wip on RLWE

Cargo.lock

@@ -638,6 +638,7 @@ version = "0.1.0"
 dependencies = [
  "base2k",
  "rand_distr",
+ "sampling",
 ]
 
 [[package]]

rlwe/Cargo.toml

@@ -7,4 +7,5 @@ edition = "2024"
 
 [dependencies]
 base2k = {path="../base2k"}
+sampling = {path="../sampling"}
 rand_distr = {workspace = true}

rlwe/src/ciphertext.rs

@@ -1,16 +1,50 @@
 use crate::elem::Elem;
-use crate::parameters::Parameters;
 use crate::plaintext::Plaintext;
+use base2k::VecZnx;
 
 pub struct Ciphertext(pub Elem);
 
+/*
 impl Parameters {
-    pub fn new_ciphertext(&self, degree: usize, log_q: usize) -> Ciphertext {
-        Ciphertext(self.new_elem(degree, log_q))
+    pub fn new_ciphertext(&self, degree: usize, log_base2k: usize, log_q: usize) -> Ciphertext {
+        Ciphertext(self.new_elem(degree, log_base2k, log_q))
     }
 }
+ */
 
 impl Ciphertext {
+    pub fn new(n: usize, log_base2k: usize, log_q: usize, degree: usize) -> Self {
+        Self(Elem::new(n, log_base2k, log_q, degree))
+    }
+
+    pub fn n(&self) -> usize {
+        self.0.n()
+    }
+
+    pub fn degree(&self) -> usize {
+        self.0.degree()
+    }
+
+    pub fn log_q(&self) -> usize {
+        self.0.log_q()
+    }
+
+    pub fn limbs(&self) -> usize {
+        self.0.limbs()
+    }
+
+    pub fn at(&self, i: usize) -> &VecZnx {
+        self.0.at(i)
+    }
+
+    pub fn at_mut(&mut self, i: usize) -> &mut VecZnx {
+        self.0.at_mut(i)
+    }
+
+    pub fn log_base2k(&self) -> usize {
+        self.0.log_base2k()
+    }
+
     pub fn as_plaintext(&self) -> Plaintext {
         unsafe { Plaintext(std::ptr::read(&self.0)) }
     }

rlwe/src/elem.rs

@@ -1,18 +1,51 @@
 use crate::parameters::Parameters;
-use base2k::VecZnx;
+use base2k::{Infos, VecZnx};
 
 pub struct Elem {
     pub value: Vec<VecZnx>,
-    pub log_scale: usize,
+    pub log_base2k: usize,
+    pub log_q: usize,
 }
 
-impl Parameters {
-    pub fn new_elem(&self, degree: usize, log_q: usize) -> Elem {
+impl Elem {
+    pub fn new(n: usize, log_base2k: usize, log_q: usize, degree: usize) -> Self {
+        let limbs: usize = (log_q + log_base2k - 1) / log_base2k;
         let mut value: Vec<VecZnx> = Vec::new();
-        (0..degree + 1).for_each(|_| value.push(VecZnx::new(self.n(), log_q)));
-        Elem {
-            value: value,
-            log_scale: self.log_scale(),
+        (0..degree + 1).for_each(|_| value.push(VecZnx::new(n, limbs)));
+        Self {
+            value,
+            log_base2k,
+            log_q,
         }
     }
+
+    pub fn n(&self) -> usize {
+        self.value[0].n()
+    }
+
+    pub fn degree(&self) -> usize {
+        self.value.len()
+    }
+
+    pub fn limbs(&self) -> usize {
+        self.value[0].limbs()
+    }
+
+    pub fn log_base2k(&self) -> usize {
+        self.log_base2k
+    }
+
+    pub fn log_q(&self) -> usize {
+        self.log_q
+    }
+
+    pub fn at(&self, i: usize) -> &VecZnx {
+        assert!(i <= self.degree());
+        &self.value[i]
+    }
+
+    pub fn at_mut(&mut self, i: usize) -> &mut VecZnx {
+        assert!(i <= self.degree());
+        &mut self.value[i]
+    }
 }

rlwe/src/encryptor.rs

@@ -1 +1,114 @@
+use crate::ciphertext::Ciphertext;
+use crate::elem::Elem;
+use crate::keys::SecretKey;
+use crate::parameters::Parameters;
+use crate::plaintext::Plaintext;
+use base2k::sampling::Sampling;
+use base2k::{Module, SvpPPol, SvpPPolOps, VecZnx, VecZnxBig, VecZnxDft};
+use sampling::source::Source;
 
