def test_put_bitstream_copy_self(self):
"""
Test using the put_bitstream_copy method with the same BitStream object
as origin and destination.
"""
bitstream = BitStream()
# Generate a random string of bits, ie: ('0' | '1')*
num_bits = 50
bits = ""
for i in range(0,num_bits):
bits += random.choice(('0','1')) # inefficient, but ok for a test.
# Put those bits in the BitStream...
bitstream.put_bit_dump_string(bits)
# ... copy the bitstream into itself at any point:
bitstream.seek(random.randint(0,50))
bitstream.put_bitstream_copy(bitstream)
# Check that the bitstream was unchanged by the previous operation:
# (overwriting data with the same data is the same as doing nothing,
# except that the current position is changed to the end of the stream)
self.assertEquals(bitstream.get_length(),num_bits)
self.assertEquals(bitstream.get_current_pos(),num_bits)
bitstream.seek(0)
read_bits = bitstream.get_bit_dump_string(bitstream.get_length())
self.assertEqual(read_bits, bits)
def test_put_bitstream_copy_self(self):
"""
Test using the put_bitstream_copy method with the same BitStream object
as origin and destination.
"""
bitstream = BitStream()
# Generate a random string of bits, ie: ('0' | '1')*
num_bits = 50
bits = ""
for i in range(0, num_bits):
bits += random.choice(
('0', '1')) # inefficient, but ok for a test.
# Put those bits in the BitStream...
bitstream.put_bit_dump_string(bits)
# ... copy the bitstream into itself at any point:
bitstream.seek(random.randint(0, 50))
bitstream.put_bitstream_copy(bitstream)
# Check that the bitstream was unchanged by the previous operation:
# (overwriting data with the same data is the same as doing nothing,
# except that the current position is changed to the end of the stream)
self.assertEquals(bitstream.get_length(), num_bits)
self.assertEquals(bitstream.get_current_pos(), num_bits)
bitstream.seek(0)
read_bits = bitstream.get_bit_dump_string(bitstream.get_length())
self.assertEqual(read_bits, bits)
def test_string_character_zero(self):
"""
Test that we are handling character zero ('\\0') correctly.
"""
bitstream = BitStream()
bitstream.put_string("Evil \0String.") # 13 chars/bytes
self.assertEquals(bitstream.get_length(), 13 * 8)
bitstream.seek(0)
self.assertEquals(bitstream.get_string(bitstream.get_length()),
"Evil \0String.")
def test_string_character_zero(self):
"""
Test that we are handling character zero ('\\0') correctly.
"""
bitstream = BitStream()
bitstream.put_string("Evil \0String.") # 13 chars/bytes
self.assertEquals(bitstream.get_length(),13*8)
bitstream.seek(0)
self.assertEquals(bitstream.get_string(bitstream.get_length()),
"Evil \0String.")
def test_multiformat_write_multiformat_read(self):
"""
This test writes numeric, byte and string data to a stream and then
reads the whole stream as binary, hex and base64 data, ensuring that
the output is the expected one in each case.
"""
# Write a number, 2 bytes and a string
bitstream = BitStream()
bitstream.put_num(10438341575639894917, 64)
bitstream.put_byte(230)
bitstream.put_byte(191)
bitstream.put_string("ÄäÜüßTestЯБГДЖЙŁĄŻStringĘĆŃŚŹてす" \
"とｱｲｳｴｵｶｷｸ4234ｹｺｻｼｽｾｿﾀﾁﾂﾃ")
# Read in binary, hex and base64 formats
expected_bits = \
"1001000011011100011100000101101110111100001101010000101110000101" \
"1110011010111111110000111000010011000011101001001100001110011100" \
"1100001110111100110000111001111101010100011001010111001101110100" \
"1101000010101111110100001001000111010000100100111101000010010100" \
"1101000010010110110100001001100111000101100000011100010010000100" \
"1100010110111011010100110111010001110010011010010110111001100111" \
"1100010010011000110001001000011011000101100000111100010110011010" \
"1100010110111001111000111000000110100110111000111000000110011001" \
"1110001110000001101010001110111110111101101100011110111110111101" \
"1011001011101111101111011011001111101111101111011011010011101111" \
"1011110110110101111011111011110110110110111011111011110110110111" \
"1110111110111101101110000011010000110010001100110011010011101111" \
"1011110110111001111011111011110110111010111011111011110110111011" \
"1110111110111101101111001110111110111101101111011110111110111101" \
"1011111011101111101111011011111111101111101111101000000011101111" \
"1011111010000001111011111011111010000010111011111011111010000011"
expected_hex = \
"90dc705bbc350b85e6bfc384c3a4c39cc3bcc39f54657374d0afd091d093d094" \
"d096d099c581c484c5bb537472696e67c498c486c583c59ac5b9e381a6e38199" \
"e381a8efbdb1efbdb2efbdb3efbdb4efbdb5efbdb6efbdb7efbdb834323334ef" \
"bdb9efbdbaefbdbbefbdbcefbdbdefbdbeefbdbfefbe80efbe81efbe82efbe83"
expected_base64 = \
"kNxwW7w1C4Xmv8OEw6TDnMO8w59UZXN00K/QkdCT0JTQltCZxYHEhMW7U3RyaW5n" \
"xJjEhsWDxZrFueOBpuOBmeOBqO+9se+9su+9s++9tO+9te+9tu+9t++9uDQyMzTv" \
"vbnvvbrvvbvvvbzvvb3vvb7vvb/vvoDvvoHvvoLvvoM="
bitstream.seek(0)
self.assertEquals( \
bitstream.get_bit_dump_string(bitstream.get_length()),
expected_bits)
bitstream.seek(0)
self.assertEquals(bitstream.get_hex(bitstream.get_length()).lower(),
expected_hex)
bitstream.seek(0)
self.assertEquals(bitstream.get_base64(bitstream.get_length()),
expected_base64)
def test_multiformat_write_multiformat_read(self):
"""
This test writes numeric, byte and string data to a stream and then
reads the whole stream as binary, hex and base64 data, ensuring that
the output is the expected one in each case.
