Lua

RSA Sign an Encoded Hash

See more RSA Examples

Demonstrates signing a hash (e.g., SHA256) provided as an encoded string (e.g., base64 or hex). Lua

local chilkat = require("chilkat")

-- Assuming the smartcard/USB token is installed with the correct drivers from the manufacturer,
-- this code can work on multiple platforms including Windows, MacOS, Linux, and iOS.

-- Chilkat automatically detects and determines the way in which the HSM is used,
-- which can be by PKCS11, Apple Keychain, Microsoft CNG / Crypto API, or ScMinidriver.

local cert = chilkat.Cert.new()

-- Set the token/smartcard PIN prior to loading.
cert.smart_card_pin = "123456"

-- Specify the certificate by its common name.
local success = cert:load_from_smartcard("cn=chilkat-rsa-2048")
if not success then
    print(cert.last_error_text)
    return
end

print("Signing with the private key for this cert: " .. cert.subject_cn)

-- Create data to be hashed and signed.
local bd = chilkat.BinData.new()
for i = 0, 100 do
    bd:append_encoded("000102030405060708090A0B0C0D0E0F", "hex")
end

local rsa = chilkat.Rsa.new()

-- Use the certificate's private key for signing.
success = rsa:set_x509_cert(cert, true)
if not success then
    print(rsa.last_error_text)
    return
end

-- We'll first compute the hash and then pass the encoded hash to be signed.
local sha256_base64 = bd:get_hash("sha256", "base64")
print("sha256 hash in base64 format: " .. sha256_base64)

-- Pass in the base64 hash and return a base64 signature.
rsa.encoding_mode = "base64"
local rsaSig_base64 = rsa:sign_hash_enc(sha256_base64, "sha256")
if not success then
    print(rsa.last_error_text)
    return
end

print("RSA signature as base64: " .. rsaSig_base64)