Pyfhel ¶

add_plain(self, PyCtxt ctxt, PyPtxt ptxt, bool in_new_ctxt=False) → PyCtxt¶

Sum a PyCtxt ciphertext and a PyPtxt plaintext.

Sums a ciphertext and a plaintext. Encoding must be the same. Requiressame context and encryption with same public key. The result is applied to the first ciphertext.

Parameters:

ctxt (PyCtxt) – ciphertext whose values are added with ptxt.
ptxt (PyPtxt) – plaintext left untouched.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

align_mod_n_scale(self, PyCtxt this: PyCtxt, other: Union[PyCtxt, PyPtxt], bool copy_this: bool = True, bool copy_other: bool = True, bool only_mod: bool = False) → Tuple[PyCtxt, PyCtxt | PyPtxt]¶

Aligns the scales & mod_levels of this and other.

Only applies to CKKS. Alligns the scales of the this ciphertext and the other ciphertext/plaintext by aligning the scale and mod_level: - Rescales the ciphertext with the highest mod_level to the next qi/s - Mod switches the second ciphertext/plaintext to the next qi/s - At the end, rounds the scale of the rescaled ciphertext

Parameters:

this (PyCtxt) – Ciphertext to align.
other (PyCtxt|PyPtxt) – Ciphertext|plaintext to align with.
copy_this (bool) – Copy the this ciphertext before aligning.
copy_other (bool) – Copy the other ciphertext|plaintext before aligning.
only_mod (bool) – If True, only mod_level is aligned.

Returns:

inputs with aligned scale & mod_level.

Return type:

Tuple[PyCtxt, Union[PyCtxt, PyPtxt]]

batchEnabled(self) → bool¶

Flag of batch enabled.

Returns:: Result, True if enabled, False if disabled.
Return type:: bool

contextGen(self, unicode scheme, int n, int t_bits=0, int64_t t=0, int sec=128, double scale=1, int scale_bits=0, vector[int] qi_sizes={}, vector[uint64_t] qi={}) → string¶

Generates Homomorphic Encryption context based on parameters.

Creates a HE context based in parameters, as well as an appropriate encoder according to the scheme choice. The HE context contains the “public parameters” of the scheme, required for all operations (encryption/decryption, scheme/decoding, operations). Validates the choice of parameters and returns the validation status/error.

BFV scheme: vectorized integer operations in Single Instruction Multiple: Data (SIMD) fashion. The scheme requires a plain_modulus t prime, with t-1 being multiple of 2*n (n is the polynomial modulus degree). This is generated automatically with bitsize t_bits, and it will serve as plaintext modulo (the maximum value of plaintext/ciphetext slots). The coefficient moduli (qi) is chosen under the hood with the security level sec, based on homomorphicencryption.org, although it can be set manually with qi_sizes|qi.

BGV scheme: TODO

CKKS scheme: vectorized approximate fixed point operations in SIMD. The: underlying coefficient modulus (q) is set with a list of prime sizes qi_sizes (bit sizes) or directly with a chain of primes (qi).

A larger coeff_modulus (q = prod(qi)) implies a larger noise budget, hence more encrypted computation capabilities. However, an upper bound for the total bit-length (total_coeff_modulus_bit_count) of the coeff_modulus is determined by the poly_modulus_degree (n), as follows:

poly_modulus_degree \| max coeff_modulus bit-length
1024 2048 4096 8192 16384 32768	27 54 109 218 438 881

Parameters:

scheme (str) – HE scheme (“bfv” or “ckks”, for integer or float ops).
n (int) – Polynomial coefficient modulus m. (Poly: 1*x^n+1), directly linked to the multiplication depth, (SEAL’s poly_modulus_degree) and equal to the number of slots (nSlots) in bfv.
qi (int, optional) – Chain of primes composing the coefficient moduli. Overriden by qi if scheme is “ckks” and sec if scheme is “bfv”.
qi_sizes (list of ints, optional) – Chain of prime sizes (#bits), to set q.
sec (int, optional) – Security level equivalent in AES. One of {0 (unset)128, 192, 256}. There is little reason to go beyond 128 bits. Sets q if scheme is “bfv” (overriding qi|qi_sizes), and adds compliance checks for “ckks”.
-- (-- Only for CKKS scheme) –
t_bits (int, optional) – Plaintext modulus bit size. Overrides t.
t (int, optional) – Plaintext modulus. (SEAL’s plain_modulus)
-- –
scale (int, optional) – Upscale factor for fixed-point values.
scale_bits (int, optional) – overrides scale, sets it to 2**scale_bits.

Returns:

The result of validating the chosen parameters. Contains:: ’success: valid’ if the parameters are valid. An informing error name and message otherwise.

