Lua Requires Chilkat v9.5.0.66+

Compute JWK Thumbprint for RSA and EC Public Keys

See more ECC Examples

Demonstrates how to compute a JSON Web Key thumbprint for a public key (RSA or ECC). Lua

local chilkat = require("chilkat")

local pubKey = chilkat.PublicKey.new()

-- A public key can be loaded from any format (binary DER, PEM, etc.)
-- This example will load the public keys from JWK format,
-- and will then compute the JWK thumbprint.

-- First do it for an RSA public key...

local sb = chilkat.StringBuilder.new()
sb:append("{")
sb:append("\"kty\": \"RSA\",")
sb:append("\"n\": \"0vx7agoebGcQSuuPiLJXZptN9nndrQmbXEps2aiAFbWhM78LhWx4cbbfAAt")
sb:append("VT86zwu1RK7aPFFxuhDR1L6tSoc_BJECPebWKRXjBZCiFV4n3oknjhMstn6")
sb:append("4tZ_2W-5JsGY4Hc5n9yBXArwl93lqt7_RN5w6Cf0h4QyQ5v-65YGjQR0_FD")
sb:append("W2QvzqY368QQMicAtaSqzs8KJZgnYb9c7d0zgdAZHzu6qMQvRL5hajrn1n9")
sb:append("1CbOpbISD08qNLyrdkt-bFTWhAI4vMQFh6WeZu0fM4lFd2NcRwr3XPksINH")
sb:append("aQ-G_xBniIqbw0Ls1jF44-csFCur-kEgU8awapJzKnqDKgw\",")
sb:append("\"e\": \"AQAB\",")
sb:append("\"alg\": \"RS256\",")
sb:append("\"kid\": \"2011-04-29\"")
sb:append("}")

-- The JWK format is automatically detected..
local success = pubKey:load_from_string(sb:get_as_string())
if not success then
    print(pubKey.last_error_text)
    return
end

-- Get the JWK thumbprint (using SHA256)
print("JWK thumbprint: " .. pubKey:get_jwk_thumbprint("SHA256"))

-- Output:
-- JWK thumbprint: NzbLsXh8uDCcd-6MNwXF4W_7noWXFZAfHkxZsRGC9Xs

-- --------------------------------------------------------------
-- Now let's do an EC public key:
sb:clear()
sb:append("{ ")
sb:append("  \"kty\": \"EC\",")
sb:append("  \"crv\": \"P-256\",")
sb:append("  \"x\": \"tDeeYABgKEAbWicYPCEEI8sP4SRIhHKcHDW7VqrB4LA\",")
sb:append("  \"y\": \"J08HOoIZ0rX2Me3bNFZUltfxIk1Hrc8FsLu8VaSxsMI\"")
sb:append("}")

success = pubKey:load_from_string(sb:get_as_string())
if not success then
    print(pubKey.last_error_text)
    return
end

-- Get the JWK thumbprint (using SHA256)
print("JWK thumbprint: " .. pubKey:get_jwk_thumbprint("SHA256"))

-- Output:
-- JWK thumbprint: 8fm8079s3nu4FLV_7dVJoJ69A8XCXn7Za2mtaWCnxR4