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use super::{RadixCiphertext, ServerKey, SignedRadixCiphertext};
use crate::core_crypto::commons::generators::DeterministicSeeder;
use crate::core_crypto::prelude::DefaultRandomGenerator;
use rayon::iter::{IndexedParallelIterator, IntoParallelIterator, ParallelIterator};
use std::num::NonZeroU64;
pub use tfhe_csprng::seeders::{Seed, Seeder};
impl ServerKey {
/// Generates an encrypted `num_block` blocks unsigned integer
/// taken uniformly in its full range using the given seed.
/// The encrypted value is oblivious to the server.
/// It can be useful to make server random generation deterministic.
///
/// ```rust
/// use tfhe::integer::gen_keys_radix;
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128;
/// use tfhe::Seed;
///
/// let size = 4;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys_radix(PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128, size);
///
/// let ct_res = sks.par_generate_oblivious_pseudo_random_unsigned_integer(Seed(0), size as u64);
///
/// // Decrypt:
/// let dec_result: u64 = cks.decrypt(&ct_res);
///
/// assert!(dec_result < 1 << (2 * size));
/// ```
pub fn par_generate_oblivious_pseudo_random_unsigned_integer(
&self,
seed: Seed,
num_blocks: u64,
) -> RadixCiphertext {
assert!(self.message_modulus().0.is_power_of_two());
let range_log_size = self.message_modulus().0.ilog2() as u64 * num_blocks;
let random_bits_count = range_log_size;
let sk = &self.key;
let message_bits_count = self.message_modulus().0.ilog2() as u64;
let mut deterministic_seeder = DeterministicSeeder::<DefaultRandomGenerator>::new(seed);
let seeds: Vec<Seed> = (0..num_blocks)
.map(|_| deterministic_seeder.seed())
.collect();
let blocks = seeds
.into_par_iter()
.enumerate()
.map(|(i, seed)| {
let i = i as u64;
if i * message_bits_count < random_bits_count {
// if we generate 5 bits of noise in n blocks of 2 bits, the third (i=2) block
// must have only one bit of random
if random_bits_count < (i + 1) * message_bits_count {
let top_message_bits_count = random_bits_count - i * message_bits_count;
assert!(top_message_bits_count <= message_bits_count);
sk.generate_oblivious_pseudo_random(seed, top_message_bits_count)
} else {
sk.generate_oblivious_pseudo_random(seed, message_bits_count)
}
} else {
self.key.create_trivial(0)
}
})
.collect::<Vec<_>>();
RadixCiphertext::from(blocks)
}
/// Generates an encrypted `num_block` blocks unsigned integer
/// taken uniformly in `[0, 2^random_bits_count[` using the given seed.
/// The encrypted value is oblivious to the server.
/// It can be useful to make server random generation deterministic.
///
/// ```rust
/// use tfhe::integer::gen_keys_radix;
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128;
/// use tfhe::Seed;
///
/// let size = 4;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys_radix(PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128, size);
///
/// let random_bits_count = 3;
///
/// let ct_res = sks.par_generate_oblivious_pseudo_random_unsigned_integer_bounded(
/// Seed(0),
/// random_bits_count,
/// size as u64,
/// );
///
/// // Decrypt:
/// let dec_result: u64 = cks.decrypt(&ct_res);
/// assert!(dec_result < (1 << random_bits_count));
/// ```
pub fn par_generate_oblivious_pseudo_random_unsigned_integer_bounded(
&self,
seed: Seed,
random_bits_count: u64,
num_blocks: u64,
) -> RadixCiphertext {
assert!(self.message_modulus().0.is_power_of_two());
let range_log_size = self.message_modulus().0.ilog2() as u64 * num_blocks;
assert!(
random_bits_count <= range_log_size,
"The range asked for a random value (=[0, 2^{random_bits_count}[) does not fit in the available range [0, 2^{range_log_size}[",
);
let message_bits_count = self.message_modulus().0.ilog2() as u64;
let mut deterministic_seeder = DeterministicSeeder::<DefaultRandomGenerator>::new(seed);
let seeds: Vec<Seed> = (0..num_blocks)
.map(|_| deterministic_seeder.seed())
.collect();
let blocks = seeds
.into_par_iter()
.enumerate()
.map(|(i, seed)| {
let i = i as u64;
if i * message_bits_count < random_bits_count {
// if we generate 5 bits of noise in n blocks of 2 bits, the third (i=2) block
// must have only one bit of random
if random_bits_count < (i + 1) * message_bits_count {
let top_message_bits_count = random_bits_count - i * message_bits_count;
assert!(top_message_bits_count <= message_bits_count);
self.key
.generate_oblivious_pseudo_random(seed, top_message_bits_count)
} else {
self.key
.generate_oblivious_pseudo_random(seed, message_bits_count)
}
} else {
self.key.create_trivial(0)
}
})
.collect::<Vec<_>>();
RadixCiphertext::from(blocks)
}
/// Generates an encrypted `num_blocks_output` blocks unsigned integer
/// taken almost uniformly in [0, excluded_upper_bound[ using the given seed.