Return type:

str

cumul_add(self, PyCtxt ctxt, bool in_new_ctxt=False, size_t n_elements=0) → PyCtxt¶

Performs cumulative addition over the first n_elements of a PyCtxt.

Runs log2(n_elements) additions and rotations to obtain the cumulative sum in the first element of the result. For correct results use a power of 2 for n_elements. If n_elements is 0, it will use the size (nSlots) of the ciphertext.

Parameters:

ctxt (PyCtxt) – ciphertext whose values are rotated.
n_elements (int) – number of elements to rotate. If 0, uses the ciphertext’s nSlots.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

decode(self, PyPtxt ptxt)¶

Decodes any valid PyPtxt into a value or vector.

Decodes a PyPtxt plaintext based on the current context. Outputs an integer (int), a truncated decimal (float), or in Batch mode a 1D vector of integers. Automatically selects the decoding function based on type.

Parameters:: ptxt (PyPtxt, int, float, np.array) – plaintext to decode.
Returns:: the decoded value or vector.
Return type:: int, float, list[int]
Raises:: TypeError – if the plaintext doesn’t have a valid type.

decodeABGV(self, PyPtxt[:] ptxt) → ndarray¶

decodeAComplex(self, PyPtxt[:] ptxt) → ndarray¶

decodeAFrac(self, PyPtxt[:] ptxt) → ndarray¶

decodeAInt(self, PyPtxt[:] ptxt) → ndarray¶

decodeBGV(self, PyPtxt ptxt) → ndarray¶

Decodes a PyPtxt plaintext into a single int value. Decodes a PyPtxt plaintext into a single int value based on the current context. PyPtxt scheme must be bgv. :param ptxt: plaintext to decode. :type ptxt: PyPtxt, optional

Returns:: the decoded integer value
Return type:: int
Raises:: RuntimeError – if the ciphertext scheme isn’t Scheme_t.bgv

decodeComplex(self, PyPtxt ptxt) → ndarray¶

Decodes a PyPtxt plaintext into a single float value.

Decodes a PyPtxt plaintext into a single float value based on the current context. PyPtxt scheme must be ckks.

Parameters:: ptxt (PyPtxt) – plaintext to decode.
Returns:: the decoded float value
Return type:: float
Raises:: RuntimeError – if the ciphertext scheme isn’t Scheme_t.ckks

decodeFrac(self, PyPtxt ptxt) → ndarray¶

Decodes a PyPtxt plaintext into a single float value.

Decodes a PyPtxt plaintext into a single float value based on the current context. PyPtxt scheme must be ckks.

Parameters:: ptxt (PyPtxt) – plaintext to decode.
Returns:: the decoded float value
Return type:: float
Raises:: RuntimeError – if the ciphertext scheme isn’t Scheme_t.ckks

decodeInt(self, PyPtxt ptxt) → ndarray¶

Decodes a PyPtxt plaintext into a single int value.

Decodes a PyPtxt plaintext into a single int value based on the current context. PyPtxt scheme must be bfv.

Parameters:: ptxt (PyPtxt, optional) – plaintext to decode.
Returns:: the decoded integer value
Return type:: int
Raises:: RuntimeError – if the ciphertext scheme isn’t Scheme_t.bfv

decrypt(self, PyCtxt ctxt, bool decode=True, PyPtxt ptxt=None)¶

Decrypts any valid PyCtxt into either a PyPtxt ciphertext or a value.

Decrypts a PyCtxt ciphertext using the current secret key, based on the current context. Outputs an integer (int), a truncated decimal (float), a PyPtxt encoded plaintext, or in Batch mode a 1D numpy vector of integers. Can also return a PyPtxt by setting decode to True.

Selects the encryption function based on type.

If provided a plaintext, decrypts the ciphertext inside it.

Parameters:

ctxt (PyCtxt) – ciphertext to decrypt.
(bool (decode) – True): return value or return PyPtxt.
ptxt (PyPtxt, optional) – Optional destination PyPtxt.

Returns:

the decrypted result

Return type:

PyPtxt, np.array[int|float]

Raises:

TypeError – if the cipertext scheme is invalid.

decryptABGV(self, PyCtxt ctxt) → ndarray¶

decryptAComplex(self, PyCtxt ctxt) → ndarray¶

decryptAFrac(self, PyCtxt ctxt) → ndarray¶

decryptAInt(self, PyCtxt ctxt) → ndarray¶

decryptAPtxt(self, PyCtxt ctxt) → ndarray¶

decryptBGV(self, PyCtxt ctxt) → ndarray¶

Decrypts a PyCtxt ciphertext into a single int value. Decrypts a PyCtxt ciphertext using the current secret key, based on the current context. PyCtxt scheme must be bfv. :param ctxt: ciphertext to decrypt. :type ctxt: PyCtxt, optional

Returns:: the decrypted integer value
Return type:: int
Raises:: RuntimeError – if the ctxt scheme isn’t Scheme_t.bgv

decryptComplex(self, PyCtxt ctxt) → ndarray¶

Decrypts a PyCtxt ciphertext into a vector of complex values

Decrypts a PyCtxt ciphertext using the current secret key, based on the current context. PyCtxt scheme must be ckks.

