text: # ===================================================================
  #
  # Copyright (c) 2014, Legrandin <helderijs@gmail.com>
  # All rights reserved.
  #
  # Redistribution and use in source and binary forms, with or without
  # modification, are permitted provided that the following conditions
  # are met:
  #
  # 1. Redistributions of source code must retain the above copyright
  #    notice, this list of conditions and the following disclaimer.
  # 2. Redistributions in binary form must reproduce the above copyright
  #    notice, this list of conditions and the following disclaimer in
  #    the documentation and/or other materials provided with the
  #    distribution.
  #
  # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  # "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  # LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  # FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
  # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  # INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
  # BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  # LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  # CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  # LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  # ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  # POSSIBILITY OF SUCH DAMAGE.
  # ===================================================================
  
  import os
  import re
  import unittest
  from binascii import hexlify
  
  from Cryptodome.Util.py3compat import b, tobytes, bchr, _memoryview, unhexlify
  from Cryptodome.Util.strxor import strxor_c
  from Cryptodome.SelfTest.st_common import list_test_cases
  
  from Cryptodome.Cipher import ChaCha20
  
  
  class ChaCha20Test(unittest.TestCase):
  
      def test_new_positive(self):
          cipher = ChaCha20.new(key=b("0")*32, nonce=b"0"*8)
          self.assertEqual(cipher.nonce, b"0" * 8)
          cipher = ChaCha20.new(key=b("0")*32, nonce=b"0"*12)
          self.assertEqual(cipher.nonce, b"0" * 12)
  
      def test_new_negative(self):
          new = ChaCha20.new
          self.assertRaises(TypeError, new)
          self.assertRaises(TypeError, new, nonce=b("0"))
          self.assertRaises(ValueError, new, nonce=b("0")*8, key=b("0"))
          self.assertRaises(ValueError, new, nonce=b("0"), key=b("0")*32)
  
      def test_default_nonce(self):
          cipher1 = ChaCha20.new(key=bchr(1) * 32)
          cipher2 = ChaCha20.new(key=bchr(1) * 32)
          self.assertEquals(len(cipher1.nonce), 8)
          self.assertNotEqual(cipher1.nonce, cipher2.nonce)
  
      def test_eiter_encrypt_or_decrypt(self):
          """Verify that a cipher cannot be used for both decrypting and encrypting"""
  
          c1 = ChaCha20.new(key=b("5") * 32, nonce=b("6") * 8)
          c1.encrypt(b("8"))
          self.assertRaises(TypeError, c1.decrypt, b("9"))
  
          c2 = ChaCha20.new(key=b("5") * 32, nonce=b("6") * 8)
          c2.decrypt(b("8"))
          self.assertRaises(TypeError, c2.encrypt, b("9"))
  
      def test_round_trip(self):
          pt = b("A") * 1024
          c1 = ChaCha20.new(key=b("5") * 32, nonce=b("6") * 8)
          c2 = ChaCha20.new(key=b("5") * 32, nonce=b("6") * 8)
          ct = c1.encrypt(pt)
          self.assertEqual(c2.decrypt(ct), pt)
  
          self.assertEqual(c1.encrypt(b("")), b(""))
          self.assertEqual(c2.decrypt(b("")), b(""))
  
      def test_streaming(self):
          """Verify that an arbitrary number of bytes can be encrypted/decrypted"""
          from Cryptodome.Hash import SHA1
  
          segments = (1, 3, 5, 7, 11, 17, 23)
          total = sum(segments)
  
          pt = b("")
          while len(pt) < total:
              pt += SHA1.new(pt).digest()
  
          cipher1 = ChaCha20.new(key=b("7") * 32, nonce=b("t") * 8)
          ct = cipher1.encrypt(pt)
  
          cipher2 = ChaCha20.new(key=b("7") * 32, nonce=b("t") * 8)
          cipher3 = ChaCha20.new(key=b("7") * 32, nonce=b("t") * 8)
          idx = 0
          for segment in segments:
              self.assertEqual(cipher2.decrypt(ct[idx:idx+segment]), pt[idx:idx+segment])
              self.assertEqual(cipher3.encrypt(pt[idx:idx+segment]), ct[idx:idx+segment])
              idx += segment
  
      def test_seek(self):
          cipher1 = ChaCha20.new(key=b("9") * 32, nonce=b("e") * 8)
  
