(PowerShell) Verify JWT Using an RSA Public Key (RS256, RS384, RS512)

Demonstrates how to verify a JWT that was signed using an RSA private key.

This example verifies the RSA signature. It also does the following:

• Checks to see if the time constraints ("nbf" and "exp") are valid.
• Recovers the original JOSE header.
• Recovers the original claims JSON.

Chilkat .NET Downloads Chilkat .NET Assemblies

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

# Demonstrates how to verify an JWT using an RSA public key.

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

$pubKey = New-Object Chilkat.PublicKey
$success = $pubKey.LoadFromFile("qa_data/pem/rsa_public.pem")

$jwt = New-Object Chilkat.Jwt

$token = "eyJhbGciOiJSUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDQ1MjM4LCJuYmYiOjE0NjM0NDUyMzgsImV4cCI6MTQ2MzQ0ODgzOH0.XRtqed6nuJ9lrp0wbNdDX3fCkSh_d9cHAniPbNcqm7G-5N3mtI5ntQvZBDP3pHtECVqufuDwW7XgUtzAi0ZXhyiRm1iZ3wMSN5lHWv52OQJmMHPA7VPd8Q1hDG-tx-QswzJKd75OEUHP7wIXq2Mg_YVElfDvJI6TGjGyS1y-RLHlz-ldlGsEwIBkO0PtzIYTVov97x8p9KCsPNhS4lZUIqKOYoTZUV5LpuAWARl-636DfMEB_A5_IEaw_W8leh2suP2ULVZxwE-Tk1kBC9tsSGrBrPTtg7sziaV4Lbb0JRANmh98uTRu5f8ji9CVOnpbMiAzjsJSy56kz_olweXSuA"

# First verify the signature.
$sigVerified = $jwt.VerifyJwtPk($token,$pubKey)
$("verified: " + $sigVerified)

# Let's see if the time constraints, if any, are valid.
# The above JWT was created on the afternoon of 16-May-2016, with an expiration of 1 hour.
# If the current system time is before the "nbf" time, or after the "exp" time,
# then IsTimeValid will return false/0.
# Also, we'll allow a leeway of 60 seconds to account for any clock skew.
# Note: If the token has no "nbf" or "exp" claim fields, then IsTimeValid is always true.
$leeway = 60
$bTimeValid = $jwt.IsTimeValid($token,$leeway)
$("time constraints valid: " + $bTimeValid)

# Now let's recover the original claims JSON (the payload).
$payload = $jwt.GetPayload($token)
# The payload will likely be in compact form:
$($payload)

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
$json = New-Object Chilkat.JsonObject
$success = $json.Load($payload)
$json.EmitCompact = $false
$($json.Emit())

# We can recover the original JOSE header in the same way:
$joseHeader = $jwt.GetHeader($token)
# The payload will likely be in compact form:
$($joseHeader)

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
$success = $json.Load($joseHeader)
$json.EmitCompact = $false
$($json.Emit())