Parameters:: ctxt (PyCtxt, optional) – ciphertext to decrypt.
Returns:: the decrypted complex vector
Return type:: np.array[complex]
Raises:: RuntimeError – if the ctxt scheme isn’t Scheme_t.ckks

decryptFrac(self, PyCtxt ctxt) → ndarray¶

Decrypts a PyCtxt ciphertext into a vector of floats

Decrypts a PyCtxt ciphertext using the current secret key, based on the current context. PyCtxt scheme must be ckks.

Parameters:: ctxt (PyCtxt, optional) – ciphertext to decrypt.
Returns:: the decrypted float vector
Return type:: np.array[float]
Raises:: RuntimeError – if the ctxt scheme isn’t Scheme_t.ckks

decryptInt(self, PyCtxt ctxt) → ndarray¶

Decrypts a PyCtxt ciphertext into a single int value.

Decrypts a PyCtxt ciphertext using the current secret key, based on the current context. PyCtxt scheme must be bfv.

Parameters:: ctxt (PyCtxt, optional) – ciphertext to decrypt.
Returns:: the decrypted integer value
Return type:: int
Raises:: RuntimeError – if the ctxt scheme isn’t Scheme_t.bfv

decryptPtxt(self, PyCtxt ctxt, PyPtxt ptxt=None) → PyPtxt¶

Decrypts a PyCtxt ciphertext into a PyPtxt plaintext.

Decrypts a PyCtxt ciphertext using the current secret key, based on the current context. No regard to scheme (decode PyPtxt to obtain value).

Parameters:

ctxt (PyCtxt) – ciphertext to decrypt.
ptxt (PyPtxt, optional) – Optional destination plaintext.

Returns:

the decrypted plaintext

Return type:

empty_poly(self, PyCtxt ref) → PyPoly¶: Generates an empty polynomial using ref as reference

encode(self, val_vec, double scale=0, int scale_bits=0, PyPtxt ptxt=None)¶

Encodes any valid value/vector into a PyPtxt plaintext.

Encodes any valid value/vector based on the current context. Value/Vector must be an integer (int), a decimal that will get truncated (float), or in Batch mode a 1D vector of integers.

If provided a plaintext, encodes the vector inside it.

Parameters:

val_vec (int, float, list[int]) – value/vector to encode.
ptxt (PyPtxt, optional) – Optional destination plaintext.

Returns:

the plaintext containing the encoded vector.

Return type:

Raises:

TypeError – if the val_vec doesn’t have a valid type.

encodeABGV(self, int64_t[:, ::1] arr) → ndarray¶

encodeAComplex(self, double complex[:, ::1] arr, double scale=0, int scale_bits=0) → ndarray¶

encodeAFrac(self, double[:, ::1] arr, double scale=0, int scale_bits=0) → ndarray¶

encodeAInt(self, int64_t[:, ::1] arr) → ndarray¶

encodeBGV(self, int64_t[::1] arr, PyPtxt ptxt=None) → PyPtxt¶

Encodes an integer vector into a PyPtxt plaintext. Encodes a vector of integer values based on the current context. If provided a plaintext, encodes the values inside it. :param arr: values to encode. :type arr: np.array[int]

Returns:: the plaintext containing the encoded values
Return type:: PyPtxt

encodeComplex(self, double complex[::1] arr, PyPtxt ptxt=None, double scale=0, int scale_bits=0) → PyPtxt¶

Encodes a complex vector into a PyPtxt plaintext.

Encodes a vector of complex values based on the current context. If provided a plaintext, encodes the values inside it.

Parameters:

arr (np.array[complex]) – values to encode.
ptxt (PyPtxt, optional) – Optional destination plaintext.

Returns:

the plaintext containing the encoded values

Return type:

encodeFrac(self, double[::1] arr, PyPtxt ptxt=None, double scale=0, int scale_bits=0) → PyPtxt¶

Encodes a float vector into a PyPtxt plaintext.

Encodes a vector of float values based on the current context. If provided a plaintext, encodes the values inside it.

Parameters:

arr (np.array[float]) – values to encode.
ptxt (PyPtxt, optional) – Optional destination plaintext.

Returns:

the plaintext containing the encoded values

Return type:

encodeInt(self, int64_t[::1] arr, PyPtxt ptxt=None) → PyPtxt¶

Encodes an integer vector into a PyPtxt plaintext.

