def inner_product(cypher1, cypher2):
# We also set up an Encryptor, Evaluator, and Decryptor here.
evaluator = Evaluator(context)
decryptor = Decryptor(context, secret_key)
for i in range(len(cypher1)):
evaluator.multiply(cypher1[i], cypher2[i])
encrypted_result = Ciphertext()
evaluator.add_many(cypher1, encrypted_result)
return encrypted_result
def dot_product():
print("Example: Weighted Average")
# In this example we demonstrate the FractionalEncoder, and use it to compute
# a weighted average of 10 encrypted rational numbers. In this computation we
# perform homomorphic multiplications of ciphertexts by plaintexts, which is
# much faster than regular multiplications of ciphertexts by ciphertexts.
# Moreover, such `plain multiplications' never increase the ciphertext size,
# which is why we have no need for evaluation keys in this example.
# We start by creating encryption parameters, setting up the SEALContext, keys,
# and other relevant objects. Since our computation has multiplicative depth of
# only two, it suffices to use a small poly_modulus.
parms = EncryptionParameters()
parms.set_poly_modulus("1x^2048 + 1")
parms.set_coeff_modulus(seal.coeff_modulus_128(2048))
parms.set_plain_modulus(1 << 8)
context = SEALContext(parms)
print_parameters(context)
keygen = KeyGenerator(context)
keygen2 = KeyGenerator(context)
public_key = keygen.public_key()
secret_key = keygen.secret_key()
secret_key2 = keygen.secret_key()
# We also set up an Encryptor, Evaluator, and Decryptor here.
encryptor = Encryptor(context, public_key)
evaluator = Evaluator(context)
decryptor = Decryptor(context, secret_key2)
# Create a vector of 10 rational numbers (as doubles).
# rational_numbers = [3.1, 4.159, 2.65, 3.5897, 9.3, 2.3, 8.46, 2.64, 3.383, 2.795]
rational_numbers = np.random.rand(10)
# Create a vector of weights.
# coefficients = [0.1, 0.05, 0.05, 0.2, 0.05, 0.3, 0.1, 0.025, 0.075, 0.05]
coefficients = np.random.rand(10)
my_result = np.dot(rational_numbers, coefficients)
# We need a FractionalEncoder to encode the rational numbers into plaintext
# polynomials. In this case we decide to reserve 64 coefficients of the
# polynomial for the integral part (low-degree terms) and expand the fractional
# part to 32 digits of precision (in base 3) (high-degree terms). These numbers
# can be changed according to the precision that is needed; note that these
# choices leave a lot of unused space in the 2048-coefficient polynomials.
encoder = FractionalEncoder(context.plain_modulus(), context.poly_modulus(), 64, 32, 3)
# We create a vector of ciphertexts for encrypting the rational numbers.
encrypted_rationals = []
rational_numbers_string = "Encoding and encrypting: "
for i in range(10):
# We create our Ciphertext objects into the vector by passing the
# encryption parameters as an argument to the constructor. This ensures
# that enough memory is allocated for a size 2 ciphertext. In this example
# our ciphertexts never grow in size (plain multiplication does not cause
# ciphertext growth), so we can expect the ciphertexts to remain in the same
# location in memory throughout the computation. In more complicated examples
# one might want to call a constructor that reserves enough memory for the
# ciphertext to grow to a specified size to avoid costly memory moves when
# multiplications and relinearizations are performed.
encrypted_rationals.append(Ciphertext(parms))
encryptor.encrypt(encoder.encode(rational_numbers[i]), encrypted_rationals[i])
rational_numbers_string += (str)(rational_numbers[i])[:6]
if i < 9: rational_numbers_string += ", "
print(rational_numbers_string)
