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use crate::ciphertext::RadixCiphertext;
use crate::server_key::CheckError;
use crate::server_key::CheckError::CarryFull;
use crate::ServerKey;
impl ServerKey {
/// Computes homomorphically an addition between two ciphertexts encrypting integer values.
///
/// This function computes the operation 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_radix;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let num_blocks = 4;
/// let (cks, sks) = gen_keys_radix(&PARAM_MESSAGE_2_CARRY_2, num_blocks);
///
/// let msg1 = 10;
/// let msg2 = 127;
///
/// let ct1 = cks.encrypt(msg1);
/// let ct2 = cks.encrypt(msg2);
///
/// // Compute homomorphically an addition:
/// let ct_res = sks.unchecked_add(&ct1, &ct2);
///
/// // Decrypt:
/// let dec_result = cks.decrypt(&ct_res);
/// assert_eq!(dec_result, msg1 + msg2);
/// ```
pub fn unchecked_add(
&self,
ct_left: &RadixCiphertext,
ct_right: &RadixCiphertext,
) -> RadixCiphertext {
let mut result = ct_left.clone();
self.unchecked_add_assign(&mut result, ct_right);
result
}
/// Computes homomorphically an addition between two ciphertexts encrypting integer values.
///
/// This function computes the operation without checking if it exceeds the capacity of the
/// ciphertext.
///
/// The result is assigned to the `ct_left` ciphertext.
/// ```rust
/// use concrete_integer::gen_keys_radix;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// let num_blocks = 4;
/// let (cks, sks) = gen_keys_radix(&PARAM_MESSAGE_2_CARRY_2, num_blocks);
///
/// let msg1 = 28;
/// let msg2 = 127;
///
/// let mut ct1 = cks.encrypt(msg1);
/// let ct2 = cks.encrypt(msg2);
///
/// // Compute homomorphically an addition:
/// sks.unchecked_add_assign(&mut ct1, &ct2);
///
/// // Decrypt:
/// let dec_ct1 = cks.decrypt(&ct1);
/// assert_eq!(dec_ct1, msg1 + msg2);
/// ```
pub fn unchecked_add_assign(&self, ct_left: &mut RadixCiphertext, ct_right: &RadixCiphertext) {
for (ct_left_i, ct_right_i) in ct_left.blocks.iter_mut().zip(ct_right.blocks.iter()) {
self.key.unchecked_add_assign(ct_left_i, ct_right_i);
}
}
/// Verifies if ct1 and ct2 can be added together.
///
/// # Example
///
///```rust
/// use concrete_integer::gen_keys_radix;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let num_blocks = 4;
/// let (cks, sks) = gen_keys_radix(&PARAM_MESSAGE_2_CARRY_2, num_blocks);
///
/// let msg1 = 46;
/// let msg2 = 87;
///
/// let ct1 = cks.encrypt(msg1);
/// let ct2 = cks.encrypt(msg2);
///
/// // Check if we can perform an addition
/// let res = sks.is_add_possible(&ct1, &ct2);
///
/// assert_eq!(true, res);
/// ```
pub fn is_add_possible(&self, ct_left: &RadixCiphertext, ct_right: &RadixCiphertext) -> bool {
for (ct_left_i, ct_right_i) in ct_left.blocks.iter().zip(ct_right.blocks.iter()) {
if !self.key.is_add_possible(ct_left_i, ct_right_i) {
return false;
}
}
true
}
/// Computes homomorphically an addition between two ciphertexts encrypting integer values.
///
/// If the operation can be performed, the result is returned in a new ciphertext.
/// Otherwise [CheckError::CarryFull] is returned.
