JWT public key test with CryptoGroups

JWT_test.jl

#https://www.rfc-editor.org/rfc/rfc7515#appendix-A.3

using CryptoGroups
using CryptoSignatures
using Base64

base64url_decode(x) = replace(x, "_" => "/", "-" => "+") |> base64decode
base64url_encode(x) = replace(base64encode(x), "/" => "_", "+" => "-")

# Reading in from JSON Web Key string

curve = CryptoGroups.curve("secp256r1")
P_256 = specialize(ECPoint, curve)
ctx = ECDSAContext(curve, "sha256")


x = "f83OJ3D2xF1Bg8vub9tLe1gHMzV76e8Tus9uPHvRVEU" |> base64url_decode
y = "x_FEzRu9m36HLN_tue659LNpXW6pCyStikYjKIWI5a0" |> base64url_decode

x_int = parse(BigInt, bytes2hex(x), base=16)
y_int = parse(BigInt, bytes2hex(y), base=16)

pbkey = CryptoGroups.octet(x_int, y_int, curve)
 
point = convert(P_256, pbkey)
@assert CryptoGroups.oncurve(point)

# Parsing and veryfing JWS

jws = "eyJhbGciOiJFUzI1NiJ9.eyJpc3MiOiJqb2UiLA0KICJleHAiOjEzMDA4MTkzODAsDQogImh0dHA6Ly9leGFtcGxlLmNvbS9pc19yb290Ijp0cnVlfQ.DtEhU3ljbEg8L38VWAfUAqOyKAM6-Xx-F4GawxaepmXFCgfTjDxw5djxLa8ISlSApmWQxfKTUJqPP3-Kg6NU1Q"

header, payload, signature_str = split(jws, ".")

r = base64url_decode(signature_str)[1:32]
s = base64url_decode(signature_str)[33:64]

sig = DSA(parse(BigInt, bytes2hex(r), base=16), parse(BigInt, bytes2hex(s), base=16))

input = Vector{UInt8}(header * "." * payload)

@assert CryptoSignatures.verify(ctx, input, pbkey, sig)


@assert CryptoGroups.oncurve(point)