Kotlin SDK

The Kotlin account client is in kotlin/MesgdAuth.kt in mesgd-sdk. Use it to enroll an account, obtain a session, and manage public keys independently of the PKI layer. The examples use an existing account named alice; passwords and authenticator codes come from the application rather than literals in source.

Support status

The account adapter is available, but a built-in HTTPS transport is still pending. The transport argument in the examples is application code, not a missing SDK constructor.

Completeness position: 11 of 18. Local JWK/PKI tests; HTTPS transport, shared protocol coverage, and a WSS sample remain pending. The language matrix explains the ranking criteria and comparable tiers. WSS readiness is listed separately; no SDK currently provides a complete, validated encrypted messaging workflow against this server.

Setup and transport

Compile MesgdAuth.kt with java/lib/json.jar on the classpath. The client uses the JVM org.json types. Its functions are synchronous; place network calls on an appropriate worker in applications with a UI.

The constructor accepts (String, String, JSONObject?, String?) -> Pair<Int, JSONObject>. Supply the HTTPS method, relative path, optional body, and optional bearer to your HTTP stack, then return the status and decoded JSON object. No native HTTPS transport is included.

A custom transport must serialize JSON, attach Authorization: Bearer TOKEN only when a token is supplied, verify the certificate and hostname, reject redirects, and use a finite timeout. Its origin is an HTTPS URL, such as https://mesgd.example.com, rather than a WebSocket URL.

Log in, read keys, and log out

Pass the current authenticator code as a six-digit string, preserving leading zeroes. This example reads the account's published keys and ends the session on its successful path. Applications that retain a session can keep the bearer until logout or expiry instead.

import org.json.JSONObject

fun readKeys(
    transport: (String, String, JSONObject?, String?) -> Pair<Int, JSONObject>,
    password: String,
    otp: String
): JSONObject {
    val client = MesgdAuth(transport)
    val session = client.login("alice", password, otp)
    val token = session.getString("access_token")
    return try {
        client.keys(token)
    } finally {
        client.logout(token)
    }
}

Results are JSONObject values. HTTP failures throw MesgdAuth.AuthException with status; invalid OTPs or public keys fail require checks. The repository's Kotlin Makefile contains machine-specific tool paths; override JAVA and KOTLINC for your installation.

Enroll a new account

The following fragment uses an existing client or transport from the example above. Signup returns a pending enrollment. Display qr_png_base64 or otpauth_uri, let the person configure the authenticator, then collect a code to confirm it. These calls are separate application steps, with user interaction between them.

val enrollment = client.signup("alice", "alice@example.com", password)
// Display enrollment before collecting enrollmentOtp.
val session = client.confirm("alice", enrollment.getString("enrollment_token"), enrollmentOtp)
val recoveryCodes = session.getJSONArray("recovery_codes")

Confirmation returns the first session and eight recovery codes. Display the recovery codes for separate safekeeping. A code accepted for confirmation cannot be reused for login or a key update; wait for a new authenticator step before another operation that consumes a code.

Account operations

A key update takes the session token, current password, a fresh authenticator code, and an array containing only public JWKs. An empty array clears the linked keys. A password reset takes the username, a saved recovery code, a new password, and a fresh authenticator code; success replaces the recovery codes and revokes existing sessions without returning a new session.

The shared authentication reference documents argument order, response fields, and transport behavior. Session refresh is available through the HTTP API but is not wrapped by these seven SDK operations.

Local signing and encryption

This example exercises the local PKI implementation without opening a network connection. It signs a short message, verifies it with the same identity, and encrypts and decrypts it locally. It demonstrates the primitives rather than a complete peer-to-peer exchange.

PKI.init("pki_keys.json")
val signature = PKI.sign("hello")
check(PKI.verify("hello", signature))
val ciphertext = PKI.encrypt("hello")
check(PKI.decrypt(ciphertext) == "hello")

For a different recipient, use that recipient's public encryption key rather than the local identity's encryption key. Public-key export and interoperability coverage vary by implementation; see Keys and Languages. Private key files are not account credentials and must not be sent to PUT /auth/keys.

Message connections

There is no Kotlin ping/pong directory in the current samples collection. WSS message-client support remains pending; the JVM can provide a transport as application code.

Account login does not establish a message connection. The current server accepts JSON WebSocket frames and can authenticate an upgrade with a login session or an issued grant token. Login sessions carry identity without path restrictions; grants limit routing to assigned patterns. See WebSocket and Routing.

The encrypted registration handshake in the ping/pong samples is not implemented by the current mesgd listener. Treat those samples as experimental cryptographic examples, with compatibility limits described in Samples.

Validation

This account module is not included in the shared auth contract runner. Check it with the application's own toolchain and transport before deployment. The presence of source examples does not imply that live HTTPS or cross-language cryptographic behavior has been validated for this implementation. Languages lists the repository's current test coverage.