templates.encryption_scheme module¶

Generic classes used for creating an encryption scheme.

class templates.encryption_scheme.Ciphertext(raw_value, scheme, **_kwargs)[source]¶

Bases: Generic[KM, PT, RP, CV]

Object that contains the ciphertext value for a particular EncryptionScheme. Also includes functionality for arithmetic operations on ciphertexts.

__add__(other)[source]¶

Add other to the underlying plaintext of this ciphertext.

Parameters:: other (Union[Self, TypeVar(PT)]) – Plaintext value or other ciphertext. If Plaintext value we add the plaintext value to the underlying ciphertext. If ciphertext we add the both underlying ciphertexts.
Return type:: Self
Returns:: Addition of other to this ciphertext.

__init__(raw_value, scheme, **_kwargs)[source]¶

Constructs a Ciphertext with the given ciphertext value encrypted using the specified scheme.

Parameters:

raw_value (TypeVar(CV)) – value of the ciphertext
scheme (EncryptionScheme[TypeVar(KM), TypeVar(PT), TypeVar(RP), TypeVar(CV), Self]) – encryption scheme used for creating this ciphertext
**_kwargs (Any) – Optional extra keyword arguments for the constructor.

__mul__(other)[source]¶

Multiply other with the underlying plaintext of this ciphertext.

Parameters:: other (Union[Self, TypeVar(PT)]) – Plaintext value or other ciphertext. If Plaintext value we multiply the plaintext value with the underlying ciphertext. If ciphertext we multiply the both underlying ciphertexts.
Return type:: Self
Returns:: Multiplication of other with this ciphertext.

__neg__()[source]¶

Negate the underlying plaintext of this ciphertext.

Return type:: Self
Returns:: Negated ciphertext.

__pow__(power)[source]¶

Exponentiate underlying plaintext of this ciphertext with the given exponent.

Parameters:: power (int) – Exponent to which the underlying plaintext should be exponentiated.
Return type:: Self
Returns:: Exponentiation of ciphertext to the given power.

__radd__(other)¶

Add other to the underlying plaintext of this ciphertext.

Parameters:: other (Union[Self, TypeVar(PT)]) – Plaintext value or other ciphertext. If Plaintext value we add the plaintext value to the underlying ciphertext. If ciphertext we add the both underlying ciphertexts.
Return type:: Self
Returns:: Addition of other to this ciphertext.

__rmul__(other)¶

Multiply other with the underlying plaintext of this ciphertext.

Parameters:: other (Union[Self, TypeVar(PT)]) – Plaintext value or other ciphertext. If Plaintext value we multiply the plaintext value with the underlying ciphertext. If ciphertext we multiply the both underlying ciphertexts.
Return type:: Self
Returns:: Multiplication of other with this ciphertext.

__rsub__(other)[source]¶

Subtract other from the underlying plaintext of this ciphertext.

Parameters:: other (Union[Self, TypeVar(PT)]) – Plaintext value or other ciphertext. If Plaintext value we subtract the plaintext value from the underlying ciphertext. If ciphertext we subtract the both underlying ciphertexts.
Return type:: Self
Returns:: Subtraction of other from this ciphertext.

__str__()[source]¶

Return type:: str
Returns:: String representation of Ciphertext.

__sub__(other)[source]¶

Subtract other from the underlying plaintext of this ciphertext.

Parameters:: other (Union[Self, TypeVar(PT)]) – Plaintext value or other ciphertext. If Plaintext value we subtract the plaintext value from the underlying ciphertext. If ciphertext we subtract the both underlying ciphertexts.
Raises:: TypeError – When the other object has an unsupported type for subtraction from this ciphertext.
Return type:: Self
Returns:: Subtraction of other from this ciphertext.

property value: CV¶

Raw value of the ciphertext.

Returns:: Value of the ciphertext

class templates.encryption_scheme.EncodedPlaintext(value, scheme)[source]¶

Bases: Generic[RP]

Class that contains the encoding of a plaintext for a particular scheme.

Constructs an EncodedPlaintext with the given value and encoding as specified in the scheme.

Parameters:

value (TypeVar(RP)) – value of the plaintext after encoding
scheme (EncryptionScheme[Any, Any, TypeVar(RP), Any, Any]) – encryption scheme that specifies the used encoding

Raises:

TypeError – provided scheme has the incorrect type.

__post_init__()[source]¶

Validate encryption scheme.

Raises:: TypeError – Scheme is of the wrong type.
Return type:: None

scheme: EncryptionScheme[Any, Any, TypeVar(RP), Any, Any]¶

value: TypeVar(RP)¶

class templates.encryption_scheme.EncryptionScheme(*_args, **_kwargs)[source]¶

Bases: InstanceManagerMixin, ABC, Generic[KM, PT, RP, CV, CT]

Abstract base class to define generic EncryptionScheme functionality. Can be used for all kinds of encryption scheme (e.g. Asymmetric, Symmetric).

Most easily constructed using the from_security_parameter method.

All abstract methods should be implemented by subclasses.

abstractmethod __eq__(other)[source]¶

Method that determines whether two EncryptionSchemes are the same

Parameters:: other (object) – EncryptionScheme to be compared to self
Return type:: bool
Returns:: whether they are the same scheme

__init__(*_args, **_kwargs)[source]¶

Construct a new EncryptionScheme.

Parameters:

*_args (Any) – Optional extra arguments for the constructor of a concrete implementation.
**_kwargs (Any) – Optional extra keyword arguments for the constructor of a concrete implementation.

add(ciphertext_1, ciphertext_2)[source]¶

Add the underlying plaintext value of ciphertext_1 with the (underlying) plaintext value of ciphertext_2. Where ciphertext_2 can either be another ciphertext or a plaintext, depending on the scheme.

Parameters:

ciphertext_1 (TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])) – First Ciphertext of which the underlying plaintext is added.
ciphertext_2 (Union[TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any]), TypeVar(PT)]) – Either a second Ciphertext of which the underlying plaintext is multiplied with the first, or a Plaintext that is added with the underlying plaintext of the first Ciphertext.

Raises:

NotImplementedError – Raised when addition is not supported by this scheme.

Return type:

TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])

Returns:

A Ciphertext containing the encryption of the addition of both values.

abstractmethod decode(encoded_plaintext)[source]¶

Decode an EncodedPlaintext using the specified encoding scheme.

Parameters:: encoded_plaintext (EncodedPlaintext[TypeVar(RP)]) – Plaintext to be decoded.
Return type:: TypeVar(PT)
Returns:: Decoded Plaintext value

decrypt(ciphertext, apply_encoding=True)[source]¶

Decrypts the input ciphertext.

Parameters:

ciphertext (TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])) – Ciphertext to be decrypted.
apply_encoding (bool) – Boolean indicating whether the decrypted ciphertext is decoded before it is returned.

Return type:

TypeVar(PT)

Returns:

Plaintext decrypted value.

decrypt_sequence(ciphertext_sequence, apply_encoding=True)[source]¶

Decrypts the list of input ciphertext.

Parameters:

ciphertext_sequence (Iterable[TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])]) – Sequence of Ciphertext to be decrypted.
apply_encoding (bool) – Boolean indicating whether the decrypted ciphertext is decoded before it is returned.

Return type:

Iterator[TypeVar(PT)]

Returns:

A list of Plaintext decrypted values.

abstractmethod encode(plaintext)[source]¶

Encode a supported Plaintext using the specified encoding scheme.

Parameters:: plaintext (TypeVar(PT)) – Plaintext to be encoded.
Return type:: EncodedPlaintext[TypeVar(RP)]
Returns:: EncodedPlaintext object containing the encoded value.

encrypt(plaintext, apply_encoding=True)[source]¶

Encrypts the entered (encoded) Plaintext. Also encodes the Plaintext when this is required.

Parameters:

plaintext (Union[TypeVar(PT), EncodedPlaintext[TypeVar(RP)]]) – Plaintext or EncodedPlaintext to be encrypted.
apply_encoding (bool) – Boolean indicating whether a non-encoded plaintext should be encoded. If False, the plaintext is encrypted in raw form.

Return type:

TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])

Returns:

Ciphertext object containing the encrypted value of the plaintext.

encrypt_sequence(plaintext_sequence, apply_encoding=True)[source]¶

Encrypts the entered sequence of (encoded) Plaintext. Also encodes a Plaintext when this is required.

Parameters:

plaintext_sequence (Union[Iterable[TypeVar(PT)], Iterable[EncodedPlaintext[TypeVar(RP)]]]) – Sequence of Plaintext or EncodedPlaintext to be encrypted.
apply_encoding (bool) – Boolean indicating whether a non-encoded plaintext should be encoded. If False, the plaintext is encrypted in raw form.

Return type:

Iterator[TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])]

Returns:

Ciphertext object containing the encrypted value of the plaintext.

abstractmethod classmethod from_security_parameter(*args, **kwargs)[source]¶

Generate a new EncryptionScheme from a security parameter.

Parameters:

*args (Any) – Security parameter(s) and optional extra arguments for the EncryptionScheme constructor.
**kwargs (Any) – Security parameter(s) and optional extra arguments for the EncryptionScheme constructor.

Return type:

Self

Returns:

A new EncryptionScheme.

abstractmethod static generate_key_material(*args, **kwargs)[source]¶

Method to generate key material (format depending on the type of scheme) for this scheme.

Parameters:

*args (Any) – Required arguments to generate said key material.
**kwargs (Any) – Required keyword arguments to generate said key material.

Return type:

TypeVar(KM)

mul(ciphertext_1, ciphertext_2)[source]¶

Multiply the underlying plaintext value of ciphertext_1 with the (underlying) plaintext value of ciphertext_2. Where ciphertext_2 can either be another ciphertext or a plaintext, depending on the scheme.

Parameters:

ciphertext_1 (TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])) – First Ciphertext of which the underlying plaintext is multiplied.
ciphertext_2 (Union[TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any]), TypeVar(PT)]) – Either a second Ciphertext of which the underlying plaintext is multiplied with the first, or a Plaintext that is multiplied with the underlying plaintext of the first Ciphertext.

Raises:

NotImplementedError – Raised when multiplication is not supported by this scheme.

Return type:

TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])

Returns:

A Ciphertext containing the encryption of the product of both values.

neg(ciphertext)[source]¶

Negate the underlying plaintext of this ciphertext. I.e. if the original plaintext of this ciphertext was 5 this method returns the ciphertext that has -5 as underlying plaintext.

Parameters:: ciphertext (TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])) – Ciphertext of which the underlying plaintext should be negated.
Raises:: NotImplementedError – Raised when negation is not supported by this scheme.
Return type:: TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])
Returns:: Ciphertext object corresponding to the negated plaintext.

pow(ciphertext, power)[source]¶

Raise the underlying plaintext value of ciph with the exponent power.

Parameters:

ciphertext (TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])) – Ciphertext containing the plaintext base.
power (int) – Exponent to which the base should be raised.

Raises:

NotImplementedError – Raised when exponentiation is not supported by this scheme.

Return type:

TypeVar(CT, bound= Ciphertext[Any, Any, Any, Any])

Returns:

Ciphertext containing the value of the underlying plaintext of ciph raised to the given power.

exception templates.encryption_scheme.EncryptionSchemeWarning[source]¶

Bases: UserWarning

Issued to suggest cryptographic best practises.

class templates.encryption_scheme.SupportsNeg(*args, **kwargs)[source]¶

Bases: Protocol[T_co]

An ABC with one abstract method __neg__.