(PowerShell) Verify JWT with EdDSA / Ed25519 Signature

Note: This example requires Chilkat v9.5.0.84 or greater.

Demonstrates how to verify a JWT that was signed using an Ed25519 private key.

This example verifies the EdDSA 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 data.

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

# Demonstrates how to verify a JWT with an EdDSA/Ed25519 Signature
# *** Requires Chilkat v9.5.0.84 or greater.

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

# Use this Ed25519 public key for verification

$jsonPubKey = "{`"kty`": `"OKP`",`"alg`": `"EdDSA`",`"crv`": `"Ed25519`",`"x`": `"11qYAYKxCrfVS_7TyWQHOg7hcvPapiMlrwIaaPcHURo`"}"

$pubKey = New-Object Chilkat.PublicKey
$success = $pubKey.LoadFromString($jsonPubKey)
if ($success -eq $false) {
    $($pubKey.LastErrorText)
    exit
}

$jwt = New-Object Chilkat.Jwt
$token = "eyJhbGciOiJFZERTQSJ9.RXhhbXBsZSBvZiBFZDI1NTE5IHNpZ25pbmc.hgyY0il_MGCjP0JzlnLWG1PPOt7-09PGcvMg3AIbQR6dWbhijcNR4ki4iylGjg5BhVsPt9g7sVvpAr_MuM0KAg"

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

if ($sigVerified -eq $false) {
    $($jwt.LastErrorText)
    exit
}

# 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)

# Recover the original data (the payload).
$payload = $jwt.GetPayload($token)
$($payload)

# Recover the original JOSE header in the same way:
$joseHeader = $jwt.GetHeader($token)
$($joseHeader)