# Next we encode the coefficients. There is no reason to encrypt these since they
# are not private data.
encoded_coefficients = []
encoded_coefficients_string = "Encoding plaintext coefficients: "
encrypted_coefficients =[]
for i in range(10):
encoded_coefficients.append(encoder.encode(coefficients[i]))
encrypted_coefficients.append(Ciphertext(parms))
encryptor.encrypt(encoded_coefficients[i], encrypted_coefficients[i])
encoded_coefficients_string += (str)(coefficients[i])[:6]
if i < 9: encoded_coefficients_string += ", "
print(encoded_coefficients_string)
# We also need to encode 0.1. Multiplication by this plaintext will have the
# effect of dividing by 10. Note that in SEAL it is impossible to divide
# ciphertext by another ciphertext, but in this way division by a plaintext is
# possible.
div_by_ten = encoder.encode(0.1)
# Now compute each multiplication.
prod_result = [Ciphertext() for i in range(10)]
prod_result2 = [Ciphertext() for i in range(10)]
print("Computing products: ")
for i in range(10):
# Note how we use plain multiplication instead of usual multiplication. The
# result overwrites the first argument in the function call.
evaluator.multiply_plain(encrypted_rationals[i], encoded_coefficients[i], prod_result[i])
evaluator.multiply(encrypted_rationals[i], encrypted_coefficients[i], prod_result2[i])
print("Done")
# To obtain the linear sum we need to still compute the sum of the ciphertexts
# in encrypted_rationals. There is an easy way to add together a vector of
# Ciphertexts.
encrypted_result = Ciphertext()
encrypted_result2 = Ciphertext()
print("Adding up all 10 ciphertexts: ")
evaluator.add_many(prod_result, encrypted_result)
evaluator.add_many(prod_result2, encrypted_result2)
print("Done")
# Perform division by 10 by plain multiplication with div_by_ten.
# print("Dividing by 10: ")
# evaluator.multiply_plain(encrypted_result, div_by_ten)
# print("Done")
# How much noise budget do we have left?
print("Noise budget in result: " + (str)(decryptor.invariant_noise_budget(encrypted_result)) + " bits")
# Decrypt, decode, and print result.
plain_result = Plaintext()
plain_result2 = Plaintext()
print("Decrypting result: ")
decryptor.decrypt(encrypted_result, plain_result)
decryptor.decrypt(encrypted_result2, plain_result2)
print("Done")
result = encoder.decode(plain_result)
print("Weighted average: " + (str)(result)[:8])
result2 = encoder.decode(plain_result2)
print("Weighted average: " + (str)(result2)[:8])
print('\n\n', my_result)
class CipherMatrix:
"""
"""
def __init__(self, matrix=None):
"""
:param matrix: numpy.ndarray to be encrypted.
"""
self.parms = EncryptionParameters()
self.parms.set_poly_modulus("1x^2048 + 1")
self.parms.set_coeff_modulus(seal.coeff_modulus_128(2048))
self.parms.set_plain_modulus(1 << 8)
self.context = SEALContext(self.parms)
# self.encoder = IntegerEncoder(self.context.plain_modulus())
self.encoder = FractionalEncoder(self.context.plain_modulus(),
self.context.poly_modulus(), 64, 32,
3)
self.keygen = KeyGenerator(self.context)
self.public_key = self.keygen.public_key()
self.secret_key = self.keygen.secret_key()
self.encryptor = Encryptor(self.context, self.public_key)
self.decryptor = Decryptor(self.context, self.secret_key)
self.evaluator = Evaluator(self.context)
self._saved = False
self._encrypted = False
self._id = '{0:04d}'.format(np.random.randint(1000))
if matrix is not None:
assert len(
matrix.shape) == 2, "Only 2D numpy matrices accepted currently"
self.matrix = np.copy(matrix)
