Relax DKG ceremony constraints

ferveo-python/test/test_ferveo.py

@@ -135,6 +135,79 @@ def test_precomputed_tdec_doesnt_have_enough_messages():
         FerveoVariant.Precomputed, shares_num=4, threshold=4, shares_to_use=3
     )
 
+def test_dkg_has_min_shares():
+    total_shares_num = 5
+    min_shares_num = 3
+    threshold = 3
+
+    tau = 1
+    validator_keypairs = [Keypair.random() for _ in range(0, total_shares_num)]
+    validators = [
+        Validator(gen_eth_addr(i), keypair.public_key())
+        for i, keypair in enumerate(validator_keypairs)
+    ]
+    validators.sort(key=lambda v: v.address)
+
+    messages = []
+    for sender in validators:
+        dkg = Dkg(
+            tau=tau,
+            shares_num=min_shares_num,
+            security_threshold=threshold,
+            validators=validators,
+            me=sender,
+        )
+        messages.append(ValidatorMessage(sender, dkg.generate_transcript()))
+
+    dkg = Dkg(
+        tau=tau,
+        shares_num=min_shares_num,
+        security_threshold=threshold,
+        validators=validators,
+        me=validators[0],
+    )
+    pvss_aggregated = dkg.aggregate_transcripts(messages)
+    assert pvss_aggregated.verify(min_shares_num, messages)
+
+    dkg_pk_bytes = bytes(dkg.public_key)
+    dkg_pk = DkgPublicKey.from_bytes(dkg_pk_bytes)
+
+    msg = "abc".encode()
+    aad = "my-aad".encode()
+    ciphertext = encrypt(msg, aad, dkg_pk)
+
+    decryption_shares = []
+    for validator, validator_keypair in zip(validators, validator_keypairs):
+        dkg = Dkg(
+            tau=tau,
+            shares_num=total_shares_num,
+            security_threshold=threshold,
+            validators=validators,
+            me=validator,
+        )
+        pvss_aggregated = dkg.aggregate_transcripts(messages)
+        assert pvss_aggregated.verify(total_shares_num, messages)
+
+        decryption_share = decryption_share_for_variant(variant, pvss_aggregated)(
+            dkg, ciphertext.header, aad, validator_keypair
+        )
+        decryption_shares.append(decryption_share)
+
+    shared_secret = combine_shares_for_variant(variant, decryption_shares)
+
+    if variant == FerveoVariant.Simple and len(decryption_shares) < threshold:
+        with pytest.raises(ThresholdEncryptionError):
+            decrypt_with_shared_secret(ciphertext, aad, shared_secret)
+        return
+
+    if variant == FerveoVariant.Precomputed and len(decryption_shares) < total_shares_num:
+        with pytest.raises(ThresholdEncryptionError):
+            decrypt_with_shared_secret(ciphertext, aad, shared_secret)
+        return
+
+    plaintext = decrypt_with_shared_secret(ciphertext, aad, shared_secret)
+    assert bytes(plaintext) == msg
+
 
 PARAMS = [
     (1, FerveoVariant.Simple),

ferveo-wasm/tests/node.rs

@@ -8,8 +8,8 @@ use wasm_bindgen_test::*;
 
 type TestSetup = (
     u32,
-    usize,
-    usize,
+    u32,
+    u32,
     Vec<Keypair>,
     Vec<Validator>,
     ValidatorArray,
@@ -21,11 +21,12 @@ type TestSetup = (
 
 fn setup_dkg() -> TestSetup {
     let tau = 1;
-    let shares_num = 16;
+    let shares_num: u32 = 16;
     let security_threshold = shares_num * 2 / 3;
 
-    let validator_keypairs =
-        (0..shares_num).map(gen_keypair).collect::<Vec<Keypair>>();
+    let validator_keypairs = (0..shares_num as usize)
+        .map(gen_keypair)
+        .collect::<Vec<Keypair>>();
     let validators = validator_keypairs
         .iter()
         .enumerate()
@@ -38,8 +39,8 @@ fn setup_dkg() -> TestSetup {
     let messages = validators.iter().map(|sender| {
         let dkg = Dkg::new(
             tau,
-            shares_num as u32,
-            security_threshold as u32,
+            shares_num,
+            security_threshold,
             &validators_js,
             sender,
         )
@@ -54,8 +55,8 @@ fn setup_dkg() -> TestSetup {
 
     let mut dkg = Dkg::new(
         tau,
-        shares_num as u32,
-        security_threshold as u32,
+        shares_num,
+        security_threshold,
         &validators_js,
         &validators[0],
     )
@@ -112,8 +113,8 @@ fn tdec_simple() {
         .map(|(validator, keypair)| {
             let mut dkg = Dkg::new(
                 tau,
-                shares_num as u32,
-                security_threshold as u32,
+                shares_num,
+                security_threshold,
                 &validators_js,
                 &validator,
             )
@@ -166,8 +167,8 @@ fn tdec_precomputed() {
         .map(|(validator, keypair)| {
             let mut dkg = Dkg::new(
                 tau,
-                shares_num as u32,
-                security_threshold as u32,
+                shares_num,
+                security_threshold,
                 &validators_js,
                 &validator,
             )

ferveo/Cargo.toml

@@ -51,6 +51,7 @@ wasm-bindgen-derive = { version = "0.2.1", optional = true }
 criterion = "0.3" # supports pprof, # TODO: Figure out if/how we can update to 0.4
 digest = { version = "0.10.0", features = ["alloc"] }
 pprof = { version = "0.6", features = ["flamegraph", "criterion"] }
+test-case = "3.3.1"
 
 # WASM bindings
 console_error_panic_hook = "0.1.7"

ferveo/benches/benchmarks/validity_checks.rs

@@ -45,11 +45,7 @@ fn setup_dkg(
     let me = validators[validator].clone();
     PubliclyVerifiableDkg::new(
         &validators,
-        &DkgParams {
-            tau: 0,
-            security_threshold: shares_num / 3,
-            shares_num,
-        },
+        &DkgParams::new(0, shares_num / 3, shares_num).unwrap(),
         &me,
     )
     .expect("Setup failed")

ferveo/examples/bench_primitives_size.rs

@@ -80,11 +80,7 @@ fn setup_dkg(
     let me = validators[validator].clone();
     PubliclyVerifiableDkg::new(
         &validators,
-        &DkgParams {
-            tau: 0,
-            security_threshold,
-            shares_num,
-        },
+        &DkgParams::new(0, security_threshold, shares_num).unwrap(),
         &me,
     )
     .expect("Setup failed")