Ruby Requires Chilkat v11.0.0+

Validate a JWS Using ECDSA P-256 SHA-256

See more JSON Web Signatures (JWS) Examples

Validates a JSON Web Signature (JWS) that uses ECDSA P-256 SHA-256 Ruby

require 'chilkat'

success = false

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

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

#  We only need a public key for signature validation.  This is the ECDSA public key
#  that is used:

#       {"kty":"EC", 
#        "crv":"P-256", 
#        "x":"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU", 
#        "y":"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" 
#       } 

sbPubKey = Chilkat::CkStringBuilder.new()
sbPubKey.Append("{\"kty\":\"EC\",")
sbPubKey.Append("\"crv\":\"P-256\",")
sbPubKey.Append("\"x\":\"f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU\",")
sbPubKey.Append("\"y\":\"x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0\"")
sbPubKey.Append("}")

pubKey = Chilkat::CkPublicKey.new()
success = pubKey.LoadFromString(sbPubKey.getAsString())
if (success == false)
    print pubKey.lastErrorText() + "\n";
    exit
end

jws = Chilkat::CkJws.new()

#  Set the ECC public key:
signatureIndex = 0
jws.SetPublicKey(signatureIndex,pubKey)

#  Load the JWS.
sbJws = Chilkat::CkStringBuilder.new()
sbJws.Append("eyJhbGciOiJFUzI1NiJ9")
sbJws.Append(".")
sbJws.Append("eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFt")
sbJws.Append("cGxlLmNvbS9pc19yb290Ijp0cnVlfQ")
sbJws.Append(".")
sbJws.Append("DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSA")
sbJws.Append("pmWQxfKTUJqPP3-Kg6NU1Q")

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

#  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 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";
print "--" + "\n";

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

#  Examine the protected header:

joseHeader = Chilkat::CkJsonObject.new()
success = jws.GetProtectedH(signatureIndex,joseHeader)
if (success == false)
    print jws.lastErrorText() + "\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:
#  	{ 
#  	  "alg": "ES256"
#  	}