self.encrypted_matrix = np.empty(self.matrix.shape, dtype=object)
for i in range(self.matrix.shape[0]):
for j in range(self.matrix.shape[1]):
self.encrypted_matrix[i, j] = Ciphertext()
else:
self.matrix = None
self.encrypted_matrix = None
print(self._id, "Created")
def __repr__(self):
"""
:return:
"""
print("Encrypted:", self._encrypted)
if not self._encrypted:
print(self.matrix)
return ""
else:
return '[]'
def __str__(self):
"""
:return:
"""
print("| Encryption parameters:")
print("| poly_modulus: " + self.context.poly_modulus().to_string())
# Print the size of the true (product) coefficient modulus
print("| coeff_modulus_size: " + (
str)(self.context.total_coeff_modulus().significant_bit_count()) +
" bits")
print("| plain_modulus: " +
(str)(self.context.plain_modulus().value()))
print("| noise_standard_deviation: " +
(str)(self.context.noise_standard_deviation()))
if self.matrix is not None:
print(self.matrix.shape)
return str(type(self))
def __add__(self, other):
"""
:param other:
:return:
"""
assert isinstance(
other, CipherMatrix), "Can only be added with a CipherMatrix"
A_enc = self._encrypted
B_enc = other._encrypted
if A_enc:
A = self.encrypted_matrix
else:
A = self.matrix
if B_enc:
B = other.encrypted_matrix
else:
B = other.matrix
assert A.shape == B.shape, "Dimension mismatch, Matrices must be of same shape. Got {} and {}".format(
A.shape, B.shape)
shape = A.shape
result = CipherMatrix(np.zeros(shape, dtype=np.int32))
result._update_cryptors(self.get_keygen())
if A_enc:
if B_enc:
res_mat = result.encrypted_matrix
for i in range(shape[0]):
for j in range(shape[1]):
self.evaluator.add(A[i, j], B[i, j], res_mat[i, j])
result._encrypted = True
else:
res_mat = result.encrypted_matrix
for i in range(shape[0]):
for j in range(shape[1]):
self.evaluator.add_plain(A[i, j],
self.encoder.encode(B[i, j]),
res_mat[i, j])
result._encrypted = True
else:
if B_enc:
res_mat = result.encrypted_matrix
for i in range(shape[0]):
for j in range(shape[1]):
self.evaluator.add_plain(B[i, j],
self.encoder.encode(A[i, j]),
res_mat[i, j])
result._encrypted = True
else:
result.matrix = A + B
result._encrypted = False
return result
def __sub__(self, other):
"""
:param other:
:return:
"""
assert isinstance(other, CipherMatrix)
if other._encrypted:
shape = other.encrypted_matrix.shape
for i in range(shape[0]):
for j in range(shape[1]):
self.evaluator.negate(other.encrypted_matrix[i, j])
else:
other.matrix = -1 * other.matrix
return self + other
def __mul__(self, other):
"""
:param other:
:return:
"""
assert isinstance(
other, CipherMatrix), "Can only be multiplied with a CipherMatrix"
# print("LHS", self._id, "RHS", other._id)
A_enc = self._encrypted
B_enc = other._encrypted
if A_enc:
A = self.encrypted_matrix
else:
A = self.matrix
if B_enc:
B = other.encrypted_matrix
else:
B = other.matrix
Ashape = A.shape
Bshape = B.shape
assert Ashape[1] == Bshape[0], "Dimensionality mismatch"
result_shape = [Ashape[0], Bshape[1]]
result = CipherMatrix(np.zeros(shape=result_shape))
if A_enc:
if B_enc:
for i in range(Ashape[0]):
for j in range(Bshape[1]):
result_array = []
for k in range(Ashape[1]):
res = Ciphertext()
self.evaluator.multiply(A[i, k], B[k, j], res)
result_array.append(res)
self.evaluator.add_many(result_array,
result.encrypted_matrix[i, j])
result._encrypted = True
else:
for i in range(Ashape[0]):
for j in range(Bshape[1]):
result_array = []
for k in range(Ashape[1]):
res = Ciphertext()
self.evaluator.multiply_plain(
A[i, k], self.encoder.encode(B[k, j]), res)
result_array.append(res)
