feat: Add Nostr app

pyproject.toml

@@ -32,6 +32,7 @@ click = "~8.1.3"
 base58 = "~2.1.1"
 build = "~1.2.1"
 ecdsa = "~0.19.0"
+bech32 = "^1.2.0"
 
 [tool.poetry.group.dev.dependencies]
 black = "~24.4.2"

src/bipsea/apps/__init__.py

@@ -8,6 +8,7 @@
 from bipsea.apps.dice.app import app as dice_app
 from bipsea.apps.hex.app import app as hex_app
 from bipsea.apps.mnemonic.app import app as mnemonic_app
+from bipsea.apps.nostr.app import app as nostr_app
 from bipsea.apps.wif.app import app as wif_app
 from bipsea.apps.xprv.app import app as xprv_app
 
@@ -17,6 +18,7 @@
     dice_app.name: dice_app,
     hex_app.name: hex_app,
     mnemonic_app.name: mnemonic_app,
+    nostr_app.name: nostr_app,
     wif_app.name: wif_app,
     xprv_app.name: xprv_app,
 }

src/bipsea/apps/nostr/app.py

@@ -0,0 +1,71 @@
+from typing import Any
+
+from bech32 import bech32_encode, convertbits
+
+from bipsea.app_protocol import Param, TestVector
+from bipsea.apps.shared import hardened_int
+
+
+def nsec_encode(key_bytes: bytes) -> str:
+    data = convertbits(key_bytes, 8, 5)
+    return bech32_encode("nsec", data)
+
+
+class NostrApp:
+    name = "nostr"
+    code = "9000'"
+
+    @property
+    def params(self) -> list[Param]:
+        return [
+            Param(
+                "identity",
+                ("--identity",),
+                int,
+                required=True,
+                range=(0, None),
+                help="Identity index (0=proof/revocation key, >=1 usable).",
+            ),
+        ]
+
+    def path_segments(self, index: int, identity: int, **_) -> list[str]:
+        return [f"{identity}'", f"{index}'"]
+
+    def parse_path(self, segments: list[str]) -> dict[str, Any]:
+        return {
+            "identity": hardened_int(segments[0]),
+            "index": hardened_int(segments[1]),
+        }
+
+    def apply(self, entropy: bytes, **_) -> dict[str, Any]:
+        key = entropy[:32]
+        return {
+            "entropy": key,
+            "application": nsec_encode(key),
+        }
+
+    @property
+    def vectors(self) -> list[TestVector]:
+        return [
+            TestVector(
+                master="xprv9s21ZrQH143K2LBWUUQRFXhucrQqBpKdRRxNVq2zBqsx8HVqFk2uYo8kmbaLLHRdqtQpUm98uKfu3vca1LqdGhUtyoFnCNkfmXRyPXLjbKb",
+                path="m/83696968'/9000'/1'/1'",
+                entropy="552ad1d578fe1bc927cec9612651652b07c52dde4017911bc23bc953568075ff",
+                output="nsec1254dr4tclcdujf7we9sjv5t99vru2tw7gqtezx7z80y4x45qwhlsmxapst",
+            ),
+            TestVector(
+                master="xprv9s21ZrQH143K2LBWUUQRFXhucrQqBpKdRRxNVq2zBqsx8HVqFk2uYo8kmbaLLHRdqtQpUm98uKfu3vca1LqdGhUtyoFnCNkfmXRyPXLjbKb",
+                path="m/83696968'/9000'/1'/2'",
+                entropy="4fd36c0061a65db375b4350f44bb62a6d7f716ee93bd0f59887ac50b35fa8b96",
+                output="nsec1flfkcqrp5ewmxad5x585fwmz5mtlw9hwjw7s7kvg0tzskd063wtq34wlgr",
+            ),
+            TestVector(
+                master="xprv9s21ZrQH143K2LBWUUQRFXhucrQqBpKdRRxNVq2zBqsx8HVqFk2uYo8kmbaLLHRdqtQpUm98uKfu3vca1LqdGhUtyoFnCNkfmXRyPXLjbKb",
+                path="m/83696968'/9000'/2'/1'",
+                entropy="b2d3b48992d46f98beac0196c4e258417087e467dbec1503342785368f4402c2",
+                output="nsec1ktfmfzvj63he304vqxtvfcjcg9cg0er8m0kp2qe5y7zndr6yqtpq7q5y44",
+            ),
+        ]
+
+
+app = NostrApp()

