Remove threshold check

pkg/threshcrypto/pseudo.go

@@ -29,7 +29,7 @@ func pseudorandomStream(seed int64) cipher.Stream {
 // Intended for testing purposes and assuming a static membership known to all nodes,
 // NodePseudo can be invoked by each Node independently (specifying the same seed, e.g. DefaultPseudoSeed)
 // and generates the same set of keys for the whole system at each node, obviating the exchange of public keys.
-func TBLSPseudo(nodes []t.NodeID, nByz, threshold int, ownID t.NodeID, seed int64) (ThreshCrypto, error) {
+func TBLSPseudo(nodes []t.NodeID, threshold int, ownID t.NodeID, seed int64) (ThreshCrypto, error) {
 	// Create a new pseudorandom source from the given seed.
 	randomness := pseudorandomStream(seed)
 
@@ -38,10 +38,7 @@ func TBLSPseudo(nodes []t.NodeID, nByz, threshold int, ownID t.NodeID, seed int6
 		return nil, fmt.Errorf("own node ID not in node list")
 	}
 
-	tcInstances, err := TBLS12381Keygen(nByz, threshold, nodes, randomness)
-	if err != nil {
-		return nil, err
-	}
+	tcInstances := TBLS12381Keygen(threshold, nodes, randomness)
 
 	return tcInstances[idx], nil
 }

pkg/threshcrypto/tbls.go

@@ -45,11 +45,8 @@ func tbls12381Scheme() (pairing.Suite, sign.ThresholdScheme, kyber.Group, kyber.
 // TBLS12381Keygen constructs a set TBLSInst for a given set of member nodes and threshold T
 // with nByz byzantine nodes, using the BLS12-381 pairing, with signatures being points on curve G1,
 // and keys points on curve G2.
-func TBLS12381Keygen(nByz, T int, members []t.NodeID, randSource cipher.Stream) ([]*TBLSInst, error) {
+func TBLS12381Keygen(T int, members []t.NodeID, randSource cipher.Stream) []*TBLSInst {
 	N := len(members)
-	if !(nByz < (N+1)/2 && nByz >= 0 && T > nByz) {
-		return nil, fmt.Errorf("(T, N)-threshold BLS requires 0 <= nByz < N/2, and T > nByz, where nByz is the number of byzantine participants")
-	}
 
 	pairing, scheme, sigGroup, keyGroup := tbls12381Scheme()
 
@@ -74,7 +71,7 @@ func TBLS12381Keygen(nByz, T int, members []t.NodeID, randSource cipher.Stream)
 		}
 	}
 
-	return instances, nil
+	return instances
 }
 
 // MarshalTo writes the properties of a TBLSInst to an io.Writer.

pkg/threshcrypto/tbls_test.go

@@ -15,8 +15,7 @@ func TestTBLSHappySmoke(t *testing.T) {
 	N := 5
 	T := 3
 
-	keys, err := keygen(T-1, T, N)
-	assert.NoError(t, err)
+	keys := keygen(T-1, T, N)
 
 	data := [][]byte{{1, 2, 3, 4, 5}, {4, 2}}
 
@@ -52,8 +51,7 @@ func TestTBLSSadSmoke(t *testing.T) {
 	N := 5
 	T := 3
 
-	keys, err := keygen(T-1, T, N)
-	require.NoError(t, err)
+	keys := keygen(T-1, T, N)
 
 	data := [][]byte{{1, 2, 3, 4, 5}, {4, 2}}
 
@@ -66,7 +64,7 @@ func TestTBLSSadSmoke(t *testing.T) {
 	}
 
 	// all of the same share is no good
-	_, err = keys[0].Recover(data, [][]byte{shares[0], shares[0], shares[0]})
+	_, err := keys[0].Recover(data, [][]byte{shares[0], shares[0], shares[0]})
 	assert.Error(t, err)
 
 	// too little shares is no good
@@ -87,8 +85,7 @@ func TestTBLSMarshalling(t *testing.T) {
 	T := N
 	nByz := (N+1)/2 - 1
 
-	keys, err := keygen(nByz, T, N)
-	require.NoError(t, err)
+	keys := keygen(nByz, T, N)
 
 	keys2 := marshalUnmarshalKeys(t, keys)
 
@@ -118,14 +115,14 @@ func TestTBLSMarshalling(t *testing.T) {
 	}
 }
 
-func keygen(nByz, T, N int) ([]*TBLSInst, error) {
+func keygen(nByz, T, N int) []*TBLSInst {
 	members := make([]types.NodeID, N)
 	for i := range members {
 		members[i] = types.NewNodeIDFromInt(i)
 	}
 
 	rand := pseudorandomStream(DefaultPseudoSeed)
-	return TBLS12381Keygen(nByz, T, members, rand)
+	return TBLS12381Keygen(T, members, rand)
 }
 
 func marshalUnmarshalKeys(t *testing.T, src []*TBLSInst) []*TBLSInst {