Perl

Verify a JWT Created by the Amazon Cognito Service

See more JSON Web Token (JWT) Examples

Demonstrates how to verify a JWT created by the Amazon Cognito Service. Perl

use chilkat();

$success = 0;

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

# The public keys for this example are at https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json
# Let's get them:

$http = chilkat::CkHttp->new();
$sbJsonKeys = chilkat::CkStringBuilder->new();
$success = $http->QuickGetSb("https://cognito-idp.us-east-2.amazonaws.com/us-east-2_******/.well-known/jwks.json",$sbJsonKeys);
if ($success == 0) {
    print $http->lastErrorText() . "\r\n";
    exit;
}

$jsonKeys = chilkat::CkJsonObject->new();
$jsonKeys->LoadSb($sbJsonKeys);
$jsonKeys->put_EmitCompact(0);
print $jsonKeys->emit() . "\r\n";

# Here are the keys:

# {
#   "keys": [
#     {
#       "alg": "RS256",
#       "e": "AQAB",
#       "kid": "1A/L5Fsb2EsEwxy5E0cmCMS1BnMe6Jl6NXiMig4iNwU=",
#       "kty": "RSA",
#       "n": "y0w7BJrIJYi ... jKG27z2P3OKw",
#       "use": "sig"
#     },
#     {
#       "alg": "RS256",
#       "e": "AQAB",
#       "kid": "mos6VTJnvDwurY3ghJg6IAPUq+dMwl6CL/iThzJOkzg=",
#       "kty": "RSA",
#       "n": "qbIEH-7tg6yrT ... 3Fj94ooTd0w",
#       "use": "sig"
#     }
#   ]
# }

# Try the 1st key.
$jsonKey1 = chilkat::CkJsonObject->new();
$jsonKeys->ObjectOf2("keys[0]",$jsonKey1);

$pubKey1 = chilkat::CkPublicKey->new();
$success = $pubKey1->LoadFromString($jsonKey1->emit());
if ($success == 0) {
    print $pubKey1->lastErrorText() . "\r\n";
    exit;
}

print "Success" . "\r\n";

$jwt = chilkat::CkJwt->new();

# I did not include the an actual AWS Cognito token here because our test sample used customer-provided data..
$token = "eyJ..asXg";

# First verify the signature.
$sigVerified = $jwt->VerifyJwtPk($token,$pubKey1);
print "verified: " . $sigVerified . "\r\n";

# 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);
print "time constraints valid: " . $bTimeValid . "\r\n";

# Now let's recover the original claims JSON (the payload).
$payload = $jwt->getPayload($token);
# The payload will likely be in compact form:
print $payload . "\r\n";

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
$json = chilkat::CkJsonObject->new();
$success = $json->Load($payload);
$json->put_EmitCompact(0);
print $json->emit() . "\r\n";

# We can recover the original JOSE header in the same way:
$joseHeader = $jwt->getHeader($token);
# The payload will likely be in compact form:
print $joseHeader . "\r\n";

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
$success = $json->Load($joseHeader);
$json->put_EmitCompact(0);
print $json->emit() . "\r\n";