"""
# Write a number, 2 bytes and a string
bitstream = BitStream()
bitstream.put_num(10438341575639894917, 64)
bitstream.put_byte(230)
bitstream.put_byte(191)
bitstream.put_string("ÄäÜüßTestЯБГДЖЙŁĄŻStringĘĆŃŚŹてす" \
"とｱｲｳｴｵｶｷｸ4234ｹｺｻｼｽｾｿﾀﾁﾂﾃ")
# Read in binary, hex and base64 formats
expected_bits = \
"1001000011011100011100000101101110111100001101010000101110000101" \
"1110011010111111110000111000010011000011101001001100001110011100" \
"1100001110111100110000111001111101010100011001010111001101110100" \
"1101000010101111110100001001000111010000100100111101000010010100" \
"1101000010010110110100001001100111000101100000011100010010000100" \
"1100010110111011010100110111010001110010011010010110111001100111" \
"1100010010011000110001001000011011000101100000111100010110011010" \
"1100010110111001111000111000000110100110111000111000000110011001" \
"1110001110000001101010001110111110111101101100011110111110111101" \
"1011001011101111101111011011001111101111101111011011010011101111" \
"1011110110110101111011111011110110110110111011111011110110110111" \
"1110111110111101101110000011010000110010001100110011010011101111" \
"1011110110111001111011111011110110111010111011111011110110111011" \
"1110111110111101101111001110111110111101101111011110111110111101" \
"1011111011101111101111011011111111101111101111101000000011101111" \
"1011111010000001111011111011111010000010111011111011111010000011"
expected_hex = \
"90dc705bbc350b85e6bfc384c3a4c39cc3bcc39f54657374d0afd091d093d094" \
"d096d099c581c484c5bb537472696e67c498c486c583c59ac5b9e381a6e38199" \
"e381a8efbdb1efbdb2efbdb3efbdb4efbdb5efbdb6efbdb7efbdb834323334ef" \
"bdb9efbdbaefbdbbefbdbcefbdbdefbdbeefbdbfefbe80efbe81efbe82efbe83"
expected_base64 = \
"kNxwW7w1C4Xmv8OEw6TDnMO8w59UZXN00K/QkdCT0JTQltCZxYHEhMW7U3RyaW5n" \
"xJjEhsWDxZrFueOBpuOBmeOBqO+9se+9su+9s++9tO+9te+9tu+9t++9uDQyMzTv" \
"vbnvvbrvvbvvvbzvvb3vvb7vvb/vvoDvvoHvvoLvvoM="
bitstream.seek(0)
self.assertEquals( \
bitstream.get_bit_dump_string(bitstream.get_length()),
expected_bits)
bitstream.seek(0)
self.assertEquals(
bitstream.get_hex(bitstream.get_length()).lower(), expected_hex)
bitstream.seek(0)
self.assertEquals(bitstream.get_base64(bitstream.get_length()),
expected_base64)
def test_byte_basic(self):
"""
Test basic put_byte and get_byte behavior.
"""
bitstream = BitStream()
# Put a couple of bytes in the stream:
bytes = [ 12, # 00001100
222, # 11011110
145, # 10010001
42, # 00101010
0, # 00000000
255] # 11111111
for byte in bytes:
bitstream.put_byte(byte)
# Sanity check:
self.assertEquals(bitstream.get_length(),len(bytes)*8)
self.assertEquals(bitstream.get_current_pos(),len(bytes)*8)
# Read the bytes back from the stream
bitstream.seek(0)
for byte in bytes:
self.assertEquals(bitstream.get_byte(), byte)
# Read some bits from the stream, interpreting them as bytes, but
# without restricting ourselves to 8-bit aligned bytes
# e.g. read the "byte" defined by bits #4 to #12
bitstream.seek(4)
self.assertEquals(bitstream.get_byte(), 205) # 11001101
bitstream.seek(19)
self.assertEquals(bitstream.get_byte(), 137) # 10001001
def test_string_ascii(self):
"""
Test basic put_string and get_string behavior, using ASCII strings.
"""
bitstream = BitStream()
string1 = "Test string " # 12 chars/bytes
string2 = "using only ASCII characters (0-126):\n\t" # 38 chars/bytes
string3 = "Hello World!" # 12 chars/bytes
# Store our message in 3 writes
bitstream.put_string(string1)
bitstream.put_string(string2)
bitstream.put_string(string3)
# Sanity check:
self.assertEquals(bitstream.get_length(), (12 + 38 + 12) * 8)
self.assertEquals(bitstream.get_current_pos(), (12 + 38 + 12) * 8)
# Retrieve our message in 2 reads
bitstream.seek(0)
self.assertEquals(
bitstream.get_string(29 * 8), # read 29 bytes
"Test string using only ASCII ")
self.assertEquals(
bitstream.get_string(33 * 8), # read 33 bytes
"characters (0-126):\n\tHello World!")
def test_stress(self):
"""
Stress test BitStream by writings lots of numbers of different bit
sizes and reading them back.
