encaps example

libcrux-ml-kem/examples/encapsulate.rs

@@ -0,0 +1,15 @@
+use libcrux_ml_kem::{kyber768, ENCAPS_SEED_SIZE, KEY_GENERATION_SEED_SIZE};
+use rand::{rngs::OsRng, RngCore};
+
+fn main() {
+    let mut randomness = [0u8; KEY_GENERATION_SEED_SIZE];
+    OsRng.fill_bytes(&mut randomness);
+
+    let key_pair = kyber768::generate_key_pair(randomness);
+
+    let mut randomness = [0u8; ENCAPS_SEED_SIZE];
+    for _ in 0..100_000 {
+        OsRng.fill_bytes(&mut randomness);
+        let _ = kyber768::encapsulate(key_pair.public_key(), randomness);
+    }
+}

libcrux-ml-kem/src/constants.rs

@@ -14,7 +14,7 @@ pub(crate) const BITS_PER_RING_ELEMENT: usize = COEFFICIENTS_IN_RING_ELEMENT * 1
 pub(crate) const BYTES_PER_RING_ELEMENT: usize = BITS_PER_RING_ELEMENT / 8;
 
 /// PKE message size
-pub(crate) const SHARED_SECRET_SIZE: usize = 32;
+pub const SHARED_SECRET_SIZE: usize = 32;
 
 pub(crate) const CPA_PKE_KEY_GENERATION_SEED_SIZE: usize = 32;
 

libcrux-ml-kem/src/lib.rs

@@ -48,8 +48,10 @@ use self::{
 };
 
 /// Seed size for key generation
-pub(crate) const KEY_GENERATION_SEED_SIZE: usize =
-    CPA_PKE_KEY_GENERATION_SEED_SIZE + SHARED_SECRET_SIZE;
+pub const KEY_GENERATION_SEED_SIZE: usize = CPA_PKE_KEY_GENERATION_SEED_SIZE + SHARED_SECRET_SIZE;
+
+/// Seed size for encapsulation
+pub const ENCAPS_SEED_SIZE: usize = constants::SHARED_SECRET_SIZE;
 
 /// Serialize the secret key.
 #[inline(always)]