(Ruby) Create a JWS Using ECDSA P-521 SHA-512

Creates and verifies a JSON Web Signature (JWS) that uses ECDSA P-521 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.

# Use the following ECC key loaded from JWK format.
sbJwk = Chilkat::CkStringBuilder.new()
sbJwk.Append("{\"kty\":\"EC\",")
sbJwk.Append("\"crv\":\"P-521\",")
sbJwk.Append("\"x\":\"AekpBQ8ST8a8VcfVOTNl353vSrDCLLJXmPk06wTjxrrjcBpXp5EOnYG_NjFZ6OvLFV1jSfS9tsz4qUxcWceqwQGk\",")
sbJwk.Append("\"y\":\"ADSmRA43Z1DSNx_RvcLI87cdL07l6jQyyBXMoxVg_l2Th-x3S1WDhjDly79ajL4Kkd0AZMaZmh9ubmf63e3kyMj2\",")
sbJwk.Append("\"d\":\"AY5pb7A0UFiB3RELSD64fTLOSV_jazdF7fLYyuTw8lOfRhWg6Y6rUrPAxerEzgdRhajnu0ferB0d53vM9mE15j2C\"")
sbJwk.Append("}")

eccKey = Chilkat::CkPrivateKey.new()
# Note: This example loads the ECDSA key from JWK format.  Any format can be loaded
# into the private key object. (See the online reference documentation..)
success = eccKey.LoadJwk(sbJwk.getAsString())
if (success != true)
    print eccKey.lastErrorText() + "\n";
    exit
end

# Create the JWS Protected Header
jwsProtHdr = Chilkat::CkJsonObject.new()
jwsProtHdr.AppendString("alg","ES512")

jws = Chilkat::CkJws.new()

# Set the protected header:
signatureIndex = 0
jws.SetProtectedHeader(signatureIndex,jwsProtHdr)

# Set the ECC key:
jws.SetPrivateKey(signatureIndex,eccKey)

# Set the payload.
bIncludeBom = false
payloadStr = "In our village, folks say God crumbles up the old moon into stars."
jws.SetPayload(payloadStr,"utf-8",bIncludeBom)

# Create the JWS
# By default, the compact serialization is used.
jwsCompact = jws.createJws()
if (jws.get_LastMethodSuccess() != true)
    print jws.lastErrorText() + "\n";
    exit
end

print "JWS: " + jwsCompact + "\n";

# Note: ECC signatures use random values, so the output will be different each time a signature is produced.
# sample output:
# JWS: eyJhbGciOiJFUzUxMiJ9.SW4gb3VyIHZpbGxhZ2UsIGZvbGtzIHNheSBHb2QgY3J1bWJsZXMgdXAgdGhlIG9sZCBtb29uIGludG8gc3RhcnMu.AFOnOtZ8UTp-ed1PfLfXxwGU7zT_jnmGGxew-d1CP6SfKa5RUhav5mF4szhSof22JaoQ742VIa0eZ0s1rhBnj8y6APr6g6vKzIpYZlJsnjzjUwAjDQOLmcsjxrrRfATh-NEv7G0Z9FrjdJasS44tCG2EnG6aT2TW-sPG0dy5o9jUWCzi

# Now load the JWS, validate, and recover the original text.
jws2 = Chilkat::CkJws.new()

# Load the JWS.
success = jws2.LoadJws(jwsCompact)

# eccPubKey is a CkPublicKey
eccPubKey = eccKey.GetPublicKey()

# Set the ECC public key used for validation.
signatureIndex = 0
jws2.SetPublicKey(signatureIndex,eccPubKey)

# Validate the 1st (and only) signature at index 0..
v = jws2.Validate(signatureIndex)
if (v < 0)
    # Perhaps Chilkat was not unlocked or the trial expired..
    print "Method call failed for some other reason." + "\n";
    print jws2.lastErrorText() + "\n";
    exit
end

if (v == 0)
    print "Invalid signature.  The ECC 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 jws2.getPayload("utf-8") + "\n";

# Examine the protected header:
# joseHeader is a CkJsonObject
joseHeader = jws2.GetProtectedHeader(signatureIndex)
if (jws2.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.
# 	In our village, folks say God crumbles up the old moon into stars.
# 	Protected (JOSE) header:
# 	{
# 	  "alg": "ES512"
# 	}