+pub struct EncryptorSk {
+    pub sk: SvpPPol,
+}
+
+impl EncryptorSk {
+    pub fn new(params: &Parameters, sk: &SecretKey) -> Self {
+        let mut sk_svp_ppol: SvpPPol = params.module().svp_new_ppol();
+        params.module().svp_prepare(&mut sk_svp_ppol, &sk.0);
+        Self { sk: sk_svp_ppol }
+    }
+
+    pub fn encrypt_rlwe_sk(
+        &self,
+        params: &Parameters,
+        ct: &mut Ciphertext,
+        pt: Option<&Plaintext>,
+        xa_source: &mut Source,
+        xe_source: &mut Source,
+        tmp_bytes: &mut [u8],
+    ) {
+        params.encrypt_rlwe_sk(ct, pt, &self.sk, xa_source, xe_source, tmp_bytes);
+    }
+}
+
+impl Parameters {
+    pub fn encrypt_rlwe_sk_tmp_bytes(&self, limbs: usize) -> usize {
+        encrypt_rlwe_sk_tmp_bytes(self.module(), limbs)
+    }
+
+    pub fn encrypt_rlwe_sk(
+        &self,
+        ct: &mut Ciphertext,
+        pt: Option<&Plaintext>,
+        sk: &SvpPPol,
+        xa_source: &mut Source,
+        xe_source: &mut Source,
+        tmp_bytes: &mut [u8],
+    ) {
+        encrypt_rlwe_sk(
+            self.module(),
+            &mut ct.0,
+            pt.map(|pt| &pt.0),
+            sk,
+            xa_source,
+            xe_source,
+            self.xe(),
+            tmp_bytes,
+        )
+    }
+}
+
+pub fn encrypt_rlwe_sk_tmp_bytes(module: &Module, limbs: usize) -> usize {
+    module.bytes_of_vec_znx_dft(limbs) + module.vec_znx_big_normalize_tmp_bytes()
+}
+
+pub fn encrypt_rlwe_sk(
+    module: &Module,
+    ct: &mut Elem,
+    pt: Option<&Elem>,
+    sk: &SvpPPol,
+    xa_source: &mut Source,
+    xe_source: &mut Source,
+    sigma: f64,
+    tmp_bytes: &mut [u8],
+) {
+    let limbs: usize = ct.limbs();
+
+    assert!(
+        tmp_bytes.len() >= encrypt_rlwe_sk_tmp_bytes(module, limbs),
+        "invalid tmp_bytes: tmp_bytes={} < encrypt_rlwe_sk_tmp_bytes={}",
+        tmp_bytes.len(),
+        encrypt_rlwe_sk_tmp_bytes(module, limbs)
+    );
+
+    let log_q: usize = ct.log_q();
+    let log_base2k: usize = ct.log_base2k();
+    let c1: &mut VecZnx = ct.at_mut(1);
+
+    // c1 <- Z_{2^prec}[X]/(X^{N}+1)
+    c1.fill_uniform(limbs, log_base2k, xa_source);
+
+    let bytes_of_vec_znx_dft = module.bytes_of_vec_znx_dft(limbs);
+
+    // Scratch space for DFT values
+    let mut buf_dft: VecZnxDft =
+        VecZnxDft::from_bytes(limbs, &mut tmp_bytes[..bytes_of_vec_znx_dft]);
+
+    // Applies buf_dft <- s * c1
+    module.svp_apply_dft(&mut buf_dft, sk, c1);
+
+    // Alias scratch space
+    let mut buf_big: VecZnxBig = buf_dft.as_vec_znx_big();
+
+    if let Some(pt) = pt {
+        // buf_big <- m - buf_big
+        module.vec_znx_big_sub_small_a_inplace(&mut buf_big, pt.at(0));
+    };
+
+    let carry: &mut [u8] = &mut tmp_bytes[bytes_of_vec_znx_dft..];
+
+    // c0 <- normalize(buf_big) + e
+    let c0: &mut VecZnx = ct.at_mut(0);
+    module.vec_znx_big_normalize(log_base2k, c0, &buf_big, carry);
+    c0.add_normal(log_base2k, log_q, xe_source, sigma, (sigma * 6.0).ceil());
+}