          offset = 64 * 900 + 7
          pt = b("1") * 64
  
          cipher1.encrypt(b("0") * offset)
          ct1 = cipher1.encrypt(pt)
  
          cipher2 = ChaCha20.new(key=b("9") * 32, nonce=b("e") * 8)
          cipher2.seek(offset)
          ct2 = cipher2.encrypt(pt)
  
          self.assertEquals(ct1, ct2)
  
      def test_seek_tv(self):
          # Test Vector #4, A.1 from
          # http://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
          key = bchr(0) + bchr(255) + bchr(0) * 30
          nonce = bchr(0) * 8
          cipher = ChaCha20.new(key=key, nonce=nonce)
          cipher.seek(64 * 2)
          expected_key_stream = unhexlify(b(
              "72d54dfbf12ec44b362692df94137f32"
              "8fea8da73990265ec1bbbea1ae9af0ca"
              "13b25aa26cb4a648cb9b9d1be65b2c09"
              "24a66c54d545ec1b7374f4872e99f096"
              ))
          ct = cipher.encrypt(bchr(0) * len(expected_key_stream))
          self.assertEqual(expected_key_stream, ct)
  
      def test_rfc7539(self):
          # from https://tools.ietf.org/html/rfc7539 Annex A.1
          # Each item is: key, nonce, block #, plaintext, ciphertext
          tvs = [
                  # Test Vector #1
                  (
                      "00"*32,
                      "00"*12,
                      0,
                      "00"*16*4,
                      "76b8e0ada0f13d90405d6ae55386bd28"
                      "bdd219b8a08ded1aa836efcc8b770dc7"
                      "da41597c5157488d7724e03fb8d84a37"
                      "6a43b8f41518a11cc387b669b2ee6586"
                  ),
                  # Test Vector #2
                  (
                      "00"*31 + "01",
                      "00"*11 + "02",
                      1,
                      "416e79207375626d697373696f6e2074"
                      "6f20746865204945544620696e74656e"
                      "6465642062792074686520436f6e7472"
                      "696275746f7220666f72207075626c69"
                      "636174696f6e20617320616c6c206f72"
                      "2070617274206f6620616e2049455446"
                      "20496e7465726e65742d447261667420"
                      "6f722052464320616e6420616e792073"
                      "746174656d656e74206d616465207769"
                      "7468696e2074686520636f6e74657874"
                      "206f6620616e20494554462061637469"
                      "7669747920697320636f6e7369646572"
                      "656420616e20224945544620436f6e74"
                      "7269627574696f6e222e205375636820"
                      "73746174656d656e747320696e636c75"
                      "6465206f72616c2073746174656d656e"
                      "747320696e2049455446207365737369"
                      "6f6e732c2061732077656c6c20617320"
                      "7772697474656e20616e6420656c6563"
                      "74726f6e696320636f6d6d756e696361"
                      "74696f6e73206d61646520617420616e"
                      "792074696d65206f7220706c6163652c"
                      "20776869636820617265206164647265"
                      "7373656420746f",
                      "a3fbf07df3fa2fde4f376ca23e827370"
                      "41605d9f4f4f57bd8cff2c1d4b7955ec"
                      "2a97948bd3722915c8f3d337f7d37005"
                      "0e9e96d647b7c39f56e031ca5eb6250d"
                      "4042e02785ececfa4b4bb5e8ead0440e"
                      "20b6e8db09d881a7c6132f420e527950"
                      "42bdfa7773d8a9051447b3291ce1411c"
                      "680465552aa6c405b7764d5e87bea85a"
                      "d00f8449ed8f72d0d662ab052691ca66"
                      "424bc86d2df80ea41f43abf937d3259d"
                      "c4b2d0dfb48a6c9139ddd7f76966e928"
                      "e635553ba76c5c879d7b35d49eb2e62b"
                      "0871cdac638939e25e8a1e0ef9d5280f"
                      "a8ca328b351c3c765989cbcf3daa8b6c"
                      "cc3aaf9f3979c92b3720fc88dc95ed84"
                      "a1be059c6499b9fda236e7e818b04b0b"
                      "c39c1e876b193bfe5569753f88128cc0"
                      "8aaa9b63d1a16f80ef2554d7189c411f"
                      "5869ca52c5b83fa36ff216b9c1d30062"
                      "bebcfd2dc5bce0911934fda79a86f6e6"
                      "98ced759c3ff9b6477338f3da4f9cd85"
                      "14ea9982ccafb341b2384dd902f3d1ab"
                      "7ac61dd29c6f21ba5b862f3730e37cfd"
                      "c4fd806c22f221"
                  ),
                  # Test Vector #3
                  (
                      "1c9240a5eb55d38af333888604f6b5f0"
                      "473917c1402b80099dca5cbc207075c0",
                      "00"*11 + "02",
                      42,
                      "2754776173206272696c6c69672c2061"
                      "6e642074686520736c6974687920746f"
                      "7665730a446964206779726520616e64"
                      "2067696d626c6520696e207468652077"
                      "6162653a0a416c6c206d696d73792077"
                      "6572652074686520626f726f676f7665"
                      "732c0a416e6420746865206d6f6d6520"
                      "7261746873206f757467726162652e",
                      "62e6347f95ed87a45ffae7426f27a1df"
                      "5fb69110044c0d73118effa95b01e5cf"
                      "166d3df2d721caf9b21e5fb14c616871"
                      "fd84c54f9d65b283196c7fe4f60553eb"
                      "f39c6402c42234e32a356b3e764312a6"
                      "1a5532055716ead6962568f87d3f3f77"
                      "04c6a8d1bcd1bf4d50d6154b6da731b1"
                      "87b58dfd728afa36757a797ac188d1"
                  )
          ]
  
