feat(companion): backup envelope + NIP-46 signer crypto in the native core

Extends archy-fips-core with the two companion-release features' crypto (#128, #139), same JNI-over-JSON contract as the mesh surface: backup.rs — the ADR-005 encrypted-backup envelope, byte-compatible with the node's backup code (Argon2id default params + ChaCha20-Poly1305, blob = base64(salt||nonce||ct)); decrypt ignores extra envelope fields so node backups read here too. Round-trip, tamper, wrong-passphrase and cross-shape tests included. nostr.rs — the phone-side remote-signer crypto: nsec/npub bech32 keys, BIP340 schnorr event signing (NIP-01 id serialization), NIP-44 v2 payloads (HKDF-SHA256 + ChaCha20 + HMAC-SHA256, both padding prefixes), NIP-04 fallback, nostrconnect:// parsing with repeated relay params. Verified against the official NIP-44 vectors (conversation keys, message keys, padded lengths, byte-exact encrypt vectors), the BIP-340 reference sign vectors, and round-trip/tamper/failure tests. secp256k1 0.29 note: Keypair::public_key() is the 33-byte compressed key — x-only pubkeys must go through .x_only_public_key().0 (one real bug the vectors caught). JNI glue adds com.archipelago.app.NativeCore: backupEncrypt/Decrypt, nostrGenerateSecret/SecretFromAny/ParseConnectUri/SignEvent and the NIP-44/NIP-04 cipher pairs. Android arm64 build verified via cargo-ndk (7.2 MB .so, +0.4 MB for both modules). Host: cargo test 23/23, clippy clean.
2026-08-31 13:29:36 +01:00
parent 12c853da45
commit 57e31eb192
6 changed files with 1621 additions and 3 deletions
@@ -1,5 +1,6 @@
-//! JNI surface for `com.archipelago.app.fips.FipsNative` — JSON over strings,
-//! no codegen (the myco / nostr-vpn embedding pattern). Errors come back as
+//! JNI surface for `com.archipelago.app.fips.FipsNative` and
+//! `com.archipelago.app.NativeCore` — JSON over strings, no codegen (the
+//! myco / nostr-vpn embedding pattern). Errors come back as
 //! `{"error": "…"}` so Kotlin never sees a raw exception from native code.

 use std::sync::Once;
@@ -127,3 +128,177 @@ pub extern "system" fn Java_com_archipelago_app_fips_FipsNative_statusJson(
 ) -> jstring {
    out(&env, mesh::status_json())
 }
+
+// ─────────────────────────────────────────────────────────────────────────────
+// com.archipelago.app.NativeCore — companion backup (#128) and NIP-46 remote
+// signer crypto (#139). Same library, JSON-over-strings contract.
+// ─────────────────────────────────────────────────────────────────────────────
+
+/// Kotlin: `external fun backupEncrypt(payload: String, passphrase: String): String`
+/// Returns the ADR-005 envelope JSON or `{"error": …}`.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_NativeCore_backupEncrypt(
+    mut env: JNIEnv,
+    _class: JClass,
+    payload: JString,
+    passphrase: JString,
+) -> jstring {
+    init_logging();
+    let payload = jstr(&mut env, &payload);
+    let passphrase = jstr(&mut env, &passphrase);
+    let json = match crate::backup::encrypt(&payload, &passphrase) {
+        Ok(envelope) => envelope,
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun backupDecrypt(envelope: String, passphrase: String): String`
+/// Returns the decrypted payload JSON or `{"error": …}`.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_NativeCore_backupDecrypt(
+    mut env: JNIEnv,
+    _class: JClass,
+    envelope: JString,
+    passphrase: JString,
+) -> jstring {
+    init_logging();
+    let envelope = jstr(&mut env, &envelope);
+    let passphrase = jstr(&mut env, &passphrase);
+    let json = match crate::backup::decrypt(&envelope, &passphrase) {
+        Ok(payload) => payload,
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun nostrGenerateSecret(): String`
+/// Returns `{"secret": hex, "pubkey": hex, "npub": …, "nsec": …}` or `{"error": …}`.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_NativeCore_nostrGenerateSecret(
+    env: JNIEnv,
+    _class: JClass,
+) -> jstring {
+    init_logging();
+    let json = match crate::nostr::generate_secret() {
+        Ok(secret) => nostr_key_info_json(&secret),
