Lua

RSA Sign utf-8 Bytes of String to get Base64 RSA Signature

See more Apple Keychain Examples

Demonstrates how RSA sign the utf-8 byte representation of a string to get the signature in base64 format. 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 cert: " .. cert.subject_cn)

-- Create a string to be hashed and signed.
local sb = chilkat.StringBuilder.new()
local crlfLineEnding = true
for i = 0, 10 do
    sb:append_line("This is a test.", crlfLineEnding)
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

-- Sign the SHA-256 hash of the utf-8 byte representation of the contents of sb
-- Return the signature in base64 format.
rsa.encoding_mode = "base64"
rsa.charset = "utf-8"
local stringToSign = sb:get_as_string()
local sigBase64 = rsa:sign_string_enc(stringToSign, "sha256")
if not rsa.last_method_success then
    print(rsa.last_error_text)
    return
end

print("RSA signature as base64: " .. sigBase64)