(Ruby) Validate JWS with Multiple Signatures using the General JSON Serialization Format

Validates and recovers data and headers from a JSON Web Signature (JWS) containing 3 signatures.

Note: Chilkat supports all of the following JWS algorithms:

   +--------------+-------------------------------+--------------------+
   | "alg" Param  | Digital Signature or MAC      | Implementation     |
   | Value        | Algorithm                     | Requirements       |
   +--------------+-------------------------------+--------------------+
   | HS256        | HMAC using SHA-256            | Required           |
   | HS384        | HMAC using SHA-384            | Optional           |
   | HS512        | HMAC using SHA-512            | Optional           |
   | RS256        | RSASSA-PKCS1-v1_5 using       | Recommended        |
   |              | SHA-256                       |                    |
   | RS384        | RSASSA-PKCS1-v1_5 using       | Optional           |
   |              | SHA-384                       |                    |
   | RS512        | RSASSA-PKCS1-v1_5 using       | Optional           |
   |              | SHA-512                       |                    |
   | ES256        | ECDSA using P-256 and SHA-256 | Recommended+       |
   | ES384        | ECDSA using P-384 and SHA-384 | Optional           |
   | ES512        | ECDSA using P-521 and SHA-512 | Optional           |
   | PS256        | RSASSA-PSS using SHA-256 and  | Optional           |
   |              | MGF1 with SHA-256             |                    |
   | PS384        | RSASSA-PSS using SHA-384 and  | Optional           |
   |              | MGF1 with SHA-384             |                    |
   | PS512        | RSASSA-PSS using SHA-512 and  | Optional           |
   |              | MGF1 with SHA-512             |                    |
   +--------------+-------------------------------+--------------------+

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.

# First, prepare the public keys that will be needed for each signature.

# ---------------------------------------------------
# Use the following RSA key loaded from JWK format.
sbRsaJwk = Chilkat::CkStringBuilder.new()
sbRsaJwk.Append("{\"kty\":\"RSA\",")
sbRsaJwk.Append("\"n\":\"ofgWCuLjybRlzo0tZWJjNiuSfb4p4fAkd_wWJcyQoTbji9k0l8W26mPddx")
sbRsaJwk.Append("HmfHQp-Vaw-4qPCJrcS2mJPMEzP1Pt0Bm4d4QlL-yRT-SFd2lZS-pCgNMs")
sbRsaJwk.Append("D1W_YpRPEwOWvG6b32690r2jZ47soMZo9wGzjb_7OMg0LOL-bSf63kpaSH")
sbRsaJwk.Append("SXndS5z5rexMdbBYUsLA9e-KXBdQOS-UTo7WTBEMa2R2CapHg665xsmtdV")
sbRsaJwk.Append("MTBQY4uDZlxvb3qCo5ZwKh9kG4LT6_I5IhlJH7aGhyxXFvUK-DWNmoudF8")
sbRsaJwk.Append("NAco9_h9iaGNj8q2ethFkMLs91kzk2PAcDTW9gb54h4FRWyuXpoQ\",")
sbRsaJwk.Append("\"e\":\"AQAB\"")
sbRsaJwk.Append("}")

rsaKey = Chilkat::CkPublicKey.new()
success = rsaKey.LoadFromString(sbRsaJwk.getAsString())
if (success != true)
    print rsaKey.lastErrorText() + "\n";
    exit
end

# ---------------------------------------------------
# Use the following ECC public key loaded from JWK format.
sbEccJwk = Chilkat::CkStringBuilder.new()
sbEccJwk.Append("{\"kty\":\"EC\",")
sbEccJwk.Append("\"crv\":\"P-256\",")
sbEccJwk.Append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",")
sbEccJwk.Append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\"")
sbEccJwk.Append("}")

eccKey = Chilkat::CkPublicKey.new()
success = eccKey.LoadFromString(sbEccJwk.getAsString())
if (success != true)
    print eccKey.lastErrorText() + "\n";
    exit
end

# ---------------------------------------------------
# The HMAC key (in base64url format)
hmacKey = "AyM1SysPpbyDfgZld3umj1qzKObwVMkoqQ-EstJQLr_T-1qS0gZH75aKtMN3Yj0iPS4hcgUuTwjAzZr1Z9CAow"

# The code below will verify each of the signatures in this JWS:

# { 
#   "payload": "SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu",
#   "signatures": [
#     { 
#       "protected": "eyJhbGciOiJSUzI1NiIsImtpZCI6Im15UnNhS2V5In0",
#       "signature": "IPMQ02niTQDwLzsRZSCaEm9VEyAX_AVe3HWjniNt9kW-a8d6ZVbd2k6jGae8s1yIh0cgxDnXQ6-p6_sBI0cnMO0xpuJANhh2vFtNJl5lisad94-H3mB3lSfafRqxeYp5D8bh39BPv7y3PrUNVMQdKEJp_D5oJ0ROPTIYx3EG8eJQOx1HO0KqhcUo401XR6KSsIyFm5joBLNKTVzxZUTT1RRZZtwTdeZkbGevugIOX_9gHAtARpV6WaFA4Vvjnq8X9wPgqjWNCQRupadhTPz0JAsa-wy5vXQjsFlXAn43mDPpMfna5Ab3F5pS4yDwkbX6nRn7XBxH1SnnNJRFholQZw"
#     },
#     { 
#       "protected": "eyJhbGciOiJFUzI1NiIsImtpZCI6Im15RWNLZXkifQ",
#       "signature": "1OQtaT3pgZmkDxvlfghvxL_8kX16WIen6u1MadEq1pA4qytA0--_EwZDNk00GDPWFpoJtKznibMZzLOg_UhHIw"
#     },
#     { 
#       "protected": "eyJhbGciOiJIUzI1NiIsImtpZCI6Im15TWFjS2V5In0",
#       "signature": "YY8yVjmJJfy7YJOn3uUydG8WCY2PEuCvOLil5Ks5lnw"
#     }
#   ]
# }