          for tv in tvs:
              key = unhexlify(tv[0])
              nonce = unhexlify(tv[1])
              offset = tv[2] * 64
              pt = unhexlify(tv[3])
              ct_expect = unhexlify(tv[4])
  
              cipher = ChaCha20.new(key=key, nonce=nonce)
              if offset != 0:
                  cipher.seek(offset)
              ct = cipher.encrypt(pt)
              assert(ct == ct_expect)
  
  
  class ByteArrayTest(unittest.TestCase):
      """Verify we can encrypt or decrypt bytearrays"""
  
      def runTest(self):
  
          data = b"0123"
          key = b"9" * 32
          nonce = b"t" * 8
  
          # Encryption
          data_ba = bytearray(data)
          key_ba = bytearray(key)
          nonce_ba = bytearray(nonce)
  
          cipher1 = ChaCha20.new(key=key, nonce=nonce)
          ct = cipher1.encrypt(data)
  
          cipher2 = ChaCha20.new(key=key_ba, nonce=nonce_ba)
          key_ba[:1] = b'\xFF'
          nonce_ba[:1] = b'\xFF'
          ct_test = cipher2.encrypt(data_ba)
  
          self.assertEqual(ct, ct_test)
          self.assertEqual(cipher1.nonce, cipher2.nonce)
  
          # Decryption
          key_ba = bytearray(key)
          nonce_ba = bytearray(nonce)
          ct_ba = bytearray(ct)
  
          cipher3 = ChaCha20.new(key=key_ba, nonce=nonce_ba)
          key_ba[:1] = b'\xFF'
          nonce_ba[:1] = b'\xFF'
          pt_test = cipher3.decrypt(ct_ba)
  
          self.assertEqual(data, pt_test)
  
  
  class MemoryviewTest(unittest.TestCase):
      """Verify we can encrypt or decrypt bytearrays"""
  
      def runTest(self):
  
          data = b"0123"
          key = b"9" * 32
          nonce = b"t" * 8
  
          # Encryption
          data_mv = memoryview(bytearray(data))
          key_mv = memoryview(bytearray(key))
          nonce_mv = memoryview(bytearray(nonce))
  
          cipher1 = ChaCha20.new(key=key, nonce=nonce)
          ct = cipher1.encrypt(data)
  
          cipher2 = ChaCha20.new(key=key_mv, nonce=nonce_mv)
          key_mv[:1] = b'\xFF'
          nonce_mv[:1] = b'\xFF'
          ct_test = cipher2.encrypt(data_mv)
  
          self.assertEqual(ct, ct_test)
          self.assertEqual(cipher1.nonce, cipher2.nonce)
  
          # Decryption
          key_mv = memoryview(bytearray(key))
          nonce_mv = memoryview(bytearray(nonce))
          ct_mv = memoryview(bytearray(ct))
  
          cipher3 = ChaCha20.new(key=key_mv, nonce=nonce_mv)
          key_mv[:1] = b'\xFF'
          nonce_mv[:1] = b'\xFF'
          pt_test = cipher3.decrypt(ct_mv)
  
          self.assertEqual(data, pt_test)
  
  
  class ChaCha20_AGL_NIR(unittest.TestCase):
  