Encodes a vector of integer values based on the current context. If provided a plaintext, encodes the values inside it.

Parameters:: arr (np.array[int]) – values to encode.
Returns:: the plaintext containing the encoded values
Return type:: PyPtxt

encrypt(self, ptxt, PyCtxt ctxt=None, scale=None)¶

Encrypts any valid value into a PyCtxt ciphertext.

Encrypts a plaintext using the current secret key, based on the current context. Plaintext must be an integer vector (int), a float vector that will get truncated (double), or a PyPtxt encoded plaintext. Selects the encryption function based on type.

If provided a ciphertext, encrypts the plaintext inside it.

Parameters:

ptxt (PyPtxt, int, double, np.ndarray) – plaintext to encrypt.
ctxt (PyCtxt, optional) – Optional destination ciphertext.

Returns:

the ciphertext containing the encrypted plaintext

Return type:

Raises:

TypeError – if the plaintext doesn’t have a valid type.

encryptABGV(self, int64_t[:, ::1] arr) → ndarray¶

encryptAComplex(self, double complex[:, ::1] arr, double scale=0, int scale_bits=0) → ndarray¶

encryptAFrac(self, double[:, ::1] arr, double scale=0, int scale_bits=0) → ndarray¶

encryptAInt(self, int64_t[:, ::1] arr) → ndarray¶

encryptAPtxt(self, PyPtxt[:] ptxt) → ndarray¶

encryptBGV(self, int64_t[:] arr, PyCtxt ctxt=None) → PyCtxt¶

Encrypts a 1D vector of int values into a PyCtxt ciphertext. If provided a ciphertext, encrypts the value inside it. :param value: value to encrypt. :type value: int :param ctxt: Optional destination ciphertext. :type ctxt: PyCtxt, optional

Returns:: the ciphertext containing the encrypted plaintext
Return type:: PyCtxt

encryptComplex(self, double complex[:] arr, PyCtxt ctxt=None, double scale=0, int scale_bits=0) → PyCtxt¶

Encrypts a 1D vector of complex values into a PyCtxt ciphertext.

Encrypts a fractional vector using the current secret key, based on the current context. Value must be a complex (double, double) that will get truncated. If provided a ciphertext, encrypts the plaintext inside it.

Parameters:

arr (complex[]) – values to encrypt.
ctxt (PyCtxt, optional) – Optional destination ciphertext.
scale (double) – scale factor to apply to the values.

Returns:

the ciphertext containing the encrypted plaintext

Return type:

encryptFrac(self, double[:] arr, PyCtxt ctxt=None, double scale=0, int scale_bits=0) → PyCtxt¶

Encrypts a 1D vector of float values into a PyCtxt ciphertext.

Encrypts a fractional vector using the current secret key, based on the current context. Value must a decimal (float, double) that will get truncated. If provided a ciphertext, encrypts the plaintext inside it.

Parameters:

arr (float[]) – values to encrypt.
ctxt (PyCtxt, optional) – Optional destination ciphertext.
scale (double) – scale factor to apply to the values.

Returns:

the ciphertext containing the encrypted plaintext

Return type:

encryptInt(self, int64_t[:] arr, PyCtxt ctxt=None) → PyCtxt¶

Encrypts a 1D vector of int values into a PyCtxt ciphertext.

If provided a ciphertext, encrypts the value inside it.

Parameters:

value (int) – value to encrypt.
ctxt (PyCtxt, optional) – Optional destination ciphertext.

Returns:

the ciphertext containing the encrypted plaintext

Return type:

encryptPtxt(self, PyPtxt ptxt, PyCtxt ctxt=None) → PyCtxt¶

Encrypts an encoded PyPtxt plaintext into a PyCtxt ciphertext.

Encrypts an encoded PyPtxt plaintext using the current secret key, based on the current context. Plaintext must be a PyPtxt. If provided a ciphertext, encrypts the plaintext inside it.

Parameters:

ptxt (PyPtxt) – plaintext to encrypt.
ctxt (PyCtxt, optional) – Optional destination ciphertext.

Returns:

the ciphertext containing the encrypted plaintext

Return type:

Raises:

TypeError – if the plaintext doesn’t have a valid type.

flip(self, PyCtxt ctxt, bool in_new_ctxt=False) → PyCtxt¶

Swaps the two rows of a PyCtxt ciphertext with BFV scheme.

Requires previously initialized rotation keys with rotateKeyGen().

