Implement basic crypto

.gitignore

@@ -4,3 +4,4 @@
 /venv
 __javascript__
 __pycache__
+refs

build_js.sh

@@ -28,11 +28,11 @@ for f in eos.js_tests; do
 	perl -0777 -pi -e "s/__pragma__ \('.*?'\)//gs" eos/__javascript__/$f.js
 	
 	# Transcrypt by default suppresses stack traces for some reason??
-	perl -0777 -pi -e "s/__except0__.__cause__ = null;//g" eos/__javascript__/$f.js
+	perl -0777 -pi -e 's/__except0__.__cause__ = null;//g' eos/__javascript__/$f.js
 	
 	# Disable handling of special attributes
-	perl -0777 -pi -e "s/var __specialattrib__ = function \(attrib\) \{/var __specialattrib__ = function (attrib) { return false;/g" eos/__javascript__/$f.js
+	perl -0777 -pi -e 's/var __specialattrib__ = function \(attrib\) \{/var __specialattrib__ = function (attrib) { return false;/g' eos/__javascript__/$f.js
 	
 	# Transcrypt bug
-	perl -0777 -pi -e "s/EosObject.EosObject/EosObject/g" eos/__javascript__/$f.js
+	perl -0777 -pi -e 's/property.call \((.*?), \g1.\g1.__impl__(.*?)\)/property.call ($1, $1.__impl__$2)/g' eos/__javascript__/$f.js
 done

eos/core/bigint/js.py

@@ -16,6 +16,8 @@
 
 from eos.core.objects import EosObject
 
+import random
+
 # Load jsbn{,2}.js
 lib = __pragma__('js', '''
 (function() {{
@@ -34,6 +36,8 @@ lib = __pragma__('js', '''
 
 class BigInt(EosObject):
 	def __init__(self, a, b=10):
+		super().__init__()
+		
 		if isinstance(a, str):
 			self.impl = lib.nbi()
 			self.impl.fromString(a, b)
@@ -94,6 +98,41 @@ class BigInt(EosObject):
 			modulo = BigInt(modulo)
 		return BigInt(self.impl.modPow(other.impl, modulo.impl))
 	
+	def serialise(self):
+		return str(self)
+	
+	@classmethod
+	def deserialise(cls, value):
+		return cls(value)
+	
+	# Returns a random BigInt from lower_bound to upper_bound, both inclusive
+	@classmethod
+	def noncrypto_random(cls, lower_bound, upper_bound):
+		if not isinstance(lower_bound, cls):
+			lower_bound = cls(lower_bound)
+		if not isinstance(upper_bound, cls):
+			upper_bound = cls(upper_bound)
+		
+		bound_range = upper_bound - lower_bound + 1
+		bound_range_bits = bound_range.impl.bitLength()
+		
+		# Generate a sufficiently large number; work 32 bits at a time
+		current_range = 0 # bits
+		max_int = 2 ** 32 - 1
+		big_number = cls(0)
+		while current_range < bound_range_bits:
+			random_number = cls(random.randint(0, max_int))
+			big_number = (big_number << 32) | random_number
+			current_range = current_range + 32
+		
+		# Since this is the non-crypto version, just do it modulo
+		return lower_bound + (big_number % bound_range)
+	
+	@classmethod
+	def crypto_random(cls, lower_bound, upper_bound):
+		# TODO
+		return cls.noncrypto_random(lower_bound, upper_bound)
+
 # TNYI: No native pow() support
 def pow(a, b, c=None):
 	if not isinstance(a, BigInt):

eos/core/bigint/python.py

@@ -16,8 +16,13 @@
 
 from eos.core.objects import EosObject
 
+import random
+system_random = random.SystemRandom()
+
 class BigInt(EosObject):
 	def __init__(self, a, b=10):
+		super().__init__()
+		
 		self.impl = int(a, b) if isinstance(a, str) else int(a)
 	
 	def __pow__(self, other, modulo=None):
@@ -29,11 +34,23 @@ class BigInt(EosObject):
 			modulo = BigInt(modulo)
 		return BigInt(self.impl.__pow__(other.impl, modulo.impl))
 	
-for func in [
-	'__add__', '__sub__', '__mul__', '__mod__', '__or__', '__lshift__', '__xor__',
-	'__eq__', '__ne__', '__lt__', '__gt__', '__le__', '__ge__',
-	'__str__'
-]:
+	def serialise(self):
+		return str(self)
+	
+	@classmethod
+	def deserialise(cls, value):
+		return cls(value)
+	
+	# Returns a random BigInt from lower_bound to upper_bound, both inclusive
+	@classmethod
+	def noncrypto_random(cls, lower_bound, upper_bound):
+		return cls(random.randint(int(lower_bound), int(upper_bound)))
+	
+	@classmethod
+	def crypto_random(cls, lower_bound, upper_bound):
+		return cls(system_random.randint(int(lower_bound), int(upper_bound)))
+
+for func in ['__add__', '__sub__', '__mul__', '__mod__', '__or__', '__lshift__', '__xor__']:
 	def make_operator_func(func_):
 		# Create a closure
 		def operator_func(self, other):
@@ -42,3 +59,21 @@ for func in [
 			return BigInt(getattr(self.impl, func_)(other.impl))
 		return operator_func
 	setattr(BigInt, func, make_operator_func(func))
+
+for func in ['__eq__', '__ne__', '__lt__', '__gt__', '__le__', '__ge__']:
+	def make_operator_func(func_):
+		# Create a closure
+		def operator_func(self, other):
+			if not isinstance(other, BigInt):
+				other = BigInt(other)
+			return getattr(self.impl, func_)(other.impl)
+		return operator_func
+	setattr(BigInt, func, make_operator_func(func))
+
+for func in ['__str__', '__int__']:
+	def make_operator_func(func_):
+		# Create a closure
+		def operator_func(self):
+			return getattr(self.impl, func_)()
+		return operator_func
+	setattr(BigInt, func, make_operator_func(func))