"""
# num_writes = 10000
num_writes = 1000
min_bit_length = 1
max_bit_length = 8192
# Generate the numbers
nums = []
total_bit_length = 0
for i in range(0, num_writes):
bit_length = random.randint(min_bit_length, max_bit_length)
total_bit_length += bit_length
val = random.randint(0, 2**bit_length - 1)
nums.append({"bit_length" : bit_length, "value" : val})
# Write them to a BitStream object
bitstream = BitStream()
for num in nums:
bitstream.put_num(num["value"], num["bit_length"])
# Check the BitStream length and current position
self.assertEquals(bitstream.get_length(),total_bit_length)
self.assertEquals(bitstream.get_current_pos(),total_bit_length)
# Read all numbers back
bitstream.seek(0)
for num in nums:
self.assertEquals(bitstream.get_num(num["bit_length"]),num["value"])
def test_stress(self):
"""
Stress test BitStream by writings lots of numbers of different bit
sizes and reading them back.
"""
# num_writes = 10000
num_writes = 1000
min_bit_length = 1
max_bit_length = 8192
# Generate the numbers
nums = []
total_bit_length = 0
for i in range(0, num_writes):
bit_length = random.randint(min_bit_length, max_bit_length)
total_bit_length += bit_length
val = random.randint(0, 2**bit_length - 1)
nums.append({"bit_length": bit_length, "value": val})
# Write them to a BitStream object
bitstream = BitStream()
for num in nums:
bitstream.put_num(num["value"], num["bit_length"])
# Check the BitStream length and current position
self.assertEquals(bitstream.get_length(), total_bit_length)
self.assertEquals(bitstream.get_current_pos(), total_bit_length)
# Read all numbers back
bitstream.seek(0)
for num in nums:
self.assertEquals(bitstream.get_num(num["bit_length"]),
num["value"])
def test_bitstream_constructor(self):
"""
Test that creating an empty bitstream succeeds.
"""
bitstream = BitStream()
# An empty bitstream has length 0 ...
self.assertEqual(bitstream.get_length(), 0)
# ...and has its current position marker at position 0.
self.assertEqual(bitstream.get_current_pos(), 0)
def test_bitstream_constructor(self):
"""
Test that creating an empty bitstream succeeds.
"""
bitstream = BitStream()
# An empty bitstream has length 0 ...
self.assertEqual(bitstream.get_length(), 0)
# ...and has its current position marker at position 0.
self.assertEqual(bitstream.get_current_pos(), 0)
def test_put_bitstream_copy(self):
"""
Test the basic functionality of the put_bitstream_copy method.
"""
bitstream1 = BitStream()
bitstream1.put_string("This is bitstream1")
bitstream2 = BitStream()
bitstream2.put_string("This is bitstream2")
bitstream3 = BitStream()
# bitstream3 remains empty
bitstream4 = BitStream()
bitstream4.put_string("This is bitstream4")
# copy the full contents of bitstream2 to the end of bitstream1
bitstream2.seek(0)
bitstream1.put_bitstream_copy(bitstream2)
self.assertEquals(bitstream2.get_current_pos(),
bitstream2.get_length())
# check the contents of bitstream1
bitstream1.seek(0)
self.assertEquals(bitstream1.get_string(bitstream1.get_length()),
"This is bitstream1This is bitstream2")
# copy the full contents of bitstream3 (aka. nothing) to the end of
# bitstream4
bitstream3.seek(0)
bitstream4.put_bitstream_copy(bitstream3)
# check the contents of bitstream4
bitstream4.seek(0)
self.assertEquals(bitstream4.get_string(bitstream4.get_length()),
"This is bitstream4")
# copy the contents of bitstream4 from the position 8 onwards
bitstream4.seek(8 * 8)
bitstream1.put_bitstream_copy(bitstream4)
self.assertEquals(bitstream4.get_current_pos(),
bitstream4.get_length())
# check the contents of bitstream1
bitstream1.seek(0)
self.assertEquals(bitstream1.get_string(bitstream1.get_length()),
"This is bitstream1This is bitstream2bitstream4")
def test_put_bitstream_copy(self):
"""
Test the basic functionality of the put_bitstream_copy method.
"""
bitstream1 = BitStream()
bitstream1.put_string("This is bitstream1")
bitstream2 = BitStream()
bitstream2.put_string("This is bitstream2")
bitstream3 = BitStream()
# bitstream3 remains empty
bitstream4 = BitStream()
bitstream4.put_string("This is bitstream4")
# copy the full contents of bitstream2 to the end of bitstream1
bitstream2.seek(0)
bitstream1.put_bitstream_copy(bitstream2)
self.assertEquals(bitstream2.get_current_pos(), bitstream2.get_length())
# check the contents of bitstream1
bitstream1.seek(0)
self.assertEquals(bitstream1.get_string(bitstream1.get_length()),
"This is bitstream1This is bitstream2")
# copy the full contents of bitstream3 (aka. nothing) to the end of
# bitstream4
bitstream3.seek(0)
bitstream4.put_bitstream_copy(bitstream3)
# check the contents of bitstream4
bitstream4.seek(0)
self.assertEquals(bitstream4.get_string(bitstream4.get_length()),
"This is bitstream4")
# copy the contents of bitstream4 from the position 8 onwards
bitstream4.seek(8*8)
bitstream1.put_bitstream_copy(bitstream4)
self.assertEquals(bitstream4.get_current_pos(), bitstream4.get_length())
# check the contents of bitstream1
bitstream1.seek(0)
self.assertEquals(bitstream1.get_string(bitstream1.get_length()),
"This is bitstream1This is bitstream2bitstream4")
def test_base64_basic(self):
"""
This method tests put_base64's and get_base64's basic functionality.
