# # SelfTest/PublicKey/test_ElGamal.py: Self-test for the ElGamal primitive # # =================================================================== # The contents of this file are dedicated to the public domain. To # the extent that dedication to the public domain is not available, # everyone is granted a worldwide, perpetual, royalty-free, # non-exclusive license to exercise all rights associated with the # contents of this file for any purpose whatsoever. # No rights are reserved. # # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, # EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF # MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND # NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS # BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN # ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN # CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE # SOFTWARE. # =================================================================== """Self-test suite for Crypto.PublicKey.ElGamal""" __revision__ = "$Id$" import pytest from Crypto import Random from Crypto.PublicKey import ElGamal from Crypto.SelfTest.st_common import a2b_hex from Crypto.Util.number import bytes_to_long class TestElGamal: def test_component_types(self): tv = self.tve[0] p, g, y, x = (int(tv[c], 16) for c in ("p", "g", "y", "x")) key = ElGamal.construct((p, g, y, x)) for value, expected in ((key.p, p), (key.g, g), (key.y, y), (key.x, x)): assert type(value) is int assert value == expected assert key.has_private() pub = key.publickey() assert not pub.has_private() with pytest.raises(AttributeError): _ = pub.x assert pub.p == p # # Test vectors # # There seem to be no real ElGamal test vectors available in the # public domain. The following test vectors have been generated # with libgcrypt 1.5.0. # # Encryption tve = [ { # 256 bits "p": "BA4CAEAAED8CBE952AFD2126C63EB3B345D65C2A0A73D2A3AD4138B6D09BD933", "g": "05", "y": "60D063600ECED7C7C55146020E7A31C4476E9793BEAED420FEC9E77604CAE4EF", "x": "1D391BA2EE3C37FE1BA175A69B2C73A11238AD77675932", "k": "F5893C5BAB4131264066F57AB3D8AD89E391A0B68A68A1", "pt": "48656C6C6F207468657265", "ct1": "32BFD5F487966CEA9E9356715788C491EC515E4ED48B58F0F00971E93AAA5EC7", "ct2": "7BE8FBFF317C93E82FCEF9BD515284BA506603FEA25D01C0CB874A31F315EE68", }, { # 512 bits "p": "F1B18AE9F7B4E08FDA9A04832F4E919D89462FD31BF12F92791A93519F75076D6CE3942689CDFF2F344CAFF0F82D01864F69F3AECF566C774CBACF728B81A227", "g": "07", "y": "688628C676E4F05D630E1BE39D0066178CA7AA83836B645DE5ADD359B4825A12B02EF4252E4E6FA9BEC1DB0BE90F6D7C8629CABB6E531F472B2664868156E20C", "x": "14E60B1BDFD33436C0DA8A22FDC14A2CCDBBED0627CE68", "k": "38DBF14E1F319BDA9BAB33EEEADCAF6B2EA5250577ACE7", "pt": "48656C6C6F207468657265", "ct1": "290F8530C2CC312EC46178724F196F308AD4C523CEABB001FACB0506BFED676083FE0F27AC688B5C749AB3CB8A80CD6F7094DBA421FB19442F5A413E06A9772B", "ct2": "1D69AAAD1DC50493FB1B8E8721D621D683F3BF1321BE21BC4A43E11B40C9D4D9C80DE3AAC2AB60D31782B16B61112E68220889D53C4C3136EE6F6CE61F8A23A0", }, ] # Signature tvs = [ { # 256 bits "p": "D2F3C41EA66530838A704A48FFAC9334F4701ECE3A97CEE4C69DD01AE7129DD7", "g": "05", "y": "C3F9417DC0DAFEA6A05C1D2333B7A95E63B3F4F28CC962254B3256984D1012E7", "x": "165E4A39BE44D5A2D8B1332D416BC559616F536BC735BB", "k": "C7F0C794A7EAD726E25A47FF8928013680E73C51DD3D7D99BFDA8F492585928F", "h": "48656C6C6F207468657265", "sig1": "35CA98133779E2073EF31165AFCDEB764DD54E96ADE851715495F9C635E1E7C2", "sig2": "0135B88B1151279FE5D8078D4FC685EE81177EE9802AB123A73925FC1CB059A7", }, { # 512 bits "p": "E24CF3A4B8A6AF749DCA6D714282FE4AABEEE44A53BB6ED15FBE32B5D3C3EF9CC4124A2ECA331F3C1C1B667ACA3766825217E7B5F9856648D95F05330C6A19CF", "g": "0B", "y": "2AD3A1049CA5D4ED207B2431C79A8719BB4073D4A94E450EA6CEE8A760EB07ADB67C0D52C275EE85D7B52789061EE45F2F37D9B2AE522A51C28329766BFE68AC", "x": "16CBB4F46D9ECCF24FF9F7E63CAA3BD8936341555062AB", "k": "8A3D89A4E429FD2476D7D717251FB79BF900FFE77444E6BB8299DC3F84D0DD57ABAB50732AE158EA52F5B9E7D8813E81FD9F79470AE22F8F1CF9AEC820A78C69", "h": "48656C6C6F207468657265", "sig1": "BE001AABAFFF976EC9016198FBFEA14CBEF96B000CCC0063D3324016F9E91FE80D8F9325812ED24DDB2B4D4CF4430B169880B3CE88313B53255BD4EC0378586F", "sig2": "5E266F3F837BA204E3BBB6DBECC0611429D96F8C7CE8F4EFDF9D4CB681C2A954468A357BF4242CEC7418B51DFC081BCD21299EF5B5A0DDEF3A139A1817503DDE", }, ] def test_generate_180(self): self._test_random_key(180) @pytest.mark.parametrize("tv", tve) def test_encryption(self, tv): d = self.convert_tv(tv, True) key = ElGamal.construct(d["key"]) ct = key._encrypt(d["pt"], d["k"]) assert ct[0] == d["ct1"] assert ct[1] == d["ct2"] @pytest.mark.parametrize("tv", tve) def test_decryption(self, tv): d = self.convert_tv(tv, True) key = ElGamal.construct(d["key"]) pt = key._decrypt((d["ct1"], d["ct2"])) assert pt == d["pt"] @pytest.mark.parametrize("tv", tvs) def test_signing(self, tv): d = self.convert_tv(tv, True) key = ElGamal.construct(d["key"]) sig1, sig2 = key._sign(d["h"], d["k"]) assert sig1 == d["sig1"] assert sig2 == d["sig2"] @pytest.mark.parametrize("tv", tvs) def test_verification(self, tv): d = self.convert_tv(tv, True) key = ElGamal.construct(d["key"]) # Positive test res = key._verify(d["h"], (d["sig1"], d["sig2"])) assert res # Negative test res = key._verify(d["h"], (d["sig1"] + 1, d["sig2"])) assert not res def test_bad_key3(self): tup = tup0 = list(self.convert_tv(self.tvs[0], 1)["key"])[:3] tup[0] += 1 # p += 1 (not prime) with pytest.raises(ValueError): ElGamal.construct(tup) tup = tup0 tup[1] = 1 # g = 1 with pytest.raises(ValueError): ElGamal.construct(tup) tup = tup0 tup[2] = tup[0] * 2 # y = 2*p with pytest.raises(ValueError): ElGamal.construct(tup) def test_bad_key4(self): tup = list(self.convert_tv(self.tvs[0], 1)["key"]) tup[3] += 1 # x += 1 with pytest.raises(ValueError): ElGamal.construct(tup) def convert_tv(self, tv, as_longs=0): """Convert a test vector from textual form (hexadecimal ascii to either integers or byte strings.""" key_comps = "p", "g", "y", "x" tv2 = {} for c in tv: tv2[c] = a2b_hex(tv[c]) if as_longs or c in key_comps or c in ("sig1", "sig2"): tv2[c] = bytes_to_long(tv2[c]) tv2["key"] = [] for c in key_comps: tv2["key"] += [tv2[c]] del tv2[c] return tv2 def _test_random_key(self, bits): elgObj = ElGamal.generate(bits, Random.new().read) self._check_private_key(elgObj) self._exercise_primitive(elgObj) pub = elgObj.publickey() self._check_public_key(pub) self._exercise_public_primitive(elgObj) def _check_private_key(self, elgObj): # Check capabilities assert elgObj.has_private() # Sanity check key data assert 1 < elgObj.g < (elgObj.p - 1) assert pow(elgObj.g, elgObj.p - 1, elgObj.p) == 1 assert 1 < elgObj.x < (elgObj.p - 1) assert pow(elgObj.g, elgObj.x, elgObj.p) == elgObj.y def _check_public_key(self, elgObj): # Check capabilities assert not elgObj.has_private() # Sanity check key data assert 1 < elgObj.g < (elgObj.p - 1) assert pow(elgObj.g, elgObj.p - 1, elgObj.p) == 1 def _exercise_primitive(self, elgObj): # Test encryption/decryption plaintext = 127218 ciphertext = elgObj._encrypt(plaintext, 123456789) plaintextP = elgObj._decrypt(ciphertext) assert plaintext == plaintextP # Test signature/verification signature = elgObj._sign(plaintext, 987654321) elgObj._verify(plaintext, signature) def _exercise_public_primitive(self, elgObj): plaintext = 92987276 elgObj._encrypt(plaintext, 123456789)