Parameters:

ctxt (PyCtxt) – ciphertext whose values are rotated.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

from_bytes_context(self, bytes content) → size_t¶

Restores current context from a bytes object

Parameters:: content (bytes) – bytes object obtained from to_bytes_context
Returns:: number of bytes saved/loaded
Return type:: size_t

from_bytes_public_key(self, bytes content) → size_t¶

Restores current public key from a bytes object

Parameters:: content (bytes) – bytes object obtained from to_bytes_public_key
Returns:: number of bytes saved/loaded
Return type:: size_t

from_bytes_relin_key(self, bytes content) → size_t¶

Restores current relin key from a bytes object

Parameters:: content (bytes) – bytes object obtained from to_bytes_relin_key
Returns:: number of bytes saved/loaded
Return type:: size_t

from_bytes_rotate_key(self, bytes content) → size_t¶

Restores current rotation key from a bytes object

Parameters:: content (bytes) – bytes object obtained from to_bytes_rotateKey
Returns:: number of bytes saved/loaded
Return type:: size_t

from_bytes_secret_key(self, bytes content) → size_t¶

Restores current secret key from a bytes object

Parameters:: content (bytes) – bytes object obtained from to_bytes_secret_key
Returns:: number of bytes saved/loaded
Return type:: size_t

get_nSlots(self) → size_t¶

Maximum number of slots fitting in a ciphertext.

Equivalent to n for BFV/BGV, and n/2 for CKKS.

Returns:: Maximum number of slots.
Return type:: int

get_plain_modulus(self) → uint64_t¶

Plaintext modulus of the current context.

Returns:: Plaintext modulus.
Return type:: int

get_poly_modulus_degree(self) → size_t¶

Plaintext coefficient of the current context.

The more, the bigger the ciphertexts are, thus allowing for more operations with correct decryption. Also, number of values in a ciphertext in both schemes.

Returns:: Plaintext coefficient.
Return type:: int

get_qi(self) → vector[uint64_t]¶

Returns the qi values (coeff. modulus values) used in the current context.

Returns:: qi values.
Return type:: vector[uint64_t]

get_scheme(self) → scheme_t¶

Scheme of the current context.

Returns:: Scheme.
Return type:: scheme_t

is_context_empty(self) → bool¶

True if the current Pyfhel instance has no context.

Returns:: True if there is no context. False if there is.
Return type:: bool

is_public_key_empty(self) → bool¶

True if the current Pyfhel instance has no public Key.

Returns:: True if there is no public Key. False if there is.
Return type:: bool

is_relin_key_empty(self) → bool¶

True if the current Pyfhel instance has no relinearization key.

Returns:: True if there is no relinearization Key. False if there is.
Return type:: bool

is_rotate_key_empty(self) → bool¶

True if the current Pyfhel instance has no rotation key.

Returns:: True if there is no rotation Key. False if there is.
Return type:: bool

is_secret_key_empty(self) → bool¶

True if the current Pyfhel instance has no secret Key.

Returns:: True if there is no secret Key. False if there is.
Return type:: bool

keyGen(self) → void¶

Generates a pair of secret/Public Keys.

Based on the current context, initializes a public/secret key pair.

Parameters:: None –
Returns:: None

load_context(self, fileName) → size_t¶

Restores context from a file

Parameters:: fileName (str, pathlib.Path) – Name of the file.
Returns:: number of bytes saved/loaded
Return type:: size_t

load_public_key(self, fileName) → size_t¶

Restores current public key from a file

Parameters:: fileName (str, pathlib.Path) – Name of the file.
Returns:: number of bytes saved/loaded
Return type:: size_t

load_relin_key(self, fileName) → size_t¶

Restores current relinearization keys from a file

Parameters:: fileName (str, pathlib.Path) – Name of the file.
Returns:: number of bytes saved/loaded
Return type:: size_t

load_rotate_key(self, fileName) → size_t¶

Restores current rotation Keys from a file

Parameters:: fileName (str, pathlib.Path) – Name of the file.
Returns:: number of bytes saved/loaded
Return type:: size_t

load_secret_key(self, fileName) → size_t¶

Restores current secret key from a file

Parameters:: fileName (str, pathlib.Path) – Name of the file.
Returns:: number of bytes saved/loaded
Return type:: size_t

maxBitCount(self, long poly_modulus_degree, int sec_level) → long¶

Returns the maximum number of bits that can be used to encode a number.

Parameters:

poly_modulus_degree (long) – Polynomial modulus degree.
sec_level (int) – Security level.

Returns:

Maximum number of bits that can be used to encode a number.

Return type:

long

mod_switch_to_next(self, cipher_or_plain, in_new_obj=False)¶

Reduces the ciphertext/plaintext modulus with next prime in the qi chain.

Parameters:: cipher_or_plain (PyCtxt|PyPtxt) – Ciphertext to reduce.
Returns:: None

mod_switch_to_next_ctxt(self, PyCtxt ctxt, bool in_new_ctxt=False) → PyCtxt¶

Reduces the ciphertext modulus with next prime in the qi chain.