"""
bitstream = BitStream()
# We use the Base64 Test Vectors defined in RFC4648.
# http://www.ietf.org/rfc/rfc4648.txt
test_vectors = [("",""),
("f","Zg=="),
("fo","Zm8="),
("foo","Zm9v"),
("foob","Zm9vYg=="),
("fooba","Zm9vYmE="),
("foobar","Zm9vYmFy")]
# STEP 1:
# For each test vector, we write its value to the bitstream as a string
# then read it as base64 data.
for (str_val, base64_val) in test_vectors:
vector_bit_length = len(str_val)*8
bitstream.put_string(str_val)
bitstream.seek(0)
self.assertEquals(bitstream.get_base64(vector_bit_length),
base64_val)
bitstream.seek(0)
# NOTE that we are overwriting multiple times our bitstream, this is
# also a feature of BitStream we are testing in this test case.
# STEP 2:
# For each test vector, we write its value to the bitstream as base64
# data, then read it as string *and* base64 data.
for (str_val, base64_val) in test_vectors:
vector_bit_length = len(str_val)*8
bitstream.put_base64(base64_val)
bitstream.seek(0)
self.assertEquals(bitstream.get_string(vector_bit_length),
str_val)
bitstream.seek(0)
self.assertEquals(bitstream.get_base64(vector_bit_length),
base64_val)
bitstream.seek(0)
# STEP 3:
# For each test vector, we write its value to a NEW bitstream as base64
# data, and make sure the length of the stream is the expected one.
for (str_val, base64_val) in test_vectors:
vector_bit_length = len(str_val)*8
new_bs = BitStream()
new_bs.put_base64(base64_val)
self.assertEquals(new_bs.get_length(), vector_bit_length)
self.assertEquals(new_bs.get_current_pos(), vector_bit_length)
def test_string_unicode(self):
"""
Test basic put_string and get_string support for python unicode objects.
"""
bitstream = BitStream()
unicode_string = u"ÄäÜüßЯБГДЖЙŁĄŻĘĆŃŚŹてすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ"
bitstream.put_string(unicode_string)
bitstream.seek(0)
# Note: the string is read back as a "normal" UTF-8 string, unicode
# type information is not stored in the bitstream.
self.assertEquals(bitstream.get_string(bitstream.get_length()),
"ÄäÜüßЯБГДЖЙŁĄŻĘĆŃŚŹてすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ")
def test_string_unicode(self):
"""
Test basic put_string and get_string support for python unicode objects.
"""
bitstream = BitStream()
unicode_string = u"ÄäÜüßЯБГДЖЙŁĄŻĘĆŃŚŹてすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ"
bitstream.put_string(unicode_string)
bitstream.seek(0)
# Note: the string is read back as a "normal" UTF-8 string, unicode
# type information is not stored in the bitstream.
self.assertEquals(bitstream.get_string(bitstream.get_length()),
"ÄäÜüßЯБГДЖЙŁĄŻĘĆŃŚŹてすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ")
def test_string_utf8(self):
"""
Test basic put_string and get_string support for UTF-8 strings.
"""
bitstream = BitStream()
string1 = "ÄäÜüß" # 5 chars, 10 bytes
string2 = "ЯБГДЖЙŁĄŻĘĆŃŚŹ" # 14 chars, 28 bytes
string3 = "てすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ" # 22 chars, 66 bytes
# Store our message in 3 writes
bitstream.put_string(string1)
bitstream.put_string(string2)
bitstream.put_string(string3)
# Sanity check:
self.assertEquals(bitstream.get_length(), (10 + 28 + 66) * 8)
self.assertEquals(bitstream.get_current_pos(), (10 + 28 + 66) * 8)
# Retrieve the whole message
bitstream.seek(0)
self.assertEquals(bitstream.get_string(bitstream.get_length()),
"ÄäÜüßЯБГДЖЙŁĄŻĘĆŃŚŹてすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ")
def test_string_utf8(self):
"""
Test basic put_string and get_string support for UTF-8 strings.
"""
bitstream = BitStream()
string1 = "ÄäÜüß" # 5 chars, 10 bytes
string2 = "ЯБГДЖЙŁĄŻĘĆŃŚŹ" # 14 chars, 28 bytes
string3 = "てすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ" # 22 chars, 66 bytes
# Store our message in 3 writes
bitstream.put_string(string1)
bitstream.put_string(string2)
bitstream.put_string(string3)
# Sanity check:
self.assertEquals(bitstream.get_length(),(10+28+66)*8)
self.assertEquals(bitstream.get_current_pos(),(10+28+66)*8)
# Retrieve the whole message
bitstream.seek(0)
self.assertEquals(bitstream.get_string(bitstream.get_length()),
"ÄäÜüßЯБГДЖЙŁĄŻĘĆŃŚŹてすとｱｲｳｴｵｶｷｸｹｺｻｼｽｾｿﾀﾁﾂﾃ")
def test_base64_basic(self):
"""
This method tests put_base64's and get_base64's basic functionality.
