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use crate::error::*;
use crate::{GaloisKey, RelinearizationKey};
pub mod base;
pub mod bfv;
pub mod ckks;
/// An interface for an evaluator.
pub trait Evaluator {
/// The plaintext type.
/// This is the type of the plaintext that the evaluator can operate on.
type Plaintext;
/// The ciphertext type.
/// This is the type of the ciphertext that the evaluator can operate on.
type Ciphertext;
/// Negates a ciphertext inplace.
/// * `a` - the value to negate
fn negate_inplace(
&self,
a: &mut Self::Ciphertext,
) -> Result<()>;
/// Negates a ciphertext into a new ciphertext.
/// * `a` - the value to negate
fn negate(
&self,
a: &Self::Ciphertext,
) -> Result<Self::Ciphertext>;
/// Add `a` and `b` and store the result in `a`.
/// * `a` - the accumulator
/// * `b` - the added value
fn add_inplace(
&self,
a: &mut Self::Ciphertext,
b: &Self::Ciphertext,
) -> Result<()>;
/// Adds `a` and `b`.
/// * `a` - first operand
/// * `b` - second operand
fn add(
&self,
a: &Self::Ciphertext,
b: &Self::Ciphertext,
) -> Result<Self::Ciphertext>;
/// Performs an addition reduction of multiple ciphertexts packed into a slice.
/// * `a` - a slice of ciphertexts to sum.
fn add_many(
&self,
a: &[Self::Ciphertext],
) -> Result<Self::Ciphertext>;
/// Performs an multiplication reduction of multiple ciphertexts packed into a slice. This
/// method creates a tree of multiplications with relinearization after each operation.
/// * `a` - a slice of ciphertexts to sum.
/// * `relin_keys` - the relinearization keys.
fn multiply_many(
&self,
a: &[Self::Ciphertext],
relin_keys: &RelinearizationKey,
) -> Result<Self::Ciphertext>;
/// Subtracts `b` from `a` and stores the result in `a`.
/// * `a` - the left operand and destination
/// * `b` - the right operand
fn sub_inplace(
&self,
a: &mut Self::Ciphertext,
b: &Self::Ciphertext,
) -> Result<()>;
/// Subtracts `b` from `a`.
/// * `a` - the left operand
/// * `b` - the right operand
fn sub(
&self,
a: &Self::Ciphertext,
b: &Self::Ciphertext,
) -> Result<Self::Ciphertext>;
/// Multiplies `a` and `b` and stores the result in `a`.
/// * `a` - the left operand and destination.
/// * `b` - the right operand.
fn multiply_inplace(
&self,
a: &mut Self::Ciphertext,
b: &Self::Ciphertext,
) -> Result<()>;
/// Multiplies `a` and `b`.
/// * `a` - the left operand.
/// * `b` - the right operand.
fn multiply(
&self,
a: &Self::Ciphertext,
b: &Self::Ciphertext,
) -> Result<Self::Ciphertext>;
/// Squares `a` and stores the result in `a`.
/// * `a` - the value to square.
fn square_inplace(
&self,
a: &mut Self::Ciphertext,
) -> Result<()>;
/// Squares `a`.
/// * `a` - the value to square.
fn square(
&self,
a: &Self::Ciphertext,
) -> Result<Self::Ciphertext>;
/// Given a ciphertext encrypted modulo q_1...q_k, this function switches the modulus down to q_1...q_{k-1} and
/// stores the result in the destination parameter.
///
/// # Remarks
/// In the BFV scheme if you've set up a coefficient modulus chain, this reduces the
/// number of bits needed to represent the ciphertext. This in turn speeds up operations.
///
/// If you haven't set up a modulus chain, don't use this.
///
/// TODO: what does this mean for CKKS?
fn mod_switch_to_next(
&self,
a: &Self::Ciphertext,
) -> Result<Self::Ciphertext>;
/// Given a ciphertext encrypted modulo q_1...q_k, this function switches the modulus down to q_1...q_{k-1} and
/// stores the result in the destination parameter. This does function does so in-place.
///
/// # Remarks
/// In the BFV scheme if you've set up a coefficient modulus chain, this reduces the
/// number of bits needed to represent the ciphertext. This in turn speeds up operations.
///
/// If you haven't set up a modulus chain, don't use this.
///
/// TODO: what does this mean for CKKS?
fn mod_switch_to_next_inplace(
&self,
a: &Self::Ciphertext,
) -> Result<()>;
/// Modulus switches an NTT transformed plaintext from modulo q_1...q_k down to modulo q_1...q_{k-1}.
fn mod_switch_to_next_plaintext(
&self,
a: &Self::Plaintext,
) -> Result<Self::Plaintext>;
/// Modulus switches an NTT transformed plaintext from modulo q_1...q_k down to modulo q_1...q_{k-1}.
/// This variant does so in-place.
fn mod_switch_to_next_inplace_plaintext(
&self,
a: &Self::Plaintext,
) -> Result<()>;
/// This functions raises encrypted to a power and stores the result in the destination parameter. Dynamic
/// memory allocations in the process are allocated from the memory pool pointed to by the given
/// MemoryPoolHandle. The exponentiation is done in a depth-optimal order, and relinearization is performed
/// automatically after every multiplication in the process. In relinearization the given relinearization keys
/// are used.
fn exponentiate(
&self,
a: &Self::Ciphertext,
exponent: u64,
relin_keys: &RelinearizationKey,
) -> Result<Self::Ciphertext>;
/// This functions raises encrypted to a power and stores the result in the destination parameter. Dynamic
/// memory allocations in the process are allocated from the memory pool pointed to by the given
/// MemoryPoolHandle. The exponentiation is done in a depth-optimal order, and relinearization is performed
/// automatically after every multiplication in the process. In relinearization the given relinearization keys
/// are used.
fn exponentiate_inplace(
&self,
a: &Self::Ciphertext,
exponent: u64,
relin_keys: &RelinearizationKey,
) -> Result<()>;
/// Adds a ciphertext and a plaintext.