sbJws = Chilkat::CkStringBuilder.new()
sbJws.Append("{ ")
sbJws.Append("  \"payload\": \"SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu\",")
sbJws.Append("  \"signatures\": [")
sbJws.Append("    { ")
sbJws.Append("      \"protected\": \"eyJhbGciOiJSUzI1NiIsImtpZCI6Im15UnNhS2V5In0\",")
sbJws.Append("      \"signature\": \"IPMQ02niTQDwLzsRZSCaEm9VEyAX_AVe3HWjniNt9kW-a8d6ZVbd2k6jGae8s1yIh0cgxDnXQ6-p6_sBI0cnMO0xpuJANhh2vFtNJl5lisad94-H3mB3lSfafRqxeYp5D8bh39BPv7y3PrUNVMQdKEJp_D5oJ0ROPTIYx3EG8eJQOx1HO0KqhcUo401XR6KSsIyFm5joBLNKTVzxZUTT1RRZZtwTdeZkbGevugIOX_9gHAtARpV6WaFA4Vvjnq8X9wPgqjWNCQRupadhTPz0JAsa-wy5vXQjsFlXAn43mDPpMfna5Ab3F5pS4yDwkbX6nRn7XBxH1SnnNJRFholQZw\"")
sbJws.Append("    },")
sbJws.Append("    { ")
sbJws.Append("      \"protected\": \"eyJhbGciOiJFUzI1NiIsImtpZCI6Im15RWNLZXkifQ\",")
sbJws.Append("      \"signature\": \"1OQtaT3pgZmkDxvlfghvxL_8kX16WIen6u1MadEq1pA4qytA0--_EwZDNk00GDPWFpoJtKznibMZzLOg_UhHIw\"")
sbJws.Append("    },")
sbJws.Append("    { ")
sbJws.Append("      \"protected\": \"eyJhbGciOiJIUzI1NiIsImtpZCI6Im15TWFjS2V5In0\",")
sbJws.Append("      \"signature\": \"YY8yVjmJJfy7YJOn3uUydG8WCY2PEuCvOLil5Ks5lnw\"")
sbJws.Append("    }")
sbJws.Append("  ]")
sbJws.Append("}")

jws = Chilkat::CkJws.new()

success = jws.LoadJwsSb(sbJws)
if (success != true)
    print jws.lastErrorText() + "\n";
    exit
end

# The payload is easily accessible:
print "Payload: " + jws.getPayload("utf-8") + "\n";

sbKeyId = Chilkat::CkStringBuilder.new()
bCaseSensitive = false

numSignatures = jws.get_NumSignatures()
i = 0
while i < numSignatures
    # protHeader is a CkJsonObject
    protHeader = jws.GetProtectedHeader(i)

    print "--------------------------" + "\n";
    print i.to_s() + ": " + "\n";

    # Get the protected header.
    protHeader.put_EmitCompact(false)
    print protHeader.emit() + "\n";

    # Get the key ID ("kid") member.

    # Note: In this example, the "kid" values are contained in the protected headers.
    # They could've just as easily been located in unprotected headers.  In that case,
    # we would've called GetUnprotectedHeader(i) instead of GetProtectedHeader(i).

    sbKeyId.Clear()
    sbKeyId.Append(protHeader.stringOf("kid"))

    # Set the key based on key ID.
    if (sbKeyId.ContentsEqual("myRsaKey",bCaseSensitive) == true)
        jws.SetPublicKey(i,rsaKey)
    end

    if (sbKeyId.ContentsEqual("myEcKey",bCaseSensitive) == true)
        jws.SetPublicKey(i,eccKey)
    end

    if (sbKeyId.ContentsEqual("myMacKey",bCaseSensitive) == true)
        jws.SetMacKey(i,hmacKey,"base64url")
    end

    # Validate this signature.
    v = jws.Validate(i)
    if (v < 0)
        # Perhaps Chilkat was not unlocked or the trial expired..
        print "Validate failed for some other reason." + "\n";
        print jws.lastErrorText() + "\n";
    else
        if (v == 0)
            print "Invalid signature.  The key was incorrect, the JWS was invalid, or both." + "\n";
        else
            print "Signature validated." + "\n";
        end

    end

    i = i + 1
end

# The output of this program is:

# 	Payload: In our village, folks say God crumbles up the old moon into stars.
# 	--------------------------
# 	0: 
# 	{
# 	  "alg": "RS256",
# 	  "kid": "myRsaKey"
# 	}
# 
# 	Signature validated.
# 	--------------------------
# 	1: 
# 	{
# 	  "alg": "ES256",
# 	  "kid": "myEcKey"
# 	}
# 
# 	Signature validated.
# 	--------------------------
# 	2: 
# 	{
# 	  "alg": "HS256",
# 	  "kid": "myMacKey"
# 	}
# 
# 	Signature validated.