(Ruby) Validate JWS Using HMAC SHA-256

Validates a JSON Web Signature (JWS) using HMAC SHA-256.

Note: This example requires Chilkat v9.5.0.66 or greater.

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

require 'chilkat'

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

# Note: This example requires Chilkat v9.5.0.66 or greater.

# This example takes a JSON signature in compact serialization format,
# and uses a MAC key to validate and recover the protected header and payload.

jws = Chilkat::CkJws.new()

# Set the HMAC key:
hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"
signatureIndex = 0
jws.SetMacKey(signatureIndex,hmacKey,"base64url")

# Load the JWS.
jwsCompact = "eyJ0eXAiOiJKV1QiLA0KICJhbGciOiJIUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.dBjftJeZ4CVP-mB92K27uhbUJU1p1r_wW1gFWFOEjXk"
success = jws.LoadJws(jwsCompact)

# Validate the 1st (and only) signature at index 0..
v = jws.Validate(signatureIndex)
if (v < 0)
    # Perhaps Chilkat was not unlocked or the trial expired..
    print "Method call failed for some other reason." + "\n";
    print jws.lastErrorText() + "\n";
    exit
end

if (v == 0)
    print "Invalid signature.  The MAC key was incorrect, the JWS was invalid, or both." + "\n";
    exit
end

# If we get here, the signature was validated..
print "Signature validated." + "\n";

# Recover the original content:
print "Recovered content:" + "\n";
print jws.getPayload("utf-8") + "\n";

# Examine the protected header:
# joseHeader is a CkJsonObject
joseHeader = jws.GetProtectedHeader(signatureIndex)
if (jws.get_LastMethodSuccess() != true)
    print "No protected header found at the given index." + "\n";
    exit
end

joseHeader.put_EmitCompact(false)

print "Protected (JOSE) header:" + "\n";
print joseHeader.emit() + "\n";

# Output:

# 	Signature validated.
# 	Recovered content:
# 	{"iss":"joe",
# 	 "exp":1300819380,
# 	 "http://example.com/is_root":true}
# 	Protected (JOSE) header:
# 	{ 
# 	  "typ": "JWT",
# 	  "alg": "HS256"
# 	}