(Ruby) Verify JWT Using HS256, HS384, or HS512

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.

Chilkat Ruby Downloads install from rubygems.org gem install chilkat or download... Ruby Library for Windows, MacOS, Linux, Alpine Linux

require 'chilkat'

# 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.

jwt = Chilkat::CkJwt.new()

token = "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpc3MiOiJodHRwOi8vZXhhbXBsZS5vcmciLCJzdWIiOiJKb2huIiwiYXVkIjoiaHR0cDovL2V4YW1wbGUuY29tIiwiaWF0IjoxNDYzNDMxODEyLCJuYmYiOjE0NjM0MzE4MTIsImV4cCI6MTQ2MzQzNTQxMn0.SHnMJ11qJH5pbp22YchT_9fL2HIx0koHiUHLG67_foU"

# First verify the signature.
# The password used to create this JWT was "secret".
sigVerified = jwt.VerifyJwt(token,"secret")
print "with correct password: " + sigVerified.to_s() + "\n";

# Now try with a different password:
sigVerified = jwt.VerifyJwt(token,"secret2")
print "with incorrect password " + sigVerified.to_s() + "\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.to_s() + "\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 + "\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(false)
print json.emit() + "\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 + "\n";

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