"""
bitstream = BitStream()
# We use the Base64 Test Vectors defined in RFC4648.
# http://www.ietf.org/rfc/rfc4648.txt
test_vectors = [("", ""), ("f", "Zg=="), ("fo", "Zm8="),
("foo", "Zm9v"), ("foob", "Zm9vYg=="),
("fooba", "Zm9vYmE="), ("foobar", "Zm9vYmFy")]
# STEP 1:
# For each test vector, we write its value to the bitstream as a string
# then read it as base64 data.
for (str_val, base64_val) in test_vectors:
vector_bit_length = len(str_val) * 8
bitstream.put_string(str_val)
bitstream.seek(0)
self.assertEquals(bitstream.get_base64(vector_bit_length),
base64_val)
bitstream.seek(0)
# NOTE that we are overwriting multiple times our bitstream, this is
# also a feature of BitStream we are testing in this test case.
# STEP 2:
# For each test vector, we write its value to the bitstream as base64
# data, then read it as string *and* base64 data.
for (str_val, base64_val) in test_vectors:
vector_bit_length = len(str_val) * 8
bitstream.put_base64(base64_val)
bitstream.seek(0)
self.assertEquals(bitstream.get_string(vector_bit_length), str_val)
bitstream.seek(0)
self.assertEquals(bitstream.get_base64(vector_bit_length),
base64_val)
bitstream.seek(0)
# STEP 3:
# For each test vector, we write its value to a NEW bitstream as base64
# data, and make sure the length of the stream is the expected one.
for (str_val, base64_val) in test_vectors:
vector_bit_length = len(str_val) * 8
new_bs = BitStream()
new_bs.put_base64(base64_val)
self.assertEquals(new_bs.get_length(), vector_bit_length)
self.assertEquals(new_bs.get_current_pos(), vector_bit_length)
def test_put_hex_invalid_format(self):
"""
Test that put_hex raises an exception when passed any string not of the
form ('0'-'9'|'a'-'f'|'A'-'F')*
"""
bitstream = BitStream()
# Try some fixed examples
self.assertRaises(ValueError, bitstream.put_hex, "aF92G2")
self.assertRaises(ValueError, bitstream.put_hex, "Hello")
self.assertRaises(ValueError, bitstream.put_hex, "3354 F")
self.assertRaises(ValueError, bitstream.put_hex, "ｹｺｻｼｽ")
# Generate a random string conforming to ('0'-'9'|'a'-'f'|'A'-'F')*
# except for one (ascii) character.
valid_hex_digits = "0123456789abcdefABCDEF"
num_digits = 50
pos_wrong_char = random.randint(1, 48)
r_invalid_hex_string = ""
for i in range(0, pos_wrong_char):
r_invalid_hex_string += random.choice(valid_hex_digits)
non_hex_char = "0"
while (non_hex_char in valid_hex_digits):
non_hex_char = \
random.choice(string.letters + string.digits + string.whitespace)
r_invalid_hex_string += non_hex_char
for i in range(0, num_digits - pos_wrong_char - 1):
r_invalid_hex_string += random.choice(valid_hex_digits)
# Try the randomly generated example
self.assertRaises(ValueError, bitstream.put_hex, r_invalid_hex_string)
# Calls that throw exceptions should not alter the contents or position
# of the bitstream:
self.assertEquals(bitstream.get_length(), 0)
self.assertEquals(bitstream.get_current_pos(), 0)
def test_put_hex_invalid_format(self):
"""
Test that put_hex raises an exception when passed any string not of the
form ('0'-'9'|'a'-'f'|'A'-'F')*
"""
bitstream = BitStream()
# Try some fixed examples
self.assertRaises(ValueError, bitstream.put_hex, "aF92G2")
self.assertRaises(ValueError, bitstream.put_hex, "Hello")
self.assertRaises(ValueError, bitstream.put_hex, "3354 F")
self.assertRaises(ValueError, bitstream.put_hex, "ｹｺｻｼｽ")
# Generate a random string conforming to ('0'-'9'|'a'-'f'|'A'-'F')*
# except for one (ascii) character.
valid_hex_digits = "0123456789abcdefABCDEF"
num_digits = 50
pos_wrong_char = random.randint(1,48)
r_invalid_hex_string = ""
for i in range(0,pos_wrong_char):
r_invalid_hex_string += random.choice(valid_hex_digits)
non_hex_char = "0"
while(non_hex_char in valid_hex_digits):
non_hex_char = \
random.choice(string.letters + string.digits + string.whitespace)
r_invalid_hex_string += non_hex_char
for i in range(0,num_digits - pos_wrong_char - 1):
r_invalid_hex_string += random.choice(valid_hex_digits)
# Try the randomly generated example
self.assertRaises(ValueError, bitstream.put_hex, r_invalid_hex_string)
# Calls that throw exceptions should not alter the contents or position
# of the bitstream:
self.assertEquals(bitstream.get_length(),0)
self.assertEquals(bitstream.get_current_pos(),0)
def test_num_basic(self):
"""
Test basic put_num and get_num behavior
"""
bitstream = BitStream()
# Some parameters
num_sizes = [4, 8, 16, 32, 64, 128, 256, 2839]
num_writes = 10
nums = []
# Add num_writes integers of each size to nums:
for i in range(0, len(num_sizes)):
max_val = 2**num_sizes[i] - 1
nums.append([])
for j in range(0, num_writes):
# append a random number between 0 and max_val, inclusive
nums[i].append(random.randint(0, max_val))
# Write all values in nums to the stream
for i in range(0, len(num_sizes)):
for j in range(0, num_writes):
bitstream.put_num(nums[i][j], num_sizes[i])
# Go back to start of the stream
bitstream.seek(0)
# Sanity check:
expected_length = 0
for num_size in num_sizes:
expected_length += num_size * num_writes
self.assertEqual(bitstream.get_length(), expected_length)
# Read them back and compare
for i in range(0, len(num_sizes)):
for j in range(0, num_writes):
n = bitstream.get_num(num_sizes[i])
