(PureBasic) 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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IncludeFile "CkBinData.pb"
IncludeFile "CkHttp.pb"
IncludeFile "CkCrypt2.pb"
IncludeFile "CkHttpResponse.pb"
IncludeFile "CkCert.pb"
IncludeFile "CkJsonObject.pb"
IncludeFile "CkDtObj.pb"

Procedure ChilkatExample()

    ; 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"
    success.i
    crypt.i = CkCrypt2::ckCreate()
    If crypt.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkCrypt2::setCkHashAlgorithm(crypt, "sha256")
    CkCrypt2::setCkEncodingMode(crypt, "base64")
    base64Hash.s = CkCrypt2::ckHashStringENC(crypt,"Hello World")

    http.i = CkHttp::ckCreate()
    If http.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    requestToken.i = CkBinData::ckCreate()
    If requestToken.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    optionalPolicyOid.s = ""
    addNonce.i = 0
    requestTsaCert.i = 1

    ; Create a time-stamp request token
    success = CkHttp::ckCreateTimestampRequest(http,"sha256",base64Hash,optionalPolicyOid,addNonce,requestTsaCert,requestToken)
    If success <> 1
        Debug CkHttp::ckLastErrorText(http)
        CkCrypt2::ckDispose(crypt)
        CkHttp::ckDispose(http)
        CkBinData::ckDispose(requestToken)
        ProcedureReturn
    EndIf

    ; 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.s = "https://freetsa.org/tsr"
    ; Another timestamp server you could try is: http://timestamp.digicert.com
    tsaUrl = "http://timestamp.digicert.com"
    resp.i = CkHttp::ckPBinaryBd(http,"POST",tsaUrl,requestToken,"application/timestamp-query",0,0)
    If CkHttp::ckLastMethodSuccess(http) <> 1
        Debug CkHttp::ckLastErrorText(http)
        CkCrypt2::ckDispose(crypt)
        CkHttp::ckDispose(http)
        CkBinData::ckDispose(requestToken)
        ProcedureReturn
    EndIf

    ; Get the timestamp reply from the HTTP response object.
    timestampReply.i = CkBinData::ckCreate()
    If timestampReply.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    CkHttpResponse::ckGetBodyBd(resp,timestampReply)
    CkHttpResponse::ckDispose(resp)

    ; Show the base64 encoded timestamp reply.
    Debug CkBinData::ckGetEncoded(timestampReply,"base64")

    ; Let's verify the timestamp reply against the TSA's cert, which we've previously downloaded.
    ; See https://freetsa.org/index_en.php
    tsaCert.i = CkCert::ckCreate()
    If tsaCert.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    success = CkCert::ckLoadFromFile(tsaCert,"qa_data/certs/freetsa.org.cer")
    If success <> 1
        Debug CkCert::ckLastErrorText(tsaCert)
        CkCrypt2::ckDispose(crypt)
        CkHttp::ckDispose(http)
        CkBinData::ckDispose(requestToken)
        CkBinData::ckDispose(timestampReply)
        CkCert::ckDispose(tsaCert)
        ProcedureReturn
    EndIf

    ; 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.i = CkHttp::ckVerifyTimestampReply(http,timestampReply,tsaCert)
    If pkiStatus < 0
        Debug CkHttp::ckLastErrorText(http)
        CkCrypt2::ckDispose(crypt)
        CkHttp::ckDispose(http)
        CkBinData::ckDispose(requestToken)
        CkBinData::ckDispose(timestampReply)
        CkCert::ckDispose(tsaCert)
        ProcedureReturn
    EndIf

    Debug "pkiStatus = " + Str(pkiStatus)

    json.i = CkHttp::ckLastJsonData(http)
    CkJsonObject::setCkEmitCompact(json, 0)
    Debug CkJsonObject::ckEmit(json)

    ; 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="
    ;             }
    ;           }
    ;         }
    ;       ]
    ;     }
    ;   }
    ; }

    signingTime.i = CkDtObj::ckCreate()
    If signingTime.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    authAttrSigningTimeUtctime.i = CkDtObj::ckCreate()
    If authAttrSigningTimeUtctime.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    strVal.s
    certSerialNumber.s
    certIssuerCN.s
    certDigestAlgOid.s
    certDigestAlgName.s
    contentType.s
    messageDigest.s
    signingAlgOid.s
    signingAlgName.s
    authAttrContentTypeName.s
    authAttrContentTypeOid.s
    authAttrSigningTimeName.s
    authAttrSigningCertificateName.s
    authAttrSigningCertificateDer.s
    authAttrMessageDigestName.s
    authAttrMessageDigestDigest.s

    timestampReplyPkiStatusValue.i = CkJsonObject::ckIntOf(json,"timestampReply.pkiStatus.value")
    timestampReplyPkiStatusMeaning.s = CkJsonObject::ckStringOf(json,"timestampReply.pkiStatus.meaning")
    i.i = 0
    count_i.i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.digestAlgorithms")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        strVal = CkJsonObject::ckStringOf(json,"pkcs7.verify.digestAlgorithms[i]")
        i = i + 1
    Wend
    i = 0
    count_i = CkJsonObject::ckSizeOfArray(json,"pkcs7.verify.signerInfo")
    While i < count_i
        CkJsonObject::setCkI(json, i)
        certSerialNumber = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.serialNumber")
        certIssuerCN = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.issuerCN")
        certDigestAlgOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.digestAlgOid")
        certDigestAlgName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].cert.digestAlgName")
        contentType = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].contentType")
        CkJsonObject::ckDtOf(json,"pkcs7.verify.signerInfo[i].signingTime",0,signingTime)
        messageDigest = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].messageDigest")
        signingAlgOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signingAlgOid")
        signingAlgName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].signingAlgName")
        authAttrContentTypeName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.3" + Chr(34) + ".name")
        authAttrContentTypeOid = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.3" + Chr(34) + ".oid")
        authAttrSigningTimeName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.5" + Chr(34) + ".name")
        CkJsonObject::ckDtOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.5" + Chr(34) + ".utctime",0,authAttrSigningTimeUtctime)
        authAttrSigningCertificateName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.16.2.12" + Chr(34) + ".name")
        authAttrSigningCertificateDer = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.16.2.12" + Chr(34) + ".der")
        authAttrMessageDigestName = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.4" + Chr(34) + ".name")
        authAttrMessageDigestDigest = CkJsonObject::ckStringOf(json,"pkcs7.verify.signerInfo[i].authAttr." + Chr(34) + "1.2.840.113549.1.9.4" + Chr(34) + ".digest")
        i = i + 1
    Wend

    CkJsonObject::ckDispose(json)



    CkCrypt2::ckDispose(crypt)
    CkHttp::ckDispose(http)
    CkBinData::ckDispose(requestToken)
    CkBinData::ckDispose(timestampReply)
    CkCert::ckDispose(tsaCert)
    CkDtObj::ckDispose(signingTime)
    CkDtObj::ckDispose(authAttrSigningTimeUtctime)


    ProcedureReturn
EndProcedure