Parameters:

ctxt (PyCtxt) – Ciphertext to reduce.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

mod_switch_to_next_ptxt(self, PyPtxt ptxt, bool in_new_ptxt=True) → PyPtxt¶

Reduces the plaintext modulus with next prime in the qi chain.

Parameters:

ptxt (PyPtxt) – Plaintext to reduce.
in_new_ptxt (bool) – result in a newly created plaintext

Returns:

resulting plaintext, the input transformed or a new one

Return type:

multDepth(self, max_depth=64, delta=0.1, x_y_z=(1, 10, 0.1), verbose=False)¶

Empirically determines the multiplicative depth of a Pyfhel Object for a given context. For this, it encrypts the inputs x, y and z with Fractional scheme and performs the following chained multiplication until the result deviates more than delta in absolute value:

> x * y * z * y * z * y * z * y * z …

After each multiplication, the ciphertext is relinearized and checked. Ideally, y and z should be inverses to avoid wrapping over modulo p. Requires the Pyfhel Object to have initialized context and pub/sec/relin keys.

multiply(self, PyCtxt ctxt, PyCtxt ctxt_other, bool in_new_ctxt=False) → PyCtxt¶

Multiply first PyCtxt ciphertext by the second PyCtxt ciphertext.

Multiplies two ciphertexts. Encoding must be the same. Requires same context and encryption with same public key. The result is applied to the first ciphertext.

Parameters:

ctxt (PyCtxt) – ciphertext multiplied with ctxt_other.
ctxt_other (PyCtxt) – ciphertext left untouched.
in_new_ctxt (bool) – result in a newly created ciphertext.

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

multiply_plain(self, PyCtxt ctxt, PyPtxt ptxt, bool in_new_ctxt=False) → PyCtxt¶

Multiply a PyCtxt ciphertext and a PyPtxt plaintext.

Multiplies a ciphertext and a plaintext. Encoding must be the same. Requires same context and encryption with same public key. The result is applied to the first ciphertext.

Parameters:

ctxt (PyCtxt) – ciphertext whose values are multiplied with ptxt.
ptxt (PyPtxt) – plaintext left untouched.

Returns:

resulting ciphertext, either the input transformed or a new one

Return type:

negate(self, PyCtxt ctxt, bool in_new_ctxt=False) → PyCtxt¶

Negate PyCtxt ciphertext value/s.

Parameters:

ctxt (PyCtxt) – ciphertext whose values are negated.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

noise_level(self, PyCtxt ctxt) → int¶

Computes the invariant noise budget (bits) of a PyCtxt ciphertext.

The invariant noise budget measures the amount of room there is for thenoise to grow while ensuring correct decryptions. Decrypts a PyCtxt ciphertext using the current secret key, based on the current context.

Parameters:: ctxt (PyCtxt) – ciphertext to be measured.
Returns:: the noise budget level
Return type:: int

poly_add(self, PyPoly p, PyPoly p_other, bool in_new_poly=False) → PyPoly¶

Sum two PyPoly polynomials: p + p_other.

Encoding must be consistent (TODO). The result is applied to the first polynomial or to a newly created one.

Parameters:

p (PyPoly) – polynomial whose values are added with p_other.
p_other (PyPoly) – polynomial left untouched.
in_new_poly (bool) – result in a newly created polynomial

Returns:

resulting polynomial, the input transformed or a new one.

Return type:

poly_from_ciphertext(self, PyCtxt ctxt, size_t i) → PyPoly¶: Gets the i-th underlying polynomial of a ciphertext

poly_from_coeff_vector(self, vector[cy_complex] coeff_vector, PyCtxt ref) → PyPoly¶: Generates a polynomial with given coefficients

poly_from_plaintext(self, PyCtxt ref, PyPtxt ptxt) → PyPoly¶: Gets the underlying polynomial of a plaintext

poly_invert(self, PyPoly p, bool in_new_poly=False) → PyPoly¶

Invert PyPoly polynomial: inverse(p)

Encoding must be consistent (TODO). The result is applied to the polynomial or to a newly created one.

Parameters:

p (PyPoly) – polynomial whose values are inverted.
in_new_poly (bool) – result in a newly created polynomial

Returns:

resulting polynomial, the input transformed or a new one.

Return type:

poly_multiply(self, PyPoly p, PyPoly p_other, bool in_new_poly=False) → PyPoly¶

Multiply two PyPoly polynomials: p * p_other.

Encoding must be consistent (TODO). The result is applied to the first polynomial or to a newly created one.

Parameters:

p (PyPoly) – polynomial whose values are multiplied with p_other.
p_other (PyPoly) – polynomial left untouched.
in_new_poly (bool) – result in a newly created polynomial

Returns:

resulting polynomial, the input transformed or a new one.