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun nostrSecretFromAny(secret: String): String`
+/// Accepts hex or `nsec…`; returns key-info JSON or `{"error": …}`.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_NativeCore_nostrSecretFromAny(
+    mut env: JNIEnv,
+    _class: JClass,
+    secret: JString,
+) -> jstring {
+    init_logging();
+    let secret = jstr(&mut env, &secret);
+    let json = match crate::nostr::secret_from_any(&secret) {
+        Ok(hex) => nostr_key_info_json(&hex),
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+fn nostr_key_info_json(secret_hex: &str) -> String {
+    match (
+        crate::nostr::pubkey_hex(secret_hex),
+        crate::nostr::npub_from_pubkey(&crate::nostr::pubkey_hex(secret_hex).unwrap_or_default()),
+        crate::nostr::nsec_from_secret(secret_hex),
+    ) {
+        (Ok(pubkey), Ok(npub), Ok(nsec)) => serde_json::json!({
+            "secret": secret_hex,
+            "pubkey": pubkey,
+            "npub": npub,
+            "nsec": nsec,
+        })
+        .to_string(),
+        (e, _, _) => err_json(e.unwrap_err()),
+    }
+}
+
+/// Kotlin: `external fun nostrParseConnectUri(uri: String): String`
+/// Returns the parsed URI fields or `{"error": …}`.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_NativeCore_nostrParseConnectUri(
+    mut env: JNIEnv,
+    _class: JClass,
+    uri: JString,
+) -> jstring {
+    init_logging();
+    let uri = jstr(&mut env, &uri);
+    let json = match crate::nostr::parse_connect_uri(&uri) {
+        Ok(info) => info.to_json().to_string(),
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+/// Kotlin: `external fun nostrSignEvent(secretHex: String, eventJson: String): String`
+/// Returns the signed event JSON or `{"error": …}`. The approve/deny decision
+/// is made in Kotlin BEFORE this is called — native code never signs unasked.
+#[no_mangle]
+pub extern "system" fn Java_com_archipelago_app_NativeCore_nostrSignEvent(
+    mut env: JNIEnv,
+    _class: JClass,
+    secret_hex: JString,
+    event_json: JString,
+) -> jstring {
+    init_logging();
+    let secret = jstr(&mut env, &secret_hex);
+    let event = jstr(&mut env, &event_json);
+    let json = match crate::nostr::sign_event(&secret, &event) {
+        Ok(signed) => signed,
+        Err(e) => err_json(e),
+    };
+    out(&env, json)
+}
+
+macro_rules! nostr_cipher {
+    ($name:ident, $doc:literal, $fn:path) => {
+        #[doc = $doc]
+        #[no_mangle]
+        pub extern "system" fn $name(
+            mut env: JNIEnv,
+            _class: JClass,
+            secret_hex: JString,
+            peer_pub: JString,
+            text: JString,
+        ) -> jstring {
+            init_logging();
+            let secret = jstr(&mut env, &secret_hex);
+            let peer = jstr(&mut env, &peer_pub);
+            let text = jstr(&mut env, &text);
+            let json = match $fn(&secret, &peer, &text) {
+                Ok(out) => serde_json::json!({ "result": out }).to_string(),
+                Err(e) => err_json(e),
+            };
+            out(&env, json)
+        }
+    };
+}
+
+nostr_cipher!(
+    Java_com_archipelago_app_NativeCore_nostrNip44Encrypt,
+    "Kotlin: `external fun nostrNip44Encrypt(secretHex: String, peerPub: String, plaintext: String): String` — returns `{\"result\": payload}` or `{\"error\": …}`.",
+    crate::nostr::nip44_encrypt
+);
+nostr_cipher!(
+    Java_com_archipelago_app_NativeCore_nostrNip44Decrypt,
+    "Kotlin: `external fun nostrNip44Decrypt(secretHex: String, peerPub: String, payload: String): String`",
+    crate::nostr::nip44_decrypt
+);
+nostr_cipher!(
+    Java_com_archipelago_app_NativeCore_nostrNip04Encrypt,
+    "Kotlin: `external fun nostrNip04Encrypt(secretHex: String, peerPub: String, plaintext: String): String`",
+    crate::nostr::nip04_encrypt
+);
+nostr_cipher!(
+    Java_com_archipelago_app_NativeCore_nostrNip04Decrypt,
+    "Kotlin: `external fun nostrNip04Decrypt(secretHex: String, peerPub: String, payload: String): String`",
+    crate::nostr::nip04_decrypt
+);