      # From http://tools.ietf.org/html/draft-agl-tls-chacha20poly1305-04
      # and http://tools.ietf.org/html/draft-nir-cfrg-chacha20-poly1305-04
      tv = [
            ( "00" * 32,
              "00" * 8,
              "76b8e0ada0f13d90405d6ae55386bd28bdd219b8a08ded1aa836efcc"
              "8b770dc7da41597c5157488d7724e03fb8d84a376a43b8f41518a11c"
              "c387b669b2ee6586"
              "9f07e7be5551387a98ba977c732d080d"
              "cb0f29a048e3656912c6533e32ee7aed"
              "29b721769ce64e43d57133b074d839d5"
              "31ed1f28510afb45ace10a1f4b794d6f"
            ),
            ( "00" * 31 + "01",
              "00" * 8,
              "4540f05a9f1fb296d7736e7b208e3c96eb4fe1834688d2604f450952"
              "ed432d41bbe2a0b6ea7566d2a5d1e7e20d42af2c53d792b1c43fea81"
              "7e9ad275ae546963"
              "3aeb5224ecf849929b9d828db1ced4dd"
              "832025e8018b8160b82284f3c949aa5a"
              "8eca00bbb4a73bdad192b5c42f73f2fd"
              "4e273644c8b36125a64addeb006c13a0"
            ),
            ( "00" * 32,
              "00" * 7 + "01",
              "de9cba7bf3d69ef5e786dc63973f653a0b49e015adbff7134fcb7df1"
              "37821031e85a050278a7084527214f73efc7fa5b5277062eb7a0433e"
              "445f41e3"
            ),
            ( "00" * 32,
              "01" + "00" * 7,
              "ef3fdfd6c61578fbf5cf35bd3dd33b8009631634d21e42ac33960bd1"
              "38e50d32111e4caf237ee53ca8ad6426194a88545ddc497a0b466e7d"
              "6bbdb0041b2f586b"
            ),
            ( "000102030405060708090a0b0c0d0e0f101112131415161718191a1b"
              "1c1d1e1f",
              "0001020304050607",
              "f798a189f195e66982105ffb640bb7757f579da31602fc93ec01ac56"
              "f85ac3c134a4547b733b46413042c9440049176905d3be59ea1c53f1"
              "5916155c2be8241a38008b9a26bc35941e2444177c8ade6689de9526"
              "4986d95889fb60e84629c9bd9a5acb1cc118be563eb9b3a4a472f82e"
              "09a7e778492b562ef7130e88dfe031c79db9d4f7c7a899151b9a4750"
              "32b63fc385245fe054e3dd5a97a5f576fe064025d3ce042c566ab2c5"
              "07b138db853e3d6959660996546cc9c4a6eafdc777c040d70eaf46f7"
              "6dad3979e5c5360c3317166a1c894c94a371876a94df7628fe4eaaf2"
              "ccb27d5aaae0ad7ad0f9d4b6ad3b54098746d4524d38407a6deb3ab7"
              "8fab78c9"
            ),
            ( "00" * 32,
              "00" * 7 + "02",
              "c2c64d378cd536374ae204b9ef933fcd"
              "1a8b2288b3dfa49672ab765b54ee27c7"
              "8a970e0e955c14f3a88e741b97c286f7"
              "5f8fc299e8148362fa198a39531bed6d"
            ),
           ]
  
      def runTest(self):
          for (key, nonce, stream) in self.tv:
              c = ChaCha20.new(key=unhexlify(b(key)), nonce=unhexlify(b(nonce)))
              ct = unhexlify(b(stream))
              pt = b("\x00") * len(ct)
              self.assertEqual(c.encrypt(pt), ct)
  
  
  def get_tests(config={}):
      tests = []
      tests += list_test_cases(ChaCha20Test)
      tests.append(ChaCha20_AGL_NIR())
      tests.append(ByteArrayTest())
  
      import types
      if _memoryview != types.NoneType:
          tests.append(MemoryviewTest())
  
      return tests
  
  
  if __name__ == '__main__':
      import unittest
      suite = lambda: unittest.TestSuite(get_tests())
      unittest.main(defaultTest='suite')
  