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use crate::{CrtCiphertext, ServerKey};
impl ServerKey {
/// Homomorphically computes the opposite of a ciphertext encrypting an integer message.
///
/// This function computes the opposite of a message without checking if it exceeds the
/// capacity of the ciphertext.
///
/// The result is returned as a new ciphertext.
/// # Example
///
///```rust
/// use concrete_integer::gen_keys;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys(&PARAM_MESSAGE_2_CARRY_2);
///
/// let clear = 14_u64;
/// let basis = vec![2, 3, 5];
///
/// let mut ctxt = cks.encrypt_crt(clear, basis.clone());
///
/// sks.unchecked_crt_neg_assign(&mut ctxt);
///
/// // Decrypt
/// let res = cks.decrypt_crt(&ctxt);
/// assert_eq!(16, res);
/// ```
pub fn unchecked_crt_neg(&self, ctxt: &CrtCiphertext) -> CrtCiphertext {
let mut result = ctxt.clone();
self.unchecked_crt_neg_assign(&mut result);
result
}
/// Homomorphically computes the opposite of a ciphertext encrypting an integer message.
///
/// This function computes the opposite of a message without checking if it exceeds the
/// capacity of the ciphertext.
///
/// The result is assigned to the `ct_left` ciphertext.
pub fn unchecked_crt_neg_assign(&self, ctxt: &mut CrtCiphertext) {
for ct_i in ctxt.blocks.iter_mut() {
self.key.unchecked_neg_assign(ct_i);
}
}
/// Homomorphically computes the opposite of a ciphertext encrypting an integer message.
///
/// # Example
///
///```rust
/// use concrete_integer::gen_keys;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys(&PARAM_MESSAGE_2_CARRY_2);
///
/// let clear = 14_u64;
/// let basis = vec![2, 3, 5];
///
/// let mut ctxt = cks.encrypt_crt(clear, basis.clone());
///
/// sks.smart_crt_neg_assign(&mut ctxt);
///
/// // Decrypt
/// let res = cks.decrypt_crt(&ctxt);
/// assert_eq!(16, res);
/// ```
pub fn smart_crt_neg_assign(&self, ctxt: &mut CrtCiphertext) {
if !self.is_crt_neg_possible(ctxt) {
self.full_extract(ctxt);
}
self.unchecked_crt_neg_assign(ctxt);
}
pub fn smart_crt_neg(&self, ctxt: &mut CrtCiphertext) -> CrtCiphertext {
if !self.is_crt_neg_possible(ctxt) {
self.full_extract(ctxt);
}
self.unchecked_crt_neg(ctxt)
}
pub fn is_crt_neg_possible(&self, ctxt: &CrtCiphertext) -> bool {
for ct_i in ctxt.blocks.iter() {
if !self.key.is_neg_possible(ct_i) {
return false;
}
}
true
}
}