rlwe/src/key_generator.rs

@@ -0,0 +1 @@
+pub struct KeyGenerator {}

rlwe/src/keys.rs

@@ -0,0 +1,44 @@
+use crate::elem::Elem;
+use crate::encryptor::{encrypt_rlwe_sk, encrypt_rlwe_sk_tmp_bytes};
+use crate::parameters::Parameters;
+use base2k::{Module, Sampling, Scalar, SvpPPol, SvpPPolOps, VecZnx};
+use sampling::source::Source;
+
+pub struct SecretKey(pub Scalar);
+
+impl SecretKey {
+    pub fn new_ternary_prob(module: &Module, limbs: usize, prob: f64, source: &mut Source) -> Self {
+        let mut sk: Scalar = Scalar::new(module.n());
+        sk.fill_ternary_prob(prob, source);
+        SecretKey(sk)
+    }
+}
+
+pub struct PublicKey(pub Elem);
+
+impl PublicKey {
+    pub fn new(
+        params: &Parameters,
+        sk: &SvpPPol,
+        xa_source: &mut Source,
+        xe_source: &mut Source,
+        tmp_bytes: &mut [u8],
+    ) -> Self {
+        let mut pk: Elem = Elem::new(params.n(), params.log_base2k(), params.log_qp(), 1);
+        encrypt_rlwe_sk(
+            params.module(),
+            &mut pk,
+            None,
+            sk,
+            xa_source,
+            xe_source,
+            params.xe(),
+            tmp_bytes,
+        );
+        PublicKey(pk)
+    }
+
+    pub fn new_tmp_bytes(params: &Parameters) -> usize {
+        encrypt_rlwe_sk_tmp_bytes(params.module(), params.limbs_qp())
+    }
+}

rlwe/src/lib.rs

@@ -1,5 +1,7 @@
 pub mod ciphertext;
 pub mod elem;
 pub mod encryptor;
+pub mod key_generator;
+pub mod keys;
 pub mod parameters;
 pub mod plaintext;

rlwe/src/parameters.rs

@@ -55,7 +55,31 @@ impl Parameters {
         self.log_p
     }
 
+    pub fn log_qp(&self) -> usize {
+        self.log_q + self.log_p
+    }
+
+    pub fn limbs_q(&self) -> usize {
+        (self.log_q + self.log_base2k - 1) / self.log_base2k
+    }
+
+    pub fn limbs_qp(&self) -> usize {
+        (self.log_q + self.log_p + self.log_base2k - 1) / self.log_base2k
+    }
+
     pub fn log_base2k(&self) -> usize {
         self.log_base2k
     }
+
+    pub fn module(&self) -> &Module {
+        &self.module
+    }
+
+    pub fn xe(&self) -> f64 {
+        self.xe
+    }
+
+    pub fn xs(&self) -> usize {
+        self.xs
+    }
 }

rlwe/src/plaintext.rs

@@ -1,16 +1,50 @@
 use crate::ciphertext::Ciphertext;
 use crate::elem::Elem;
-use crate::parameters::Parameters;
+use base2k::VecZnx;
 
 pub struct Plaintext(pub Elem);
 
+/*
 impl Parameters {
     pub fn new_plaintext(&self, log_q: usize) -> Plaintext {
         Plaintext(self.new_elem(0, log_q))
     }
 }
+*/
 
 impl Plaintext {
+    pub fn new(n: usize, log_base2k: usize, log_q: usize) -> Self {
+        Self(Elem::new(n, log_base2k, log_q, 0))
+    }
+
+    pub fn n(&self) -> usize {
+        self.0.n()
+    }
+
+    pub fn degree(&self) -> usize {
+        self.0.degree()
+    }
+
+    pub fn log_q(&self) -> usize {
+        self.0.log_q()
+    }
+
+    pub fn limbs(&self) -> usize {
+        self.0.limbs()
+    }
+
+    pub fn at(&self, i: usize) -> &VecZnx {
+        self.0.at(i)
+    }
+
+    pub fn at_mut(&mut self, i: usize) -> &mut VecZnx {
+        self.0.at_mut(i)
+    }
+
+    pub fn log_base2k(&self) -> usize {
+        self.0.log_base2k()
+    }
+
     pub fn as_ciphertext(&self) -> Ciphertext {
         unsafe { Ciphertext(std::ptr::read(&self.0)) }
     }

sampling/src/source.rs

@@ -1,6 +1,6 @@
 use rand_chacha::rand_core::SeedableRng;
 use rand_chacha::ChaCha8Rng;
-use rand_core::RngCore;
+use rand_core::{OsRng, RngCore};
 
 const MAXF64: f64 = 9007199254740992.0;
 
@@ -8,6 +8,12 @@ pub struct Source {
     source: ChaCha8Rng,
 }
 
+pub fn new_seed() -> [u8; 32] {
+    let mut seed = [0u8; 32];
+    OsRng.fill_bytes(&mut seed);
+    seed
+}
+
 impl Source {
     pub fn new(seed: [u8; 32]) -> Source {
         Source {
@@ -21,6 +27,10 @@ impl Source {
         seed
     }
 
+    pub fn branch(&mut self) -> Self {
+        Source::new(self.new_seed())
+    }
+
     #[inline(always)]
     pub fn next_u64n(&mut self, max: u64, mask: u64) -> u64 {
         let mut x: u64 = self.next_u64() & mask;