self.assertEqual(n, nums[i][j])
def test_num_basic(self):
"""
Test basic put_num and get_num behavior
"""
bitstream = BitStream()
# Some parameters
num_sizes = [4,8,16,32,64,128,256,2839]
num_writes = 10
nums = []
# Add num_writes integers of each size to nums:
for i in range(0,len(num_sizes)):
max_val = 2**num_sizes[i] - 1
nums.append([])
for j in range(0,num_writes):
# append a random number between 0 and max_val, inclusive
nums[i].append(random.randint(0, max_val))
# Write all values in nums to the stream
for i in range(0,len(num_sizes)):
for j in range(0,num_writes):
bitstream.put_num(nums[i][j], num_sizes[i])
# Go back to start of the stream
bitstream.seek(0)
# Sanity check:
expected_length = 0
for num_size in num_sizes: expected_length += num_size * num_writes
self.assertEqual(bitstream.get_length(), expected_length)
# Read them back and compare
for i in range(0,len(num_sizes)):
for j in range(0,num_writes):
n = bitstream.get_num(num_sizes[i])
self.assertEqual(n, nums[i][j])
def test_put_bit_dump_string_invalid_format(self):
"""
Test that put_bit_dump_string raises an exception when passed any
string not of the form ('0'|'1')*
"""
bitstream = BitStream()
# Try some fixed examples
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "23234")
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "Hello")
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "0101 0")
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "ｹｺｻｼｽ")
# Generate a random string conforming to ('0'|'1')* except for one
# (ascii) character.
num_bits = 50
pos_wrong_char = random.randint(1,48)
r_invalid_bit_string = ""
for i in range(0,pos_wrong_char):
r_invalid_bit_string += random.choice(('0','1'))
r_invalid_bit_string += \
random.choice(string.letters + "23456789_-/\\" + string.whitespace)
for i in range(0,num_bits - pos_wrong_char - 1):
r_invalid_bit_string += random.choice(('0','1'))
# Try the randomly generated example
self.assertRaises(ValueError, bitstream.put_bit_dump_string,
r_invalid_bit_string)
# Calls that throw exceptions should not alter the contents or position
# of the bitstream:
self.assertEquals(bitstream.get_length(),0)
self.assertEquals(bitstream.get_current_pos(),0)
def test_put_bit_dump_string_invalid_format(self):
"""
Test that put_bit_dump_string raises an exception when passed any
string not of the form ('0'|'1')*
"""
bitstream = BitStream()
# Try some fixed examples
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "23234")
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "Hello")
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "0101 0")
self.assertRaises(ValueError, bitstream.put_bit_dump_string, "ｹｺｻｼｽ")
# Generate a random string conforming to ('0'|'1')* except for one
# (ascii) character.
num_bits = 50
pos_wrong_char = random.randint(1, 48)
r_invalid_bit_string = ""
for i in range(0, pos_wrong_char):
r_invalid_bit_string += random.choice(('0', '1'))
r_invalid_bit_string += \
random.choice(string.letters + "23456789_-/\\" + string.whitespace)
for i in range(0, num_bits - pos_wrong_char - 1):
r_invalid_bit_string += random.choice(('0', '1'))
# Try the randomly generated example
self.assertRaises(ValueError, bitstream.put_bit_dump_string,
r_invalid_bit_string)
# Calls that throw exceptions should not alter the contents or position
# of the bitstream:
self.assertEquals(bitstream.get_length(), 0)
self.assertEquals(bitstream.get_current_pos(), 0)
def test_string_ascii(self):
"""
Test basic put_string and get_string behavior, using ASCII strings.
"""
bitstream = BitStream()
string1 = "Test string " # 12 chars/bytes
string2 = "using only ASCII characters (0-126):\n\t" # 38 chars/bytes
string3 = "Hello World!" # 12 chars/bytes
# Store our message in 3 writes
bitstream.put_string(string1)
bitstream.put_string(string2)
bitstream.put_string(string3)
# Sanity check:
self.assertEquals(bitstream.get_length(),(12+38+12)*8)
self.assertEquals(bitstream.get_current_pos(),(12+38+12)*8)
# Retrieve our message in 2 reads
bitstream.seek(0)
self.assertEquals(bitstream.get_string(29*8), # read 29 bytes
"Test string using only ASCII ")
self.assertEquals(bitstream.get_string(33*8), # read 33 bytes
"characters (0-126):\n\tHello World!")
def test_byte_basic(self):
"""
Test basic put_byte and get_byte behavior.
"""
bitstream = BitStream()
# Put a couple of bytes in the stream:
bytes = [
12, # 00001100
222, # 11011110
145, # 10010001
42, # 00101010
0, # 00000000
255
] # 11111111
for byte in bytes:
bitstream.put_byte(byte)
# Sanity check:
self.assertEquals(bitstream.get_length(), len(bytes) * 8)
self.assertEquals(bitstream.get_current_pos(), len(bytes) * 8)
# Read the bytes back from the stream
bitstream.seek(0)
for byte in bytes:
self.assertEquals(bitstream.get_byte(), byte)
# Read some bits from the stream, interpreting them as bytes, but
# without restricting ourselves to 8-bit aligned bytes
# e.g. read the "byte" defined by bits #4 to #12
bitstream.seek(4)
self.assertEquals(bitstream.get_byte(), 205) # 11001101
bitstream.seek(19)
self.assertEquals(bitstream.get_byte(), 137) # 10001001
def encrypt_bitstream(self, bitstream, pad_to=None, task_monitor=None):
"""
Encrypts the given bitstream into a ciphertext object.