eos/core/tests.py

@@ -38,6 +38,10 @@ class EosTestCase:
 					raise Error('Assertion failed: ' + str(a) + ' != ' + str(b))
 	
 	def assertEqualJSON(self, a, b):
+		if isinstance(a, EosObject):
+			a = EosObject.serialise_and_wrap(a)
+		if isinstance(b, EosObject):
+			b = EosObject.serialise_and_wrap(b)
 		self.assertEqual(EosObject.to_json(a), EosObject.to_json(b))
 
 def py_only(func):

eos/js_tests.py

@@ -18,3 +18,4 @@ import eos.js
 
 import eos.core.tests
 import eos.base.tests
+import eos.psgjjr.tests

eos/psgjjr/crypto.py

@@ -0,0 +1,84 @@
+#   Eos - Verifiable elections
+#   Copyright © 2017  RunasSudo (Yingtong Li)
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from eos.core.bigint import *
+from eos.core.objects import *
+
+class CyclicGroup(EmbeddedObject):
+	p = EmbeddedObjectField(BigInt)
+	g = EmbeddedObjectField(BigInt)
+	
+	@property
+	def q(self):
+		# p = 2q + 1
+		return (self.p - ONE) // TWO
+	
+	def random_element(self, crypto_random=True):
+		crypto_method = BigInt.crypto_random if crypto_random else BigInt.noncrypto_random
+		return crypto_method(ONE, self.p - ONE)
+
+# RFC 3526
+DEFAULT_GROUP = CyclicGroup(
+	p=BigInt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
+	g=TWO
+)
+
+class EGPublicKey(EmbeddedObject):
+	group = EmbeddedObjectField(CyclicGroup)
+	X = EmbeddedObjectField(BigInt)
+	
+	# HAC 8.18
+	def encrypt(self, message):
+		# Choose an element 1 <= k <= p - 2
+		k = BigInt.crypto_random(ONE, self.group.p - TWO)
+		
+		gamma = pow(self.group.g, k, self.group.p)
+		delta = (message * pow(self.X, k, self.group.p)) % self.group.p
+		
+		return EGCiphertext(public_key=self, gamma=gamma, delta=delta)
+
+class EGPrivateKey(EmbeddedObject):
+	public_key = EmbeddedObjectField(EGPublicKey)
+	x = EmbeddedObjectField(BigInt)
+	
+	# HAC 8.17
+	@staticmethod
+	def generate():
+		# Choose an element 1 <= x <= p - 2
+		x = BigInt.crypto_random(ONE, DEFAULT_GROUP.p - TWO)
+		# Calculate the public key as G^x
+		X = pow(DEFAULT_GROUP.g, x, DEFAULT_GROUP.p)
+		
+		pk = EGPublicKey(group=DEFAULT_GROUP, X=X)
+		sk = EGPrivateKey(public_key=pk, x=x)
+		return sk
+	
+	# HAC 8.18
+	def decrypt(self, ciphertext):
+		if (
+			ciphertext.gamma <= ZERO or ciphertext.gamma >= self.public_key.group.p or
+			ciphertext.delta <= ZERO or ciphertext.delta >= self.public_key.group.p
+			):
+			raise Exception('Ciphertext is malformed')
+		
+		gamma_inv = pow(ciphertext.gamma, self.public_key.group.p - ONE - self.x, self.public_key.group.p)
+		
+		return (gamma_inv * ciphertext.delta) % self.public_key.group.p
+
+class EGCiphertext(EmbeddedObject):
+	public_key = EmbeddedObjectField(EGPublicKey)
+	gamma = EmbeddedObjectField(BigInt) # G^k
+	delta = EmbeddedObjectField(BigInt) # M X^k

eos/psgjjr/tests.py

@@ -0,0 +1,28 @@
+#   Eos - Verifiable elections
+#   Copyright © 2017  RunasSudo (Yingtong Li)
+#
+#   This program is free software: you can redistribute it and/or modify
+#   it under the terms of the GNU Affero General Public License as published by
+#   the Free Software Foundation, either version 3 of the License, or
+#   (at your option) any later version.
+#
+#   This program is distributed in the hope that it will be useful,
+#   but WITHOUT ANY WARRANTY; without even the implied warranty of
+#   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+#   GNU Affero General Public License for more details.
+#
+#   You should have received a copy of the GNU Affero General Public License
+#   along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+from eos.core.tests import *
+
+from eos.core.bigint import *
+from eos.psgjjr.crypto import *
+
+class EGTestCase(EosTestCase):
+	def test_eg(self):
+		pt = BigInt.noncrypto_random(ONE, DEFAULT_GROUP.p - ONE)
+		sk = EGPrivateKey.generate()
+		ct = sk.public_key.encrypt(pt)
+		m = sk.decrypt(ct)
+		self.assertEqualJSON(pt, m)