/// * `a` - the ciphertext
/// * `b` - the plaintext
fn add_plain(
&self,
a: &Self::Ciphertext,
b: &Self::Plaintext,
) -> Result<Self::Ciphertext>;
/// Adds a ciphertext and a plaintext.
/// * `a` - the ciphertext
/// * `b` - the plaintext
fn add_plain_inplace(
&self,
a: &mut Self::Ciphertext,
b: &Self::Plaintext,
) -> Result<()>;
/// Subtract a plaintext from a ciphertext.
/// * `a` - the ciphertext
/// * `b` - the plaintext
fn sub_plain(
&self,
a: &Self::Ciphertext,
b: &Self::Plaintext,
) -> Result<Self::Ciphertext>;
/// Subtract a plaintext from a ciphertext and store the result in the ciphertext.
/// * `a` - the ciphertext
/// * `b` - the plaintext
fn sub_plain_inplace(
&self,
a: &mut Self::Ciphertext,
b: &Self::Plaintext,
) -> Result<()>;
/// Multiply a ciphertext by a plaintext.
/// * `a` - the ciphertext
/// * `b` - the plaintext
fn multiply_plain(
&self,
a: &Self::Ciphertext,
b: &Self::Plaintext,
) -> Result<Self::Ciphertext>;
/// Multiply a ciphertext by a plaintext and store in the ciphertext.
/// * `a` - the ciphertext
/// * `b` - the plaintext
fn multiply_plain_inplace(
&self,
a: &mut Self::Ciphertext,
b: &Self::Plaintext,
) -> Result<()>;
/// This functions relinearizes a ciphertext in-place, reducing it to 2 polynomials. This
/// reduces future noise growth under multiplication operations.
fn relinearize_inplace(
&self,
a: &mut Self::Ciphertext,
relin_keys: &RelinearizationKey,
) -> Result<()>;
/// This functions relinearizes a ciphertext, reducing it to 2 polynomials. This
/// reduces future noise growth under multiplication operations.
fn relinearize(
&self,
a: &Self::Ciphertext,
relin_keys: &RelinearizationKey,
) -> Result<Self::Ciphertext>;
/// Rotates plaintext matrix rows cyclically.
///
/// When batching is used with the BFV scheme, this function rotates the encrypted plaintext matrix rows
/// cyclically to the left (steps > 0) or to the right (steps < 0). Since the size of the batched matrix
/// is 2-by-(N/2), where N is the degree of the polynomial modulus, the number of steps to rotate must have
/// absolute value at most N/2-1.
///
/// * `a` - The ciphertext to rotate
/// * `steps` - The number of steps to rotate (positive left, negative right)
/// * `galois_keys` - The Galois keys
fn rotate_rows(
&self,
a: &Self::Ciphertext,
steps: i32,
galois_keys: &GaloisKey,
) -> Result<Self::Ciphertext>;
/// Rotates plaintext matrix rows cyclically. This variant does so in-place
///
/// When batching is used with the BFV scheme, this function rotates the encrypted plaintext matrix rows
/// cyclically to the left (steps > 0) or to the right (steps < 0). Since the size of the batched matrix
/// is 2-by-(N/2), where N is the degree of the polynomial modulus, the number of steps to rotate must have
/// absolute value at most N/2-1.
///
/// * `a` - The ciphertext to rotate
/// * `steps` - The number of steps to rotate (positive left, negative right)
/// * `galois_keys` - The Galois keys
fn rotate_rows_inplace(
&self,
a: &Self::Ciphertext,
steps: i32,
galois_keys: &GaloisKey,
) -> Result<()>;
/// Rotates plaintext matrix columns cyclically.
///
/// When batching is used with the BFV scheme, this function rotates the encrypted plaintext matrix columns
/// cyclically. Since the size of the batched matrix is 2-by-(N/2), where N is the degree of the polynomial
/// modulus, this means simply swapping the two rows. Dynamic memory allocations in the process are allocated
/// from the memory pool pointed to by the given MemoryPoolHandle.
///
/// * `encrypted` - The ciphertext to rotate
/// * `galoisKeys` - The Galois keys
fn rotate_columns(
&self,
a: &Self::Ciphertext,
galois_keys: &GaloisKey,
) -> Result<Self::Ciphertext>;
/// Rotates plaintext matrix columns cyclically. This variant does so in-place.
///
/// When batching is used with the BFV scheme, this function rotates the encrypted plaintext matrix columns
/// cyclically. Since the size of the batched matrix is 2-by-(N/2), where N is the degree of the polynomial
/// modulus, this means simply swapping the two rows. Dynamic memory allocations in the process are allocated
/// from the memory pool pointed to by the given MemoryPoolHandle.
///
/// * `encrypted` - The ciphertext to rotate
/// * `galoisKeys` - The Galois keys
fn rotate_columns_inplace(
&self,
a: &Self::Ciphertext,
galois_keys: &GaloisKey,
) -> Result<()>;
}