Return type:

poly_subtract(self, PyPoly p, PyPoly p_other, bool in_new_poly=False) → PyPoly¶

Subtract two PyPoly polynomials: p - p_other.

Encoding must be consistent (TODO). The result is applied to the first polynomial or to a newly created one.

Parameters:

p (PyPoly) – polynomial whose values are subtracted with p_other.
p_other (PyPoly) – polynomial left untouched.
in_new_poly (bool) – result in a newly created polynomial

Returns:

resulting polynomial, the input transformed or a new one.

Return type:

poly_to_ciphertext(self, PyPoly p, PyCtxt ctxt, size_t i) → void¶

Set chosen i-th polynimial in ctxt to p.

Encoding must be consistent (TODO).

Parameters:

p (PyPoly) – polynomial to be inserted.
ctxt (PyCtxt) – base ciphertext.
i (int) – number of polynomial in ctxt to be set.

Returns:

None

poly_to_plaintext(self, PyPoly p, PyPtxt ptxt) → void¶

Set the polynimial in ptxt to p.

Encoding must be consistent (TODO).

Parameters:

p (PyPoly) – polynomial to be inserted.
ptxt (PyPtxt) – base plaintext.

Returns:

None

polys_from_ciphertext(self, PyCtxt ctxt) → list¶: Generates a list of polynomials of the given ciphertext

power(self, PyCtxt ctxt, uint64_t expon, bool in_new_ctxt=False) → PyCtxt¶

Exponentiates PyCtxt ciphertext value/s to expon power.

Performs an exponentiation over a cyphertext. Requires previously initialized relinearization keys with relinearizeKeyGen(), since it applies relinearization after each multiplication.

Parameters:

ctxt (PyCtxt) – ciphertext whose value/s are exponetiated.
expon (int) – exponent.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

relinKeyGen(self) → void¶

Generates a relinearization Key.

Generates a relinearization Key, used to reduce size of the ciphertexts when multiplying or exponentiating them. This is needed due to the fact that ciphertexts grow in size after encrypted mults/exponentiations.

Based on the current context, initializes one relinearization key.

Parameters:: None –
Returns:: None

relinearize(self, PyCtxt ctxt) → void¶

Relinearizes a ciphertext.

Relinearizes a ciphertext. This functions relinearizes ctxt, reducing its size down to 2.

Parameters:: ctxt (PyCtxt) – the ciphertext to relinearize in-place
Returns:: None

rescale_to_next(self, PyCtxt ctxt) → void¶

Rescales a ciphertext by dividing it by one scale factor.

Parameters:: ctxt (PyCtxt) – Ciphertext to rescale.
Returns:: None

rotate(self, PyCtxt ctxt, int k, bool in_new_ctxt=False) → PyCtxt¶

Rotates cyclically PyCtxt ciphertext values k positions.

Performs a cyclic rotation over a cyphertext encoded in BATCH mode. Requires previously initialized rotation keys with rotateKeyGen().

Parameters:

ctxt (PyCtxt) – ciphertext whose values are rotated.
k (int) – number of positions to rotate.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

rotateKeyGen(self, vector[int] rot_steps={}) → void¶

Generates a rotation Key.

Generates a rotation Key, used to rotate cyclically the values inside the encrypted vector.

Based on the current context, initializes one rotation key.

Parameters:: rot_steps (vector of ints) – Number of positions to rotate. If non-empty, only these steps can be used as k in Pyfhel.rotate(ctxt, k), but they will yield faster rotations for non-power-of-two steps. If empty, generates a binary decompositon of rotations over n {1,2,4…,n/2}, and uses them to compose any rotation step k.
Returns:: None

save_context(self, fileName, unicode compr_mode=u'zstd') → size_t¶

Saves current context in a file

Parameters:

fileName (str, pathlib.Path) – Name of the file.
compr_mode (str) – Compression. One of “none”, “zlib”, “zstd”

Returns:

number of bytes saved/loaded

Return type:

size_t

save_public_key(self, fileName, unicode compr_mode=u'zstd') → size_t¶

Saves current public key in a file

Parameters:

fileName (str, pathlib.Path) – Name of the file.
compr_mode (str) – Compression. One of “none”, “zlib”, “zstd”

Returns:

number of bytes saved/loaded

Return type:

size_t

save_relin_key(self, fileName, unicode compr_mode=u'zstd') → size_t¶

Saves current relinearization keys in a file

Parameters:

fileName (str, pathlib.Path) – Name of the file.
compr_mode (str) – Compression. One of “none”, “zlib”, “zstd”