Arguments:
bitstream::BitStream-- A stream of bits to encrypt
(see BitStream utility class).
pad_to::int -- Minimum size (in bytes) of the resulting
ciphertext. Data will be padded before
encryption to match this size.
task_monitor::TaskMonitor -- A task monitor for this task.
Returns:
ciphertext:Ciphertext -- A ciphertext object encapsulating the
encrypted data.
"""
random = StrongRandom()
## PART 1
# First, format the bitstream as per Ciphertext.py Note 001,
# previous to encryption.
# [size (64 bits) | message (size bits) | padding (X bits) ]
##
formated_bitstream = BitStream()
# The first 64 encode the size of the actual data in bits
SIZE_BLOCK_LENGTH = 64
size_in_bits = bitstream.get_length()
if(size_in_bits >= 2**SIZE_BLOCK_LENGTH):
raise ValueError("The size of the bitstream to encrypt is larger " \
"than 16 Exabits. The current format for " \
"PloneVote ciphertext only allows encrypting a " \
"maximum of 16 Exabits of information.")
formated_bitstream.put_num(size_in_bits, SIZE_BLOCK_LENGTH)
# We then copy the contents of the original bitstream
bitstream.seek(0)
formated_bitstream.put_bitstream_copy(bitstream)
# Finally, we append random data until we reach the desired pad_to
# length
unpadded_length = formated_bitstream.get_length()
if(pad_to != None and (pad_to * 8) > unpadded_length):
full_length = pad_to * 8
else:
full_length = unpadded_length
padding_left = full_length - unpadded_length
while(padding_left > 1024):
padding_bits = random.randint(1, 2**1024)
formated_bitstream.put_num(padding_bits,1024)
padding_left -= 1024
if(padding_left > 0):
padding_bits = random.randint(1, 2**padding_left)
formated_bitstream.put_num(padding_bits, padding_left)
padding_left = 0
## PART 2
# We encrypt the formated bitsteam using ElGamal into a Ciphertext
# object.
# See "Handbook of Applied Cryptography" Algorithm 8.18
##
# block_size is the size of each block of bits to encrypt
# since we can only encrypt messages in [0, p - 1]
# we should use (nbits - 1) as the block size, where
# 2**(nbits - 1) < p < 2**nbits
block_size = self.cryptosystem.get_nbits() - 1
prime = self.cryptosystem.get_prime()
generator = self.cryptosystem.get_generator()
# We pull data from the bitstream one block at a time and encrypt it
formated_bitstream.seek(0)
ciphertext = \
Ciphertext(self.cryptosystem.get_nbits(), self.get_fingerprint())
plaintext_bits_left = formated_bitstream.get_length()
# Check if we have a task monitor and register with it
if(task_monitor != None):
# We will do two tick()s per block to encrypt: one for generating
# the gamma component of the ciphertext block and another for the
# delta component (those are the two time intensive steps,
# because of exponentiation).
ticks = math.ceil((1.0 * plaintext_bits_left) / block_size) * 2
encrypt_task_mon = \
task_monitor.new_subtask("Encrypt data", expected_ticks = ticks)
while(plaintext_bits_left > 0):
# get next block (message, m, etc) to encrypt
if(plaintext_bits_left >= block_size):
block = formated_bitstream.get_num(block_size)
plaintext_bits_left -= block_size
else:
block = formated_bitstream.get_num(plaintext_bits_left)
# Encrypt as if the stream was filled with random data past its
# end, this avoids introducing a 0's gap during decryption to
# bitstream
displacement = block_size - plaintext_bits_left
block = block << displacement
padding = random.randint(0, 2**displacement - 1)
assert (padding // 2**displacement == 0), \
"padding should be at most displacement bits long"
block = block | padding
plaintext_bits_left = 0
# Select a random integer k, 1 <= k <= p − 2
k = random.randint(1, prime - 2)
# Compute gamma and delta
gamma = pow(generator, k, prime)
if(task_monitor != None): encrypt_task_mon.tick()
delta = (block * pow(self._key, k, prime)) % prime
if(task_monitor != None): encrypt_task_mon.tick()
# Add this encrypted data portion to the ciphertext object
ciphertext.append(gamma, delta)
# return the ciphertext object
return ciphertext
def from_file(cls, filename, SerializerClass=serialize.XMLSerializer):
"""
Loads an instance of Ciphertext from the given file.
Arguments:
filename::string -- The name of a file containing the ciphertext
in serialized form.
SerializerClass::class --
The class that provides the deserialization. XMLSerializer by
default. Must inherit from serialize.BaseSerializer and provide
an adequate deserialize_from_file method.
Note that often the same class used to serialize the data must
be used to deserialize it.
(see utilities/serialize.py documentation for more information)
Throws:
InvalidPloneVoteCryptoFileError -- If the file is not a valid
PloneVoteCryptoLib stored
ciphertext file.
