Lua

Export a Public Key as PEM

Demonstrates the Chilkat PublicKey.GetPem method, which returns the public key in PEM format. The only argument selects the underlying DER representation: true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.

Note: The file paths are relative to the application's current working directory. Absolute paths may also be used. Supply the paths appropriate to your own environment.

Background: PEM is the most portable way to share a public key — the Base64 text block most tooling reads. The boolean picks the encoding: false produces the modern, algorithm-independent PUBLIC KEY (SubjectPublicKeyInfo), which is the usual choice; true produces the older RSA-specific RSA PUBLIC KEY for tools that require it. A public key is not sensitive, so the PEM can be distributed openly.

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Lua

local chilkat = require("chilkat")

-- Load a public key to export.  LoadFromFile inspects the content, so it accepts DER, PEM, XML,
-- JWK, and other supported representations.
local pubKey = chilkat.PublicKey.new()
local success = pubKey:load_from_file("qa_data/public.pem")
if not success then
    print(pubKey.last_error_text)
    return
end

-- Export the public key in PEM format.  The argument selects the underlying DER representation:
-- true prefers the traditional PKCS #1 form (RSA), false uses the SubjectPublicKeyInfo form.
local preferPkcs1 = false
local pem = pubKey:get_pem(preferPkcs1)
if not pubKey.last_method_success then
    print(pubKey.last_error_text)
    return
end

print(pem)