Returns:

number of bytes saved/loaded

Return type:

size_t

save_rotate_key(self, fileName, unicode compr_mode=u'zstd') → size_t¶

Saves current rotation Keys from a file

Parameters:

fileName (str, pathlib.Path) – Name of the file.
compr_mode (str) – Compression. One of “none”, “zlib”, “zstd”

Returns:

number of bytes saved/loaded

Return type:

size_t

save_secret_key(self, fileName, unicode compr_mode=u'zstd') → size_t¶

Saves current secret key in a file

Parameters:

fileName (str, pathlib.Path) – Name of the file.
compr_mode (str) – Compression. One of “none”, “zlib”, “zstd”

Returns:

number of bytes saved/loaded

Return type:

size_t

scalar_prod(self, PyCtxt ctxt, PyCtxt ctxt_other, bool in_new_ctxt=False, bool with_relin=True, bool with_mod_switch=True, size_t n_elements=0) → PyCtxt¶

Performs a scalar product between two PyCtxt ciphertexts.

Performs a scalar product between two ciphertexts. Encoding must be the same. Requires same context and encryption with same public key.

Parameters:

ctxt (PyCtxt) – ciphertext multiplied with ctxt_other.
ctxt_other (PyCtxt) – ciphertext left untouched.
n_elements (size_t) – number of elements to be considered on each vector. If 0, the full encrypted vectors are considered (get_n_slots/ctxt.size).
with_relin (bool) – whether to perform relinearization after multiplication.
with_mod_switch (bool) – whether to perform modulus switching after multiplication.
in_new_ctxt (bool) – result in a newly created ciphertext.

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

scalar_prod_plain(self, PyCtxt ctxt, PyPtxt ptxt_other, bool in_new_ctxt=False, bool with_relin=True, bool with_mod_switch=True, size_t n_elements=0) → PyCtxt¶

Performs a scalar product between two PyCtxt ciphertexts.

Performs a scalar product between two ciphertexts. Encoding must be the same. Requires same context and encryption with same public key.

Parameters:

ctxt (PyCtxt) – ciphertext multiplied with ctxt_other.
ptxt_other (PyPtxt) – plaintext left untouched.
n_elements (size_t) – number of elements to be considered on each vector. If 0, the full encrypted vectors are considered (get_n_slots/ctxt.size).
with_relin (bool) – whether to perform relinearization after multiplication.
with_mod_switch (bool) – whether to perform modulus switching after multiplication.
in_new_ctxt (bool) – result in a newly created ciphertext.

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

sizeof_context(self, unicode compr_mode=u'none') → size_t¶

Returns an upper bound on the size of the current context in bytes

Returns:: size of the current context in bytes
Return type:: size_t

sizeof_public_key(self, unicode compr_mode=u'none') → size_t¶

Returns an upper bound on the size of the current public key in bytes

Returns:: size of the current public key in bytes
Return type:: size_t

sizeof_relin_key(self, unicode compr_mode=u'none') → size_t¶

Returns an upper bound on the size of the current relinearization key in bytes

Returns:: size of the current relinearization key in bytes
Return type:: size_t

sizeof_rotate_key(self, unicode compr_mode=u'none') → size_t¶

Returns an upper bound on the size of the current rotation key in bytes

Returns:: size of the current rotation key in bytes
Return type:: size_t

sizeof_secret_key(self, unicode compr_mode=u'none') → size_t¶

Returns an upper bound on the size of the current secret key in bytes

Returns:: size of the current secret key in bytes
Return type:: size_t

square(self, PyCtxt ctxt, bool in_new_ctxt=False) → PyCtxt¶

Square PyCtxt ciphertext value/s.

Parameters:

ctxt (PyCtxt) – ciphertext whose values are squared.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

sub(self, PyCtxt ctxt, PyCtxt ctxt_other, bool in_new_ctxt=False) → PyCtxt¶

Substracts one PyCtxt ciphertext from another.

Substracts one ciphertext from another. Encoding must be the same. Requires same context and encryption with same public key. The result is stored/applied to the first ciphertext.

Parameters:

ctxt (PyCtxt) – ciphertext substracted by ctxt_other.
ctxt_other (PyCtxt) – ciphertext being substracted from ctxt.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type:

sub_plain(self, PyCtxt ctxt, PyPtxt ptxt, bool in_new_ctxt=False) → PyCtxt¶

Substracts a PyCtxt ciphertext and a plaintext.

Performs ctxt = ctxt - ptxt. Encoding must be the same. Requires same context and encryption with same public key. The result is stored/applied to the ciphertext.

Parameters:

ctxt (PyCtxt) – ciphertext substracted by ptxt.
ptxt (*) – plaintext substracted from ctxt.
in_new_ctxt (bool) – result in a newly created ciphertext

Returns:

resulting ciphertext, the input transformed or a new one

Return type: