1 files changed, 91 insertions, 0 deletions
diff --git a/pyecsca/codegen/client.py b/pyecsca/codegen/client.py
new file mode 100644
index 0000000..9d839fb
--- /dev/null
+++ b/pyecsca/codegen/client.py
@@ -0,0 +1,91 @@
+#!/usr/bin/env python3
+from binascii import hexlify
+from typing import Mapping, Union, Optional
+
+import click
+from pyecsca.ec.coordinates import AffineCoordinateModel
+from pyecsca.ec.curve import EllipticCurve
+from pyecsca.ec.group import AbelianGroup
+from pyecsca.ec.mod import Mod
+from pyecsca.ec.model import ShortWeierstrassModel
+from pyecsca.ec.point import Point
+
+
+def encode_scalar(val: Union[int, Mod]) -> bytes:
+    if isinstance(val, int):
+        return val.to_bytes((val.bit_length() + 7) // 8, "big")
+    elif isinstance(val, Mod):
+        return encode_scalar(val.x)
+
+
+def encode_point(point: Point) -> Mapping:
+    return {var: encode_scalar(value) for var, value in point.coords.items()}
+
+
+def encode_data(name: Optional[str], structure: Union[Mapping, bytes]) -> bytes:
+    if isinstance(structure, bytes):
+        header = bytes([ord(name)]) + bytes([len(structure)])
+        return header + structure
+    data = bytes()
+    for k, v in structure.items():
+        data += encode_data(k, v)
+    if name is not None:
+        return bytes([ord(name) | 0x80]) + bytes([len(data)]) + data
+    return data
+
+
+def decode_data(data: bytes) -> Mapping:
+    result = {}
+    parsed = 0
+    while parsed < len(data):
+        name = data[parsed]
+        length = data[parsed + 1]
+        if name & 0x80:
+            sub = decode_data(data[parsed + 2: parsed + 2 + length])
+            result[chr(name | 0x7f)] = sub
+            parsed += len(sub) + 2
+        else:
+            result[chr(name)] = data[parsed + 2: parsed + 2 + length]
+            parsed += length + 2
+    return result
+
+
+def cmd_init_prng(seed: bytes) -> str:
+    return "i" + hexlify(seed).decode()
+
+
+def cmd_set_curve(group: AbelianGroup) -> str:
+    data = {
+        "p": encode_scalar(group.curve.prime),
+        "n": encode_scalar(group.order),
+        "h": encode_scalar(group.cofactor)
+    }
+    for param, value in group.curve.parameters.items():
+        data[param] = encode_scalar(value)
+    data["g"] = encode_point(group.generator)
+    data["i"] = encode_point(group.neutral)
+    return "c" + hexlify(encode_data(None, data)).decode()
+
+
+@click.command()
+@click.version_option()
+def main():
+    model = ShortWeierstrassModel()
+    coords = model.coordinates["projective"]
+    p = 0xffffffff00000001000000000000000000000000ffffffffffffffffffffffff
+    curve = EllipticCurve(model, coords,
+                          p,
+                          {"a": 0xffffffff00000001000000000000000000000000fffffffffffffffffffffffc,
+                           "b": 0x5ac635d8aa3a93e7b3ebbd55769886bc651d06b0cc53b0f63bce3c3e27d2604b})
+    affine_g = Point(AffineCoordinateModel(model),
+                     x=Mod(0x6b17d1f2e12c4247f8bce6e563a440f277037d812deb33a0f4a13945d898c296, p),
+                     y=Mod(0x4fe342e2fe1a7f9b8ee7eb4a7c0f9e162bce33576b315ececbb6406837bf51f5, p))
+    g = Point.from_affine(coords, affine_g)
+    neutral = Point(coords, X=Mod(0, p), Y=Mod(1, p), Z=Mod(0, p))
+    group = AbelianGroup(curve, g, neutral,
+                         0xffffffff00000000ffffffffffffffffbce6faada7179e84f3b9cac2fc632551, 0x1)
+    print(cmd_set_curve(group))
+
+
+if __name__ == "__main__":
+    main()