Perl

Verify JWT Using HS256, HS384, or HS512

See more JSON Web Token (JWT) Examples

Demonstrates how to verify a JWT that was signed using HS256, HS384, or HS512. (HS256 is JWT's acronym for HMAC-SHA256.)

This example verifies the 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.

Chilkat2 Perl

use strict;
use warnings;
use Chilkat2;

# Demonstrates how to verify an HMAC JWT using a shared secret (password).

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

my $jwt = Chilkat2::Jwt->new;

my $token = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDMxODEyLCJuYmYiOjE0NjM0MzE4MTIsImV4cCI6MTQ2MzQzNTQxMn0.SHnMJ11qJH5pbp22YchT_9fL2HIx0koHiUHLG67_foU';

# First verify the signature.
# The password used to create this JWT was "secret".
my $sigVerified = $jwt->VerifyJwt($token, 'secret');
print 'with correct password: ', ($sigVerified ? 1 : 0), "\n";

# Now try with a different password:
$sigVerified = $jwt->VerifyJwt($token, 'secret2');
print 'with incorrect password ', ($sigVerified ? 1 : 0), "\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.
my $leeway = 60;
my $bTimeValid = $jwt->IsTimeValid($token, $leeway);
print 'time constraints valid: ', ($bTimeValid ? 1 : 0), "\n";

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

# We can format for human viewing by loading it into Chilkat's JSON object
# and emit.
my $json = Chilkat2::JsonObject->new;
my $success = $json->Load($payload);
$json->EmitCompact(0);
print $json->Emit(), "\n";

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

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