5 files changed, 118 insertions, 1 deletions

diff --git a/Makefile b/Makefile
index 547797d..1ae4371 100644
--- a/Makefile
+++ b/Makefile
@@ -4,7 +4,7 @@ ec.test_mult ec.test_naf ec.test_op ec.test_point ec.test_signature ec.test_tran
 
 SCA_TESTS = sca.test_align sca.test_combine sca.test_edit sca.test_filter sca.test_match sca.test_process \
 sca.test_sampling sca.test_target sca.test_test sca.test_trace sca.test_traceset sca.test_plot sca.test_rpa \
-sca.test_stacked_combine
+sca.test_stacked_combine sca.test_leakage_models
 
 TESTS = ${EC_TESTS} ${SCA_TESTS}
 
diff --git a/pyecsca/sca/__init__.py b/pyecsca/sca/__init__.py
index 5b359b8..89e8527 100644
--- a/pyecsca/sca/__init__.py
+++ b/pyecsca/sca/__init__.py
@@ -6,3 +6,4 @@ from .target import *
 from .trace import *
 from .trace_set import *
 from .stacked_traces import *
+from .attack import *
diff --git a/pyecsca/sca/attack/__init__.py b/pyecsca/sca/attack/__init__.py
new file mode 100644
index 0000000..23e27cb
--- /dev/null
+++ b/pyecsca/sca/attack/__init__.py
@@ -0,0 +1 @@
+from .leakage_model import *
diff --git a/pyecsca/sca/attack/leakage_model.py b/pyecsca/sca/attack/leakage_model.py
new file mode 100644
index 0000000..8fdb2ca
--- /dev/null
+++ b/pyecsca/sca/attack/leakage_model.py
@@ -0,0 +1,67 @@
+import abc
+from typing import Literal, ClassVar
+
+
+class LeakageModel(abc.ABC):
+    num_args: ClassVar[int]
+
+    @abc.abstractmethod
+    def __call__(self, *args, **kwargs) -> int:
+        raise NotImplementedError
+
+
+class Identity(LeakageModel):
+    num_args = 1
+
+    def __call__(self, *args, **kwargs) -> int:
+        return int(args[0])
+
+
+class Bit(LeakageModel):
+    num_args = 1
+
+    def __init__(self, which: int):
+        if which < 0:
+            raise ValueError("which must be >= 0.")
+        self.which = which
+        self.mask = 1 << which
+
+    def __call__(self, *args, **kwargs) -> Literal[0, 1]:
+        return (int(args[0]) & self.mask) >> self.which  # type: ignore
+
+
+class Slice(LeakageModel):
+    num_args = 1
+
+    def __init__(self, begin: int, end: int):
+        if begin > end:
+            raise ValueError("begin must be <= than end.")
+        self.begin = begin
+        self.end = end
+        self.mask = 0
+        for i in range(begin, end):
+            self.mask |= 1 << i
+
+    def __call__(self, *args, **kwargs) -> int:
+        return (int(args[0]) & self.mask) >> self.begin
+
+
+class HammingWeight(LeakageModel):
+    num_args = 1
+
+    def __call__(self, *args, **kwargs) -> int:
+        return int(args[0]).bit_count()
+
+
+class HammingDistance(LeakageModel):
+    num_args = 2
+
+    def __call__(self, *args, **kwargs) -> int:
+        return (int(args[0]) ^ int(args[1])).bit_count()
+
+
+class BitLength(LeakageModel):
+    num_args = 1
+
+    def __call__(self, *args, **kwargs) -> int:
+        return int(args[0]).bit_length()
diff --git a/test/sca/test_leakage_models.py b/test/sca/test_leakage_models.py
new file mode 100644
index 0000000..f951083
--- /dev/null
+++ b/test/sca/test_leakage_models.py
@@ -0,0 +1,48 @@
+from unittest import TestCase
+
+from pyecsca.ec.mod import Mod
+from pyecsca.sca.attack.leakage_model import Identity, Bit, Slice, HammingWeight, HammingDistance, BitLength
+
+
+class LeakageModelTests(TestCase):
+
+    def test_identity(self):
+        val = Mod(3, 7)
+        lm = Identity()
+        self.assertEqual(lm(val), 3)
+
+    def test_bit(self):
+        val = Mod(3, 7)
+        lm = Bit(0)
+        self.assertEqual(lm(val), 1)
+        lm = Bit(4)
+        self.assertEqual(lm(val), 0)
+        with self.assertRaises(ValueError):
+            Bit(-3)
+
+    def test_slice(self):
+        val = Mod(0b11110000, 0xf00)
+        lm = Slice(0, 4)
+        self.assertEqual(lm(val), 0)
+        lm = Slice(1, 5)
+        self.assertEqual(lm(val), 0b1000)
+        lm = Slice(4, 8)
+        self.assertEqual(lm(val), 0b1111)
+        with self.assertRaises(ValueError):
+            Slice(7, 1)
+
+    def test_hamming_weight(self):
+        val = Mod(0b11110000, 0xf00)
+        lm = HammingWeight()
+        self.assertEqual(lm(val), 4)
+
+    def test_hamming_distance(self):
+        a = Mod(0b11110000, 0xf00)
+        b = Mod(0b00010000, 0xf00)
+        lm = HammingDistance()
+        self.assertEqual(lm(a, b), 3)
+
+    def test_bit_length(self):
+        a = Mod(0b11110000, 0xf00)
+        lm = BitLength()
+        self.assertEqual(lm(a), 8)