def _generate_random_integer_interval(self, minimum_value, maximum_value):
# sets the default minimum number of bits, even if the
# range is too small
minimum_number_bits = 32
# calculates the range of the random numbers
# to generate
range = maximum_value - minimum_value
# converts the range into bits
range_bits = math.log(range, 2)
# converts the range into bytes
range_bytes = colony.ceil_integer(range_bits / 8.0)
# converts the range into bits, but verifies that there
# is at least a minimum number of bits
range_bits = max(range_bytes * 8, minimum_number_bits * 2)
# generates the random number of bits to be used
number_bits = random.randint(minimum_number_bits, range_bits)
# generates the random integer with the number of bits generated
# and applying modulo of the range
random_base_value = self._generate_random_integer(number_bits) % range
# creates the random value adding the minimum value to the
# random base value
random_value = random_base_value + minimum_value
# returns the random value
return random_value
def _encrypt_string(self, message, key, modulus):
# retrieves the modulus size in bytes
modulus_size_bytes = colony.ceil_integer(math.log(modulus, 256))
# converts the message to integer, then uses this integer
# value to encrypt it using the rsa algorithm and converts
# the resulting encrypted integer back to a string
message_integer = self._string_to_integer(message)
message_integer_encrypted = self._encrypt_integer(message_integer, key, modulus)
message_encrypted = self._integer_to_string(message_integer_encrypted, modulus_size_bytes)
# returns the resulting message encrypted using the rsa
# algorithm for cryptographic purposes
return message_encrypted
def _randomized_primality_testing(self, number, k_value):
# the property of the jacobi witness function
q_value = 0.5
# calculates t to ha
t_value = colony.ceil_integer(k_value / math.log(1 / q_value, 2))
# iterates over the range of t value plus one
for _index in colony.legacy.xrange(t_value + 1):
# generates a random number in the interval
random_number = self._generate_random_integer_interval(1, number - 1)
# in case the random number is a jacobi witness
# then the number is not prime
if self._jacobi_witness(random_number, number):
# returns false (invalid)
return False
# returns true (valid)
return True
def _encrypt(self, keys, message):
# unpacks the keys tuple, retrieving the public key,
# private key and extras map and then retrieves the
# modulus from the public key
public_key, _private_key, _extras = keys
modulus = public_key["n"]
# calculates the size of the modulus in terms of bytes
# this will be used as the size of the message (including
# the padding)
modulus_size_bytes = colony.ceil_integer(math.log(modulus, 256))
# calculates the current size of the message and uses this
# value to calculate the size of the pad
message_length = len(message)
pad_length = modulus_size_bytes - message_length - 3
# creates the pad with the required size using just lower cased
# characters to avoid the zero value and then constructs the final
# padded message that includes the created padding
pad = "".join(random.choice(string.ascii_lowercase) for _value in colony.legacy.xrange(pad_length))
message_pad = b"\x00\x02" + colony.legacy.bytes(pad) + b"\x00" + message
return message_pad
def _generate_random_integer(self, number_bits):
"""
Generates a random integer of approximately the
size of the provided number bits bits rounded up
to whole bytes.
@type number_bits: int
@param number_bits: The number of bits of the generated
random integer.
@rtype: int
@return: The generated random integer.
"""
# calculates the number of bytes to represent the number
number_bytes = colony.ceil_integer(number_bits / 8.0)
# generates a random data string with the specified
# number of bytes in length
random_data = os.urandom(number_bytes)
# converts the random data int an integer
# vale and returns it to the caller method
random_integer = self._string_to_integer(random_data)
return random_integer
def _sign(self, keys, hash_algorithm_name, digest_value):
# retrieves the hash algorithm tuple
hash_algorithm_tuple = HASH_OBJECT_IDENTIFIERS_TUPLES_MAP[hash_algorithm_name]
# creates the ber structure
ber_structure = self.ber_plugin.create_structure({})
# creates the algorithm value
algorithm_value = {
TYPE_VALUE : OBJECT_IDENTIFIER_TYPE,
VALUE_VALUE : hash_algorithm_tuple
}
# creates the argument value
arguments_value = {
TYPE_VALUE : NULL_TYPE,
VALUE_VALUE : None
}
# creates the digest algorithm contents (list)
digest_algorithm_contents = [
algorithm_value,
arguments_value
]
# creates the digest algorithm
digest_algorithm = {
TYPE_VALUE : {
TYPE_CONSTRUCTED_VALUE : 1,
TYPE_NUMBER_VALUE : SEQUENCE_TYPE,
TYPE_CLASS_VALUE : 0
},
VALUE_VALUE : digest_algorithm_contents
}
# creates the digest value value
digest_value_value = {
TYPE_VALUE : OCTET_STRING_TYPE,
VALUE_VALUE : digest_value
}
# creates the signature value contents (list)
signature_value_contents = [
digest_algorithm,
digest_value_value
]
# creates the signature value
signature_value = {
TYPE_VALUE : {
TYPE_CONSTRUCTED_VALUE : 1,
TYPE_NUMBER_VALUE : SEQUENCE_TYPE,
TYPE_CLASS_VALUE : 0
},
VALUE_VALUE : signature_value_contents
}
# packs the signature value
signature_value_packed = ber_structure.pack(signature_value)
# creates the signature buffer
signature_buffer = colony.StringBuffer()
# unpacks the keys tuple, retrieving the
# public key, private key and extras map
public_key, _private_key, _extras = keys
# retrieves the modulus
modulus = public_key["n"]
# retrieves the signature value packed length
signature_value_packed_length = len(signature_value_packed)
# retrieves the modulus size in bytes
modulus_size_bytes = colony.ceil_integer(math.log(modulus, 256))
# calculates the padding size (from the modulus size bytes and the signature value packed length)
padding_size = modulus_size_bytes - (signature_value_packed_length + 3)
# writes the beginning of the padding value to the signature buffer
signature_buffer.write(b"\x00")
signature_buffer.write(b"\x01")
# creates the padding string value
padding = b"\xff" * padding_size
# writes the padding to the signature buffer
signature_buffer.write(padding)
# writes the end of padding value to the signature buffer
signature_buffer.write(b"\x00")
# writes the signature value packed in the string buffer
signature_buffer.write(signature_value_packed)
# retrieves the signature verified from the string buffer
signature_verified = signature_buffer.get_value()
# returns the signature verified
return signature_verified