///
/// # Example
///
/// ```rust
/// use concrete_integer::gen_keys_radix;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let num_blocks = 4;
/// let (cks, sks) = gen_keys_radix(&PARAM_MESSAGE_2_CARRY_2, num_blocks);
///
/// let msg1 = 41;
/// let msg2 = 101;
///
/// let ct1 = cks.encrypt(msg1);
/// let ct2 = cks.encrypt(msg2);
///
/// // Compute homomorphically an addition:
/// let ct_res = sks.checked_add(&ct1, &ct2);
///
/// match ct_res {
/// Err(x) => panic!("{:?}", x),
/// Ok(y) => {
/// let clear = cks.decrypt(&y);
/// assert_eq!(msg1 + msg2, clear);
/// }
/// }
/// ```
pub fn checked_add(
&self,
ct_left: &RadixCiphertext,
ct_right: &RadixCiphertext,
) -> Result<RadixCiphertext, CheckError> {
if self.is_add_possible(ct_left, ct_right) {
let mut result = ct_left.clone();
self.unchecked_add_assign(&mut result, ct_right);
Ok(result)
} else {
Err(CarryFull)
}
}
/// Computes homomorphically an addition between two ciphertexts encrypting integer values.
///
/// If the operation can be performed, the result is stored in the `ct_left` ciphertext.
/// Otherwise [CheckError::CarryFull] is returned, and `ct_left` is not modified.
///
/// # Example
///
/// ```rust
/// use concrete_integer::gen_keys_radix;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let num_blocks = 4;
/// let (cks, sks) = gen_keys_radix(&PARAM_MESSAGE_2_CARRY_2, num_blocks);
///
/// let msg1 = 41;
/// let msg2 = 101;
///
/// let mut ct1 = cks.encrypt(msg1);
/// let ct2 = cks.encrypt(msg2);
///
/// // Compute homomorphically an addition:
/// let res = sks.checked_add_assign(&mut ct1, &ct2);
///
/// assert!(res.is_ok());
///
/// let clear = cks.decrypt(&ct1);
/// assert_eq!(msg1 + msg2, clear);
/// ```
pub fn checked_add_assign(
&self,
ct_left: &mut RadixCiphertext,
ct_right: &RadixCiphertext,
) -> Result<(), CheckError> {
if self.is_add_possible(ct_left, ct_right) {
self.unchecked_add_assign(ct_left, ct_right);
Ok(())
} else {
Err(CarryFull)
}
}
/// Computes homomorphically an addition between two ciphertexts encrypting integer values.
///
/// # Example
///
/// ```rust
/// use concrete_integer::gen_keys_radix;
/// use concrete_shortint::parameters::PARAM_MESSAGE_2_CARRY_2;
///
/// // Generate the client key and the server key:
/// let num_blocks = 4;
/// let (cks, sks) = gen_keys_radix(&PARAM_MESSAGE_2_CARRY_2, num_blocks);
///
/// let msg1 = 14;
/// let msg2 = 97;
///
/// let mut ct1 = cks.encrypt(msg1);
/// let mut ct2 = cks.encrypt(msg2);
///
/// // Compute homomorphically an addition:
/// let ct_res = sks.smart_add(&mut ct1, &mut ct2);
///
/// // Decrypt:
/// let dec_result = cks.decrypt(&ct_res);
/// assert_eq!(dec_result, msg1 + msg2);
/// ```
pub fn smart_add(
&self,
ct_left: &mut RadixCiphertext,
ct_right: &mut RadixCiphertext,
) -> RadixCiphertext {
if !self.is_add_possible(ct_left, ct_right) {
self.full_propagate(ct_left);
self.full_propagate(ct_right);
}
self.unchecked_add(ct_left, ct_right)
}
pub fn smart_add_assign(&self, ct_left: &mut RadixCiphertext, ct_right: &mut RadixCiphertext) {
//If the ciphertext cannot be added together without exceeding the capacity of a ciphertext
if !self.is_add_possible(ct_left, ct_right) {
self.full_propagate(ct_left);
self.full_propagate(ct_right);
}
self.unchecked_add_assign(ct_left, ct_right);
}
}