PowerShell Requires Chilkat v11.0.0+

Validate Certificate using OCSP Protocol

See more Certificates Examples

Demonstrates how to validate a certificate (check the revoked status) using the OCSP protocol. PowerShell

Add-Type -Path "C:\chilkat\ChilkatDotNet47-x64\ChilkatDotNet47.dll"

$success = $false

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

#  This example will check the revoked status of a certificate loaded from a file.
$cert = New-Object Chilkat.Cert
$success = $cert.LoadFromFile("qa_data/certs/google.crt")
if ($success -eq $false) {
    $($cert.LastErrorText)
    exit
}

#  Get the cert's OCSP URL.
$ocspUrl = $cert.OcspUrl

#  Build the JSON that will be the OCSP request.

#  Possible hash algorithms are sha1, sha256, sha384, sha512.  
$hashAlg = "sha256"
$prng = New-Object Chilkat.Prng
$json = New-Object Chilkat.JsonObject
$json.EmitCompact = $false
#  Read more about OCSP nonce lengths
$json.UpdateString("extensions.ocspNonce",$prng.GenRandom(16,"base64"))
$json.I = 0
$json.UpdateString("request[i].cert.hashAlg",$hashAlg)
$json.UpdateString("request[i].cert.issuerNameHash",$cert.HashOf("IssuerDN",$hashAlg,"base64"))
$json.UpdateString("request[i].cert.issuerKeyHash",$cert.HashOf("IssuerPublicKey",$hashAlg,"base64"))
$json.UpdateString("request[i].cert.serialNumber",$cert.SerialNumber)

$($json.Emit())

#  Our OCSP request looks something like this:
#  {
#    "extensions": {
#      "ocspNonce": "qZDfbpO+nUxRzz6c/SPjE5QCAsPfpkQlRDxTnGl0gnxt7iXO"
#    },
#    "request": [
#      {
#        "cert": {
#          "hashAlg": "sha1",
#          "issuerNameHash": "9u2wY2IygZo19o11oJ0CShGqbK0=",
#          "issuerKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
#          "serialNumber": "6175535D87BF94B6"
#        }
#      }
#    ]
#  }

$ocspRequest = New-Object Chilkat.BinData
$http = New-Object Chilkat.Http

#  Convert our JSON to a binary (ASN.1) OCSP request
$success = $http.CreateOcspRequest($json,$ocspRequest)
if ($success -eq $false) {
    $($http.LastErrorText)
    exit
}

#  Send the OCSP request to the OCSP server
$resp = New-Object Chilkat.HttpResponse
$success = $http.HttpBd("POST",$ocspUrl,$ocspRequest,"application/ocsp-request",$resp)
if ($success -eq $false) {
    $($http.LastErrorText)
    exit
}

#  Get the binary (ASN.1) OCSP reply
$ocspReply = New-Object Chilkat.BinData
$resp.GetBodyBd($ocspReply)

#  Convert the binary reply to JSON.
#  Also returns the overall OCSP response status.
$jsonReply = New-Object Chilkat.JsonObject
$ocspStatus = $http.ParseOcspReply($ocspReply,$jsonReply)

#  The ocspStatus can have one of these values:
#  -1:  The ARG1 does not contain a valid OCSP reply.
#  0:  Successful - Response has valid confirmations..
#  1: Malformed request - Illegal confirmation request.
#  2: Internal error - Internal error in issuer.
#  3: Try later -  Try again later.
#  4: Not used - This value is never returned.
#  5: Sig required - Must sign the request.
#  6: Unauthorized - Request unauthorized.

if ($ocspStatus -lt 0) {
    $("Invalid OCSP reply.")
    exit
}

$("Overall OCSP Response Status: " + $ocspStatus)

#  Let's examine the OCSP response (in JSON).
$jsonReply.EmitCompact = $false
$($jsonReply.Emit())

#  The JSON reply looks like this:
#  (Use the online tool at https://tools.chilkat.io/jsonParse.cshtml
#  to generate JSON parsing code.)

#  {
#    "responseStatus": 0,
#    "responseTypeOid": "1.3.6.1.5.5.7.48.1.1",
#    "responseTypeName": "ocspBasic",
#    "response": {
#      "responderIdChoice": "KeyHash",
#      "responderKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
#      "dateTime": "20180803193937Z",
#      "cert": [
#        {
#          "hashOid": "1.3.14.3.2.26",
#          "hashAlg": "SHA-1",
#          "issuerNameHash": "9u2wY2IygZo19o11oJ0CShGqbK0=",
#          "issuerKeyHash": "d8K4UJpndnaxLcKG0IOgfqZ+uks=",
#          "serialNumber": "6175535D87BF94B6",
#          "status": 0,
#          "thisUpdate": "20180803193937Z",
#          "nextUpdate": "20180810193937Z"
#        }
#      ]
#    }
#  }
#  

#  The certificate status:
$certStatus = -1
if ($jsonReply.HasMember("response.cert[0].status") -eq $true) {
    $certStatus = $jsonReply.IntOf("response.cert[0].status")
}

#  Possible certStatus values are:
#  -1: No status returned.
#  0: Good
#  1: Revoked
#  2: Unknown.
$("Certificate Status: " + $certStatus)