http.VerifyTimestampReply(timestampReply,tsaCert)
If (pkiStatus < 0) Then
    Debug.Print http.LastErrorText
    Exit Sub
End If

Debug.Print "pkiStatus = "; pkiStatus


Set json = http.LastJsonData()
json.EmitCompact = False
Debug.Print json.Emit()

' The LastJsonData looks like the following.
' Note: The "timestampReply.pkiStatus" portion of the LastJsonData was added in Chilkat v9.5.0.83

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

' {
'   "timestampReply": {
'     "pkiStatus": {
'       "value": 0,
'       "meaning": "granted"
'     }
'   },
'   "pkcs7": {
'     "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": "200405023019Z",
'           "messageDigest": "f14zOsdnN9vyyV3HjjBiLzNDi1PF28hAFMODxNkNRZs=",
'           "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": "200405023019Z"
'             },
'             "1.2.840.113549.1.9.16.2.12": {
'               "name": "signingCertificate",
'               "der": "MBowGDAWBBQDJb1QXtqWMC3CL0+gHkwovig0xQ=="
'             },
'             "1.2.840.113549.1.9.4": {
'               "name": "messageDigest",
'               "digest": "f14zOsdnN9vyyV3HjjBiLzNDi1PF28hAFMODxNkNRZs="
'             }
'           }
'         }
'       ]
'     }
'   }
' }

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


timestampReplyPkiStatusValue = json.IntOf("timestampReply.pkiStatus.value")

timestampReplyPkiStatusMeaning = json.StringOf("timestampReply.pkiStatus.meaning")

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")
    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)
    authAttrSigningCertificateName = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.""1.2.840.113549.1.9.16.2.12"".name")
    authAttrSigningCertificateDer = json.StringOf("pkcs7.verify.signerInfo[i].authAttr.""1.2.840.113549.1.9.16.2.12"".der")
    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")
    i = i + 1
Loop