From 4cfcfb4ff458aa4fcb48679b47e1b5b2dc570365 Mon Sep 17 00:00:00 2001
From: Tomas Susanka <tsusanka@gmail.com>
Date: Fri, 11 May 2018 15:31:53 +0200
Subject: [PATCH] stellar: init; get public key

---
 src/apps/common/seed.py            |  5 ++
 src/apps/stellar/README.md         | 11 +++++
 src/apps/stellar/__init__.py       | 11 +++++
 src/apps/stellar/get_public_key.py | 74 ++++++++++++++++++++++++++++++
 src/main.py                        |  2 +
 5 files changed, 103 insertions(+)
 create mode 100644 src/apps/stellar/README.md
 create mode 100644 src/apps/stellar/__init__.py
 create mode 100644 src/apps/stellar/get_public_key.py

diff --git a/src/apps/common/seed.py b/src/apps/common/seed.py
index 1bb22f5937..aba0a23d69 100644
--- a/src/apps/common/seed.py
+++ b/src/apps/common/seed.py
@@ -43,3 +43,8 @@ def derive_node_without_passphrase(
     node = bip32.from_seed(seed, curve_name)
     node.derive_path(path)
     return node
+
+
+def remove_ed25519_public_key_prefix(pubkey: bytes) -> bytes:
+    # 0x01 prefix is not part of the actual public key, hence removed
+    return pubkey[1:]
diff --git a/src/apps/stellar/README.md b/src/apps/stellar/README.md
new file mode 100644
index 0000000000..717b1d4b13
--- /dev/null
+++ b/src/apps/stellar/README.md
@@ -0,0 +1,11 @@
+# Stellar
+
+MAINTAINER = Tomas Susanka <tomas.susanka@satoshilabs.com>
+
+AUTHOR = Tomas Susanka <tomas.susanka@satoshilabs.com>
+
+REVIEWER = Jan Pochyla <jan.pochyla@satoshilabs.com>
+
+-----
+
+TODO
diff --git a/src/apps/stellar/__init__.py b/src/apps/stellar/__init__.py
new file mode 100644
index 0000000000..eb8ca62500
--- /dev/null
+++ b/src/apps/stellar/__init__.py
@@ -0,0 +1,11 @@
+from trezor.wire import register, protobuf_workflow
+from trezor.messages.wire_types import StellarGetPublicKey
+
+
+def dispatch_StellarGetPublicKey(*args, **kwargs):
+    from .get_public_key import get_public_key
+    return get_public_key(*args, **kwargs)
+
+
+def boot():
+    register(StellarGetPublicKey, protobuf_workflow, dispatch_StellarGetPublicKey)
diff --git a/src/apps/stellar/get_public_key.py b/src/apps/stellar/get_public_key.py
new file mode 100644
index 0000000000..4ced0caa70
--- /dev/null
+++ b/src/apps/stellar/get_public_key.py
@@ -0,0 +1,74 @@
+from apps.common import seed
+from apps.common.confirm import confirm
+from trezor import ui
+from trezor.messages.StellarPublicKey import StellarPublicKey
+from trezor.messages.StellarGetPublicKey import StellarGetPublicKey
+from trezor.messages import ButtonRequestType
+from trezor.ui.text import Text
+from trezor.utils import chunks
+from trezor.crypto import base32
+import ustruct
+
+STELLAR_CURVE = 'ed25519'
+
+
+async def get_public_key(ctx, msg: StellarGetPublicKey):
+    node = await seed.derive_node(ctx, msg.address_n, STELLAR_CURVE)
+    pubkey = seed.remove_ed25519_public_key_prefix(node.public_key())  # todo better?
+
+    while True:
+        if await _show(ctx, _address_from_public_key(pubkey)):
+            break
+
+    return StellarPublicKey(public_key=pubkey)
+
+
+async def _show(ctx, address: str):
+    lines = _split_address(address)
+    content = Text('Export Stellar ID', ui.ICON_RECEIVE,
+                   ui.NORMAL, 'Share public account ID?',
+                   ui.MONO, *lines,
+                   icon_color=ui.GREEN)
+
+    return await confirm(
+        ctx,
+        content,
+        code=ButtonRequestType.Address,
+        cancel_style=ui.BTN_KEY)
+
+
+def _split_address(address: str):
+    return chunks(address, 17)
+
+
+def _address_from_public_key(pubkey: bytes):
+    """Returns the base32-encoded version of public key bytes (G...)"""
+
+    address = bytearray()
+    address.append(6 << 3)  # version -> 'G'
+    address.extend(pubkey)
+    address.extend(ustruct.pack("<H", _crc16_checksum(address)))  # checksum
+
+    print(base32.encode(address))
+    return base32.encode(address)
+
+
+def _crc16_checksum(data: bytearray):
+    """Returns the CRC-16 checksum of bytearray bytes
+
+    Ported from Java implementation at: http://introcs.cs.princeton.edu/java/61data/CRC16CCITT.java.html
+
+    Initial value changed to 0x0000 to match Stellar configuration.
+    """
+    crc = 0x0000
+    polynomial = 0x1021
+
+    for byte in data:
+        for i in range(8):
+            bit = ((byte >> (7 - i) & 1) == 1)
+            c15 = ((crc >> 15 & 1) == 1)
+            crc <<= 1
+            if c15 ^ bit:
+                crc ^= polynomial
+
+    return crc & 0xffff
diff --git a/src/main.py b/src/main.py
index 8b61f99674..ce5f72abe9 100644
--- a/src/main.py
+++ b/src/main.py
@@ -15,6 +15,7 @@ import apps.wallet
 import apps.ethereum
 import apps.lisk
 import apps.nem
+import apps.stellar
 
 if __debug__:
     import apps.debug
@@ -28,6 +29,7 @@ apps.wallet.boot()
 apps.ethereum.boot()
 apps.lisk.boot()
 apps.nem.boot()
+apps.stellar.boot()
 if __debug__:
     apps.debug.boot()
 else: