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//! Module with the definition of the compressed PublicKey.
use crate::core_crypto::entities::*;
use crate::shortint::backward_compatibility::public_key::CompressedPublicKeyVersions;
use crate::shortint::ciphertext::Ciphertext;
use crate::shortint::engine::ShortintEngine;
use crate::shortint::parameters::{AtomicPatternKind, MessageModulus, ShortintParameterSet};
use crate::shortint::ClientKey;
use serde::{Deserialize, Serialize};
use std::fmt::Debug;
use tfhe_versionable::Versionize;
/// A structure containing a compressed public key.
#[derive(Clone, Debug, PartialEq, Serialize, Deserialize, Versionize)]
#[versionize(CompressedPublicKeyVersions)]
pub struct CompressedPublicKey {
pub(crate) lwe_public_key: SeededLwePublicKeyOwned<u64>,
pub parameters: ShortintParameterSet,
pub atomic_pattern: AtomicPatternKind,
}
impl CompressedPublicKey {
/// Generate a public key.
///
/// # Example
///
/// ```rust
/// use tfhe::shortint::client_key::ClientKey;
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS;
/// use tfhe::shortint::public_key::CompressedPublicKey;
///
/// // Generate the client key:
/// let cks = ClientKey::new(PARAM_MESSAGE_2_CARRY_2_KS_PBS);
///
/// let pk = CompressedPublicKey::new(&cks);
/// ```
pub fn new(client_key: &ClientKey) -> Self {
ShortintEngine::with_thread_local_mut(|engine| engine.new_compressed_public_key(client_key))
}
/// Deconstruct a [`CompressedPublicKey`] into its constituents.
pub fn into_raw_parts(
self,
) -> (
SeededLwePublicKeyOwned<u64>,
ShortintParameterSet,
AtomicPatternKind,
) {
let Self {
lwe_public_key,
parameters,
atomic_pattern,
} = self;
(lwe_public_key, parameters, atomic_pattern)
}
/// Construct a [`CompressedPublicKey`] from its constituents.
///
/// # Panics
///
/// Panics if the constituents are not compatible with each others.
pub fn from_raw_parts(
lwe_public_key: SeededLwePublicKeyOwned<u64>,
parameters: ShortintParameterSet,
atomic_pattern: AtomicPatternKind,
) -> Self {
let expected_atomic_pattern =
AtomicPatternKind::Standard(parameters.encryption_key_choice().into());
assert_eq!(
atomic_pattern, expected_atomic_pattern,
"Mismatch between expected atomic pattern ({expected_atomic_pattern:?}) and \
provided atomic pattern ({atomic_pattern:?})"
);
let ciphertext_lwe_dimension = parameters.encryption_lwe_dimension();
assert_eq!(
(*lwe_public_key).lwe_size().to_lwe_dimension(),
ciphertext_lwe_dimension,
"Mismatch between the SeededLwePublicKeyOwned LweDimension ({:?}) and \
the provided parameters LweDimension ({:?})",
(*lwe_public_key).lwe_size().to_lwe_dimension(),
ciphertext_lwe_dimension,
);
assert_eq!(
(*lwe_public_key).ciphertext_modulus(),
parameters.ciphertext_modulus(),
"Mismatch between the SeededLwePublicKeyOwned CiphertextModulus ({:?}) and \
the provided parameters CiphertextModulus ({:?})",
(*lwe_public_key).ciphertext_modulus(),
parameters.ciphertext_modulus(),
);
Self {
lwe_public_key,
parameters,
atomic_pattern,
}
}
/// Encrypts a small integer message using the client key.
///
/// The input message is reduced to the encrypted message space modulus
///
/// # Example
///
/// ```rust
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS;
/// use tfhe::shortint::{ClientKey, CompressedPublicKey};
///
/// // Generate the client key:
/// let cks = ClientKey::new(PARAM_MESSAGE_2_CARRY_2_KS_PBS);
///
/// let pk = CompressedPublicKey::new(&cks);
///
/// // Encryption of one message that is within the encrypted message modulus:
/// let msg = 3;
/// let ct = pk.encrypt(msg);
///
/// let dec = cks.decrypt(&ct);
/// assert_eq!(msg, dec);
///
/// // Encryption of one message that is outside the encrypted message modulus:
/// let msg = 5;
/// let ct = pk.encrypt(msg);
///
/// let dec = cks.decrypt(&ct);
/// let modulus = cks.parameters().message_modulus().0;
/// assert_eq!(msg % modulus, dec);
/// ```
pub fn encrypt(&self, message: u64) -> Ciphertext {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_with_compressed_public_key(self, message)
})
}
/// [`Self::encrypt`] variant that can encrypt many messages efficiently at the same time.
pub fn encrypt_many(&self, messages: impl Iterator<Item = u64>) -> Vec<Ciphertext> {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_many_ciphertexts_with_compressed_public_key(self, messages)
})
}
/// Encrypts a small integer message using the client key with a specific message modulus
///
/// # Example
///
/// ```rust
/// use tfhe::shortint::parameters::{MessageModulus, PARAM_MESSAGE_2_CARRY_2_KS_PBS};
/// use tfhe::shortint::{ClientKey, CompressedPublicKey};
///
/// // Generate the client key:
/// let cks = ClientKey::new(PARAM_MESSAGE_2_CARRY_2_KS_PBS);
///
/// let pk = CompressedPublicKey::new(&cks);
///
/// let msg = 3;
///
/// // Encryption of one message:
/// let ct = pk.encrypt_with_message_modulus(msg, MessageModulus(6));
///
/// // Decryption:
/// let dec = cks.decrypt(&ct);
/// assert_eq!(msg, dec);
/// ```
pub fn encrypt_with_message_modulus(
&self,
message: u64,
message_modulus: MessageModulus,
) -> Ciphertext {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_with_message_modulus_and_compressed_public_key(
self,
message,
message_modulus,
)
})
}
/// [`Self::encrypt_with_message_modulus`] variant that can encrypt a message under several
/// moduli efficiently at the same time.
pub fn encrypt_with_many_message_moduli(
&self,
message: u64,
message_moduli: impl Iterator<Item = MessageModulus>,
) -> Vec<Ciphertext> {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_with_many_message_moduli_and_compressed_public_key(
self,
message,
message_moduli,
)
})
}
/// Encrypts an integer without reducing the input message modulus the message space
///
/// # Example
///
/// ```rust
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS;
/// use tfhe::shortint::{ClientKey, CompressedPublicKey};
///
/// // Generate the client key:
/// let cks = ClientKey::new(PARAM_MESSAGE_2_CARRY_2_KS_PBS);
///
/// let pk = CompressedPublicKey::new(&cks);
///
/// let msg = 7;
/// let ct = pk.unchecked_encrypt(msg);
/// // | ct |
/// // | carry | message |
/// // |-------|---------|
/// // | 0 1 | 1 1 |
///
/// let dec = cks.decrypt_message_and_carry(&ct);
/// assert_eq!(msg, dec);
/// ```
pub fn unchecked_encrypt(&self, message: u64) -> Ciphertext {
ShortintEngine::with_thread_local_mut(|engine| {
engine.unchecked_encrypt_with_compressed_public_key(self, message)
})
}
/// Encrypts a small integer message using the client key without padding bit.
///
/// The input message is reduced to the encrypted message space modulus
///
/// # Example
///
/// ```rust
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS;
/// use tfhe::shortint::{ClientKey, CompressedPublicKey};
///
/// // Generate the client key:
/// let cks = ClientKey::new(PARAM_MESSAGE_2_CARRY_2_KS_PBS);
/// // DISCLAIMER: Note that this parameter is not guaranteed to be secure
/// let pk = CompressedPublicKey::new(&cks);
///
/// // Encryption of one message that is within the encrypted message modulus:
/// let msg = 6;
/// let ct = pk.encrypt_without_padding(msg);
///
/// let dec = cks.decrypt_message_and_carry_without_padding(&ct);
/// assert_eq!(msg, dec);
/// ```
pub fn encrypt_without_padding(&self, message: u64) -> Ciphertext {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_without_padding_with_compressed_public_key(self, message)
})
}
/// [`Self::encrypt_without_padding`] variant that can encrypt many messages efficiently at the
/// same time.
pub fn encrypt_many_without_padding(
&self,
messages: impl Iterator<Item = u64>,
) -> Vec<Ciphertext> {
ShortintEngine::with_thread_local_mut(|engine| {
engine
.encrypt_many_ciphertexts_without_padding_with_compressed_public_key(self, messages)
})
}
/// Encrypts a small integer message using the client key without padding bit with some modulus.
/// The input message is reduced to the encrypted message space modulus
///
/// # Example
///
/// ```rust
/// use tfhe::shortint::parameters::{MessageModulus, PARAM_MESSAGE_2_CARRY_2_KS_PBS};
/// use tfhe::shortint::{ClientKey, CompressedPublicKey};
///
/// // Generate the client key:
/// let cks = ClientKey::new(PARAM_MESSAGE_2_CARRY_2_KS_PBS);
///
/// let pk = CompressedPublicKey::new(&cks);
///
/// let msg = 2;
/// let modulus = MessageModulus(3);
///
/// // Encryption of one message:
/// let ct = pk.encrypt_native_crt(msg, modulus);
///
/// // Decryption:
/// let dec = cks.decrypt_message_native_crt(&ct, modulus);
/// assert_eq!(msg, dec % modulus.0);
/// ```
pub fn encrypt_native_crt(&self, message: u64, message_modulus: MessageModulus) -> Ciphertext {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_native_crt_with_compressed_public_key(self, message, message_modulus)
})
}
/// [`Self::encrypt_native_crt`] variant that can encrypt a message under several moduli
/// efficiently at the same time.
pub fn encrypt_native_crt_with_many_message_moduli(
&self,
message: u64,
message_modulus: impl Iterator<Item = MessageModulus>,
) -> Vec<Ciphertext> {
ShortintEngine::with_thread_local_mut(|engine| {
engine.encrypt_native_crt_with_many_message_moduli_and_compressed_public_key(
self,
message,
message_modulus,
)
})
}
}