src/bipsea/bipsea.py

@@ -205,7 +205,13 @@ def xprv(mnemonic, passphrase, mainnet):
     type=click.Choice(ENTROPY_TO_VALUES),
     help="Output language for `--application mnemonic`.",
 )
-def derive_cli(application, number, index, special, xprv, to):
+@click.option(
+    "--identity",
+    type=click.IntRange(0, 2**31 - 1),
+    default=None,
+    help="Nostr identity index (0=proof/revocation key, >=1 usable). Required for --application nostr.",
+)
+def derive_cli(application, number, index, special, xprv, to, identity):
     if xprv:
         xprv = xprv.strip()
     else:
@@ -253,6 +259,24 @@ def derive_cli(application, number, index, special, xprv, to):
     elif application == "dice":
         check_range(number, application)
         path += f"/{special}'/{number}'/{index}'"
+    elif application == "nostr":
+        if identity is None:
+            raise click.UsageError(
+                "--identity is required for --application nostr."
+            )
+        if identity == 0:
+            click.secho(
+                "Warning: identity=0 is reserved as a proof key to link identities together.",
+                fg="yellow",
+                err=True,
+            )
+        if index == 0:
+            click.secho(
+                f"Warning: index=0 is reserved as the proof key to link accounts for identity {identity}.",
+                fg="yellow",
+                err=True,
+            )
+        path += f"/{identity}'/{index}'"
 
     derived = derive(master, path)
     if application == "drng":

tests/test_cli.py

@@ -18,6 +18,7 @@
 from bipsea.apps.dice.app import app as dice_app
 from bipsea.apps.hex.app import app as hex_app
 from bipsea.apps.mnemonic.app import app as mnemonic_app
+from bipsea.apps.nostr.app import app as nostr_app
 from bipsea.apps.wif.app import app as wif_app
 from bipsea.bip32types import validate_prv_str
 from bipsea.bip39 import LANGUAGES, validate_mnemonic_words
@@ -449,6 +450,60 @@ def test_commands(self, group, commands):
             Path(script.name).unlink()
 
 
+class TestNostr:
+    def test_path_segments(self):
+        assert nostr_app.path_segments(index=2, identity=1) == ["1'", "2'"]
+
+    @pytest.mark.parametrize("vector", nostr_app.vectors)
+    def test_vectors(self, runner, vector):
+        segments = vector.path.split("/")
+        identity = int(segments[3].rstrip("'"))
+        index = int(segments[4].rstrip("'"))
+        result = runner.invoke(
+            cli,
+            [
+                "derive",
+                "-a", "nostr",
+                "-x", vector.master,
+                "--identity", identity,
+                "--index", index,
+            ],
+        )
+        assert result.exit_code == 0
+        assert result.output.strip() == vector.output
+
+    def test_missing_identity(self, runner):
+        result = runner.invoke(
+            cli, ["derive", "-a", "nostr", "-x", nostr_app.vectors[0].master]
+        )
+        assert result.exit_code != 0
+        assert "identity" in result.output
+
+    def test_identity_zero_warning(self, runner):
+        result = runner.invoke(
+            cli,
+            [
+                "derive", "-a", "nostr",
+                "-x", nostr_app.vectors[0].master,
+                "--identity", 0,
+                "--index", 1,
+            ],
+        )
+        assert "Warning" in result.output
+
+    def test_index_zero_warning(self, runner):
+        result = runner.invoke(
+            cli,
+            [
+                "derive", "-a", "nostr",
+                "-x", nostr_app.vectors[0].master,
+                "--identity", 1,
+                "--index", 0,
+            ],
+        )
+        assert "Warning" in result.output
+
+
 class TestCliAdapter:
     def test_required_param(self):
         param = Param("length", ("-n", "--length"), int, required=True, help="Length")