(PowerShell) Decode Microsoft Graph ID Token

Demonstrates how to decode a Microsoft Graph ID token.

Chilkat .NET Downloads Chilkat .NET Assemblies

Add-Type -Path "C:\chilkat\ChilkatDotNet47-9.5.0-x64\ChilkatDotNet47.dll"

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

# In a previous example, we obtained a Microsoft Graph OAuth2 access token.
# This example loads the JSON saved from the previous example and decodes the id_token.

# Our Microsoft Graph OAuth2 token looks like this:

# {
#   "token_type": "Bearer",
#   "scope": "openid profile User.ReadWrite Mail.ReadWrite Mail.Send Files.ReadWrite User.Read Calendars.ReadWrite Group.ReadWrite.All",
#   "expires_in": 3600,
#   "ext_expires_in": 3600,
#   "access_token": "EwCQA8l6...0HhMKYwC",
#   "refresh_token": "MCWulIvzi2yD0S...igEFn51mqcByhZtAJg",
#   "id_token": "eyJ0eXAiOiJKV1...Q7lRDaR-7A",
#   "expires_on": "1562862714"
# }

$jsonToken = New-Object Chilkat.JsonObject
$success = $jsonToken.LoadFile("qa_data/tokens/microsoftGraph.json")
if ($success -eq $false) {
    $("Failed to load the JSON file...")
    exit
}

# Use Chilkat's JWT API to examine the id_token..
$jwt = New-Object Chilkat.Jwt
$idToken = $jsonToken.StringOf("id_token")

# Extract the JOSE header..
$jose = $jwt.GetHeader($idToken)

$jsonHeader = New-Object Chilkat.JsonObject
$jsonHeader.Load($jose)
$jsonHeader.EmitCompact = $false
$($jsonHeader.Emit())

# The JOSE header looks like this:

# {
#   "typ": "JWT",
#   "alg": "RS256",
#   "kid": "1LTMzakihiRla_8z2BEJVXeWMqo"
# }

$claims = $jwt.GetPayload($idToken)

$jsonClaims = New-Object Chilkat.JsonObject
$jsonClaims.Load($claims)
$jsonClaims.EmitCompact = $false
$($jsonClaims.Emit())

# The claims look like this:

# {
#   "ver": "2.0",
#   "iss": "https://login.microsoftonline.com/9188040d-6c67-4c5b-b112-36a304b66dad/v2.0",
#   "sub": "AAAAAAAAAAAAAAAAAAAAAHJFryd6Gydo-XtTd1nhUNQ",
#   "aud": "18c456bd-db75-43fe-9724-9e5d821c68ff",
#   "exp": 1562945513,
#   "iat": 1562858813,
#   "nbf": 1562858813,
#   "name": "Matt Chilkat",
#   "preferred_username": "matt@example.com",
#   "oid": "00000000-0000-0000-3a33-fceb9b74cc15",
#   "tid": "9188040d-6c67-4c5b-b112-36a304b66dad",
#   "aio": "DfibJqKnWC1c0FS6G ... W6pvTrQuYzyq16ghY$"
# }
# 

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

# Get each of the claims..
$ver = $jsonClaims.StringOf("ver")
$iss = $jsonClaims.StringOf("iss")
$s_sub = $jsonClaims.StringOf("sub")
$aud = $jsonClaims.StringOf("aud")
$exp = $jsonClaims.IntOf("exp")
$iat = $jsonClaims.IntOf("iat")
$nbf = $jsonClaims.IntOf("nbf")
$name = $jsonClaims.StringOf("name")
$preferred_username = $jsonClaims.StringOf("preferred_username")
$oid = $jsonClaims.StringOf("oid")
$tid = $jsonClaims.StringOf("tid")
$aio = $jsonClaims.StringOf("aio")