self.evaluator.add_many(result_array,
result.encrypted_matrix[i, j])
result._encrypted = True
else:
if B_enc:
for i in range(Ashape[0]):
for j in range(Bshape[1]):
result_array = []
for k in range(Ashape[1]):
res = Ciphertext()
self.evaluator.multiply_plain(
B[i, k], self.encoder.encode(A[k, j]), res)
result_array.append(res)
self.evaluator.add_many(result_array,
result.encrypted_matrix[i, j])
result._encrypted = True
else:
result.matrix = np.matmul(A, B)
result._encrypted = False
return result
def save(self, path):
"""
:param path:
:return:
"""
save_dir = os.path.join(path, self._id)
if self._saved:
print("CipherMatrix already saved")
else:
assert not os.path.isdir(save_dir), "Directory already exists"
os.mkdir(save_dir)
if not self._encrypted:
self.encrypt()
shape = self.encrypted_matrix.shape
for i in range(shape[0]):
for j in range(shape[1]):
element_name = str(i) + '-' + str(j) + '.ahem'
self.encrypted_matrix[i, j].save(
os.path.join(save_dir, element_name))
self.secret_key.save("/keys/" + "." + self._id + '.wheskey')
self._saved = True
return save_dir
def load(self, path, load_secret_key=False):
"""
:param path:
:param load_secret_key:
:return:
"""
self._id = path.split('/')[-1]
print("Loading Matrix:", self._id)
file_list = os.listdir(path)
index_list = [[file.split('.')[0].split('-'), file]
for file in file_list]
M = int(max([int(ind[0][0]) for ind in index_list])) + 1
N = int(max([int(ind[0][1]) for ind in index_list])) + 1
del self.encrypted_matrix
self.encrypted_matrix = np.empty([M, N], dtype=object)
for index in index_list:
i = int(index[0][0])
j = int(index[0][1])
self.encrypted_matrix[i, j] = Ciphertext()
self.encrypted_matrix[i, j].load(os.path.join(path, index[1]))
if load_secret_key:
self.secret_key.load("/keys/" + "." + self._id + '.wheskey')
self.matrix = np.empty(self.encrypted_matrix.shape)
self._encrypted = True
def encrypt(self, matrix=None, keygen=None):
"""
:param matrix:
:return:
"""
assert not self._encrypted, "Matrix already encrypted"
if matrix is not None:
assert self.matrix is None, "matrix already exists"
self.matrix = np.copy(matrix)
shape = self.matrix.shape
self.encrypted_matrix = np.empty(shape, dtype=object)
if keygen is not None:
self._update_cryptors(keygen)
for i in range(shape[0]):
for j in range(shape[1]):
val = self.encoder.encode(self.matrix[i, j])
self.encrypted_matrix[i, j] = Ciphertext()
self.encryptor.encrypt(val, self.encrypted_matrix[i, j])
self._encrypted = True
def decrypt(self, encrypted_matrix=None, keygen=None):
"""
:return:
"""
if encrypted_matrix is not None:
self.encrypted_matrix = encrypted_matrix
assert self._encrypted, "No encrypted matrix"
del self.matrix
shape = self.encrypted_matrix.shape
self.matrix = np.empty(shape)
if keygen is not None:
self._update_cryptors(keygen)
for i in range(shape[0]):
for j in range(shape[1]):
plain_text = Plaintext()
self.decryptor.decrypt(self.encrypted_matrix[i, j], plain_text)
self.matrix[i, j] = self.encoder.decode(plain_text)
self._encrypted = False
return np.copy(self.matrix)
def get_keygen(self):
"""
:return:
"""
return self.keygen
def _update_cryptors(self, keygen):
"""
:param keygen:
:return:
"""
self.keygen = keygen
self.public_key = keygen.public_key()
self.secret_key = keygen.secret_key()
self.encryptor = Encryptor(self.context, self.public_key)
self.decryptor = Decryptor(self.context, self.secret_key)
return
class FHECryptoEngine(CryptoEngine):
def __init__(self):
CryptoEngine.__init__(self, defs.ENC_MODE_FHE)
self.log_id = 'FHECryptoEngine'
self.encrypt_params = None