/// The encrypted value is oblivious to the server.
/// It can be useful to make server random generation deterministic.
/// The higher num_input_random_bits, the closer to a uniform the distribution will be (at the
/// cost of computation time).
/// It is recommended to use a multiple of `log2_message_modulus`
/// as `num_input_random_bits`
///
/// ```rust
/// use std::num::NonZeroU64;
/// use tfhe::integer::gen_keys_radix;
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128;
/// use tfhe::Seed;
///
/// let size = 4;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys_radix(PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128, size);
///
/// let num_input_random_bits = 5;
/// let excluded_upper_bound = NonZeroU64::new(3).unwrap();
/// let num_blocks_output = 8;
///
/// let ct_res = sks.par_generate_oblivious_pseudo_random_unsigned_custom_range(
/// Seed(0),
/// num_input_random_bits,
/// excluded_upper_bound,
/// num_blocks_output,
/// );
///
/// // Decrypt:
/// let dec_result: u64 = cks.decrypt(&ct_res);
///
/// assert!(dec_result < excluded_upper_bound.get());
/// ```
pub fn par_generate_oblivious_pseudo_random_unsigned_custom_range(
&self,
seed: Seed,
num_input_random_bits: u64,
excluded_upper_bound: NonZeroU64,
num_blocks_output: u64,
) -> RadixCiphertext {
let excluded_upper_bound = excluded_upper_bound.get();
assert!(self.message_modulus().0.is_power_of_two());
let message_bits_count = self.message_modulus().0.ilog2() as u64;
assert!(
!excluded_upper_bound.is_power_of_two(),
"Use the cheaper par_generate_oblivious_pseudo_random_unsigned_integer_bounded function instead"
);
let num_bits_output = num_blocks_output * message_bits_count;
assert!((excluded_upper_bound as f64) < 2_f64.powi(num_bits_output as i32), "num_blocks_output(={num_blocks_output}) is too small to hold an integer up to excluded_upper_bound(=excluded_upper_bound)");
let post_mul_num_bits =
num_input_random_bits + (excluded_upper_bound as f64).log2().ceil() as u64;
let num_blocks = post_mul_num_bits.div_ceil(message_bits_count);
let random_input = self.par_generate_oblivious_pseudo_random_unsigned_integer_bounded(
seed,
num_input_random_bits,
num_blocks,
);
let random_multiplied = self.scalar_mul_parallelized(&random_input, excluded_upper_bound);
let mut result =
self.scalar_right_shift_parallelized(&random_multiplied, num_input_random_bits);
// Adjust the number of leading (MSB) trivial zeros blocks
result
.blocks
.resize(num_blocks_output as usize, self.key.create_trivial(0));
result
}
}
impl ServerKey {
/// Generates an encrypted `num_block` blocks signed integer
/// taken uniformly in its full range using the given seed.
/// The encrypted value is oblivious to the server.
/// It can be useful to make server random generation deterministic.