"""
# Create a new serializer object for the Ciphertext structure definition
serializer = SerializerClass(Ciphertext_serialize_structure_definition)
# Deserialize the Ciphertext instance from file
try:
data = serializer.deserialize_from_file(filename)
except serialize.InvalidSerializeDataError as e:
# Convert the exception to an InvalidPloneVoteCryptoFileError
raise InvalidPloneVoteCryptoFileError(filename,
"File \"%s\" does not contain a valid ciphertext. The " \
"following error occurred while trying to deserialize the " \
"file contents: %s" % (filename, str(e)))
# Get the values from the deserialized data
try:
nbits = int(data["PloneVoteCiphertext"]["nbits"])
except ValueError:
raise InvalidPloneVoteCryptoFileError(filename,
"File \"%s\" does not contain a valid ciphertext. The " \
"stored value for nbits is not a valid (decimal) integer." \
% filename)
fingerprint_str = data["PloneVoteCiphertext"]["PKFingerprint"]
enc_data_str = data["PloneVoteCiphertext"]["EncryptedData"]
# Construct a new Ciphertext object with the given nbits and fingerprint
ciphertext = cls(nbits, fingerprint_str)
# Load the encrypted data
bitstream = BitStream()
bitstream.put_base64(enc_data_str)
bitstream.seek(0)
length = bitstream.get_length()
# number of gamma and delta blocks in the bitstream:
blocks = length // (nbits * 2)
for i in range(0, blocks):
gamma_val = bitstream.get_num(nbits)
delta_val = bitstream.get_num(nbits)
ciphertext.append(gamma_val, delta_val)
# Return the ciphertext
return ciphertext
def encrypt_bitstream(self, bitstream, pad_to=None, task_monitor=None):
"""
Encrypts the given bitstream into a ciphertext object.
Arguments:
bitstream::BitStream-- A stream of bits to encrypt
(see BitStream utility class).
pad_to::int -- Minimum size (in bytes) of the resulting
ciphertext. Data will be padded before
encryption to match this size.
task_monitor::TaskMonitor -- A task monitor for this task.
Returns:
ciphertext:Ciphertext -- A ciphertext object encapsulating the
encrypted data.
"""
random = StrongRandom()
## PART 1
# First, format the bitstream as per Ciphertext.py Note 001,
# previous to encryption.
# [size (64 bits) | message (size bits) | padding (X bits) ]
##
formated_bitstream = BitStream()
# The first 64 encode the size of the actual data in bits
SIZE_BLOCK_LENGTH = 64
size_in_bits = bitstream.get_length()
if(size_in_bits >= 2**SIZE_BLOCK_LENGTH):
raise ValueError("The size of the bitstream to encrypt is larger " \
"than 16 Exabits. The current format for " \
"PloneVote ciphertext only allows encrypting a " \
"maximum of 16 Exabits of information.")
formated_bitstream.put_num(size_in_bits, SIZE_BLOCK_LENGTH)
# We then copy the contents of the original bitstream
bitstream.seek(0)
formated_bitstream.put_bitstream_copy(bitstream)
# Finally, we append random data until we reach the desired pad_to
# length
unpadded_length = formated_bitstream.get_length()
if(pad_to != None and (pad_to * 8) > unpadded_length):
full_length = pad_to * 8
else:
full_length = unpadded_length
padding_left = full_length - unpadded_length
while(padding_left > 1024):
padding_bits = random.randint(1, 2**1024)
formated_bitstream.put_num(padding_bits,1024)
padding_left -= 1024
if(padding_left > 0):
padding_bits = random.randint(1, 2**padding_left)
formated_bitstream.put_num(padding_bits, padding_left)
padding_left = 0
## PART 2
# We encrypt the formated bitsteam using ElGamal into a Ciphertext
# object.
# See "Handbook of Applied Cryptography" Algorithm 8.18
##
# block_size is the size of each block of bits to encrypt
# since we can only encrypt messages in [0, p - 1]
# we should use (nbits - 1) as the block size, where
# 2**(nbits - 1) < p < 2**nbits
block_size = self.cryptosystem.get_nbits() - 1
prime = self.cryptosystem.get_prime()
generator = self.cryptosystem.get_generator()
# We pull data from the bitstream one block at a time and encrypt it
formated_bitstream.seek(0)
ciphertext = \
Ciphertext(self.cryptosystem.get_nbits(), self.get_fingerprint())
plaintext_bits_left = formated_bitstream.get_length()
# Check if we have a task monitor and register with it
if(task_monitor != None):
# We will do two tick()s per block to encrypt: one for generating
# the gamma component of the ciphertext block and another for the
# delta component (those are the two time intensive steps,
# because of exponentiation).
ticks = math.ceil((1.0 * plaintext_bits_left) / block_size) * 2
encrypt_task_mon = \
task_monitor.new_subtask("Encrypt data", expected_ticks = ticks)
while(plaintext_bits_left > 0):
# get next block (message, m, etc) to encrypt
if(plaintext_bits_left >= block_size):
block = formated_bitstream.get_num(block_size)
plaintext_bits_left -= block_size
else:
block = formated_bitstream.get_num(plaintext_bits_left)
# Encrypt as if the stream was filled with random data past its
# end, this avoids introducing a 0's gap during decryption to
# bitstream
displacement = block_size - plaintext_bits_left
block = block << displacement
padding = random.randint(0, 2**displacement - 1)
assert (padding / 2**displacement == 0), \
"padding should be at most displacement bits long"
block = block | padding
plaintext_bits_left = 0
# Select a random integer k, 1 <= k <= p − 2
k = random.randint(1, prime - 2)
# Compute gamma and delta
gamma = pow(generator, k, prime)
if(task_monitor != None): encrypt_task_mon.tick()
delta = (block * pow(self._key, k, prime)) % prime
if(task_monitor != None): encrypt_task_mon.tick()
# Add this encrypted data portion to the ciphertext object
ciphertext.append(gamma, delta)
# return the ciphertext object
return ciphertext