self.context = None
self.encryptor = None
self.evaluator = None
self.decryptor = None
return
def load_keys(self):
self.private_key = SecretKey()
self.private_key.load(defs.FN_FHE_PRIVATE_KEY)
self.public_key = PublicKey()
self.public_key.load(defs.FN_FHE_PUBLIC_KEY)
return True
def generate_keys(self):
if self.encrypt_params == None or \
self.context == None:
self.init_encrypt_params()
keygen = KeyGenerator(self.context)
# Generate the private key
self.private_key = keygen.secret_key()
self.private_key.save(defs.FN_FHE_PRIVATE_KEY)
# Generate the public key
self.public_key = keygen.public_key()
self.public_key.save(defs.FN_FHE_PUBLIC_KEY)
return True
def init_encrypt_params(self):
self.encrypt_params = EncryptionParameters()
self.encrypt_params.set_poly_modulus("1x^2048 + 1")
self.encrypt_params.set_coeff_modulus(seal.coeff_modulus_128(2048))
self.encrypt_params.set_plain_modulus(1 << 8)
self.context = SEALContext(self.encrypt_params)
return
def initialize(self, use_old_keys=False):
# Initialize encryption params
self.init_encrypt_params()
# Check if the public & private key files exist
if os.path.isfile(defs.FN_FHE_PUBLIC_KEY) and \
os.path.isfile(defs.FN_FHE_PRIVATE_KEY) and \
use_old_keys == True:
self.log("Keys already exist. Reusing them instead.")
if not self.load_keys():
self.log("Failed to load keys")
return False
else:
# If not, then attempt to generate new ones
if not self.generate_keys():
self.log("Failed to generate keys")
return False
# Setup the rest of the crypto engine
self.encryptor = Encryptor(self.context, self.public_key)
self.evaluator = Evaluator(self.context)
self.decryptor = Decryptor(self.context, self.private_key)
# Set the initialized flag
self.initialized = True
return True
def encrypt(self, data):
if not self.initialized:
self.log("Not initialized")
return False
# Setup the encoder
encoder = FractionalEncoder(self.context.plain_modulus(), self.context.poly_modulus(), 64, 32, 3)
# Create the array of encrypted data objects
encrypted_data = []
for raw_data in data:
encrypted_data.append(Ciphertext(self.encrypt_params))
self.encryptor.encrypt( encoder.encode(raw_data), encrypted_data[-1] )
# Pickle each Ciphertext, base64 encode it, and store it in the array
for i in range(0, len(encrypted_data)):
encrypted_data[i].save("fhe_enc.bin")
encrypted_data[i] = base64.b64encode( pickle.dumps(encrypted_data[i]) )
return encrypted_data
def evaluate(self, encrypted_data, lower_idx=0, higher_idx=-1):
result = Ciphertext()
# Setup the encoder
encoder = FractionalEncoder(self.context.plain_modulus(), self.context.poly_modulus(), 64, 32, 3)
# Unpack the data first
unpacked_data = []
for d in encrypted_data[lower_idx:higher_idx]:
unpacked_data.append(pickle.loads(base64.b64decode(d)))
# Perform operations
self.evaluator.add_many(unpacked_data, result)
div = encoder.encode(1/len(unpacked_data))
self.evaluator.multiply_plain(result, div)
# Pack the result
result = base64.b64encode( pickle.dumps(result) )
return result
def decrypt(self, raw_data):
if not self.initialized:
self.log("Not initialized")
return False
# Setup the encoder
encoder = FractionalEncoder(self.context.plain_modulus(), self.context.poly_modulus(), 64, 32, 3)
# Unpickle, base64 decode, and decrypt each ciphertext result
decrypted_data = []
for d in raw_data:
encrypted_data = pickle.loads( base64.b64decode(d) )
plain_data = Plaintext()
self.decryptor.decrypt(encrypted_data, plain_data)
decrypted_data.append( str(encoder.decode(plain_data)) )
return decrypted_data