///
/// ```rust
/// use tfhe::integer::gen_keys_radix;
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128;
/// use tfhe::Seed;
///
/// let size = 4;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys_radix(PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128, size);
///
/// let ct_res = sks.par_generate_oblivious_pseudo_random_signed_integer(Seed(0), size as u64);
///
/// // Decrypt:
/// let dec_result: i64 = cks.decrypt_signed(&ct_res);
/// assert!(dec_result < 1 << (2 * size - 1));
/// assert!(dec_result >= -(1 << (2 * size - 1)));
/// ```
pub fn par_generate_oblivious_pseudo_random_signed_integer(
&self,
seed: Seed,
num_blocks: u64,
) -> SignedRadixCiphertext {
assert!(self.message_modulus().0.is_power_of_two());
let message_bits_count = self.message_modulus().0.ilog2() as u64;
let mut deterministic_seeder = DeterministicSeeder::<DefaultRandomGenerator>::new(seed);
let seeds: Vec<Seed> = (0..num_blocks)
.map(|_| deterministic_seeder.seed())
.collect();
let blocks = seeds
.into_par_iter()
.map(|seed| {
self.key
.generate_oblivious_pseudo_random(seed, message_bits_count)
})
.collect::<Vec<_>>();
SignedRadixCiphertext::from(blocks)
}
/// Generates an encrypted `num_block` blocks signed integer
/// taken uniformly in `[0, 2^random_bits_count[` using the given seed.
/// The encrypted value is oblivious to the server.
/// It can be useful to make server random generation deterministic.
///
/// ```rust
/// use tfhe::integer::gen_keys_radix;
/// use tfhe::shortint::parameters::PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128;
/// use tfhe::Seed;
///
/// let size = 4;
///
/// let random_bits_count = 3;
///
/// // Generate the client key and the server key:
/// let (cks, sks) = gen_keys_radix(PARAM_MESSAGE_2_CARRY_2_KS_PBS_GAUSSIAN_2M128, size);
///
/// let ct_res = sks.par_generate_oblivious_pseudo_random_signed_integer_bounded(
/// Seed(0),
/// random_bits_count,
/// size as u64,
/// );
///
/// // Decrypt:
/// let dec_result: i64 = cks.decrypt_signed(&ct_res);
/// assert!(dec_result >= 0);
/// assert!(dec_result < (1 << random_bits_count));
/// ```
pub fn par_generate_oblivious_pseudo_random_signed_integer_bounded(
&self,
seed: Seed,
random_bits_count: u64,
num_blocks: u64,
) -> SignedRadixCiphertext {
assert!(self.message_modulus().0.is_power_of_two());
let range_log_size = self.message_modulus().0.ilog2() as u64 * num_blocks;
#[allow(clippy::int_plus_one)]
{
assert!(
random_bits_count + 1 <= range_log_size,
"The range asked for a random value (=[0, 2^{}[) does not fit in the available range [-2^{}, 2^{}[",
random_bits_count, range_log_size-1, range_log_size-1,
);
}
let message_bits_count = self.message_modulus().0.ilog2() as u64;
let mut deterministic_seeder = DeterministicSeeder::<DefaultRandomGenerator>::new(seed);
let seeds: Vec<Seed> = (0..num_blocks)
.map(|_| deterministic_seeder.seed())
.collect();
let blocks = seeds
.into_par_iter()
.enumerate()
.map(|(i, seed)| {
let i = i as u64;
if i * message_bits_count < random_bits_count {
// if we generate 5 bits of noise in n blocks of 2 bits, the third (i=2)
// block must have only one bit of random
if random_bits_count < (i + 1) * message_bits_count {
let top_message_bits_count = random_bits_count - i * message_bits_count;
assert!(top_message_bits_count <= message_bits_count);
self.key
.generate_oblivious_pseudo_random(seed, top_message_bits_count)
} else {
self.key
.generate_oblivious_pseudo_random(seed, message_bits_count)
}
} else {
self.key.create_trivial(0)
}
})
.collect::<Vec<_>>();
SignedRadixCiphertext::from(blocks)
}
}