new common and ecdsa packages

bls.go

@@ -90,6 +90,14 @@ type blsBLS12381Algo struct {
 	algo sign.SigningAlgorithm
 }
 
+// init the BLS12-381 curve context
+func init() {
+	// register the BLS context on the BLS 12-381 curve instance in the `sign` package
+	if err := sign.RegisterSigner(sign.BLSBLS12381, &blsBLS12381Algo{algo: sign.BLSBLS12381}); err != nil {
+		panic(err)
+	}
+}
+
 // NewExpandMsgXOFKMAC128 returns a new expand_message_xof instance for
 // the hash-to-curve function, hashing data to G1 on BLS12 381.
 // This instance must only be used to generate signatures (and not PoP),

bls_test.go

@@ -33,15 +33,16 @@
 
 	"github.com/onflow/crypto/hash"
 	"github.com/onflow/crypto/sign"
+	"github.com/onflow/crypto/sign/internal"
 )
 
 // TestBLSMainMethods is a sanity check of main signature scheme methods (keyGen, sign, verify)
 func TestBLSMainMethods(t *testing.T) {
 	// test the key generation seed lengths
-	testKeyGenSeed(t, sign.BLSBLS12381, KeyGenSeedMinLen, KeyGenSeedMaxLen)
+	internal.TestKeyGenSeed(t, sign.BLSBLS12381, KeyGenSeedMinLen, KeyGenSeedMaxLen)
 	// test the consistency with different inputs
 	hasher := NewExpandMsgXOFKMAC128("test tag")
-	testGenSignVerify(t, sign.BLSBLS12381, hasher)
+	internal.TestGenSignVerify(t, sign.BLSBLS12381, hasher)
 
 	// specific signature test for BLS:
 	// Test a signature with a point encoded with a coordinate x not reduced mod p.

common/common.go

@@ -0,0 +1,57 @@
+/*
+ * Flow Crypto
+ *
+ * Copyright Flow Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package common
+
+import (
+	"errors"
+
+	"github.com/onflow/crypto/internal"
+)
+
+// IsInvalidInputsError checks if the input error is of an invalidInputsError type
+// invalidInputsError is returned when the API is provided invalid inputs.
+// Some specific errors are assigned specific sentinel errors for a simpler error check
+// while the remaining input errors trigger an invalidInputsError.
+func IsInvalidInputsError(err error) bool {
+	var target *internal.InvalidInputsError
+	return errors.As(err, &target)
+}
+
+// InvalidInputsErrorf constructs a new invalidInputsError
+var InvalidInputsErrorf = internal.InvalidInputsErrorf
+
+// IsNilHasherError checks if the input error wraps the internal errNilHasher,
+// which is returned when a nil hasher is used.
+func IsNilHasherError(err error) bool {
+	return errors.Is(err, ErrNilHasher)
+}
+
+// ErrNilHasher is returned when a nil hasher is used
+var ErrNilHasher = internal.ErrNilHasher
+
+// IsInvalidHasherSizeError checks if the input error is of an invalidHasherSizeError type.
+// invalidHasherSizeError is an error returned when a crypto API is called with a hasher
+// with an output size not suited with the cryptographic operation.
+func IsInvalidHasherSizeError(err error) bool {
+	var target *internal.InvalidHasherSizeError
+	return errors.As(err, &target)
+}
+
+// InvalidHasherSizeErrorf constructs a new invalidHasherSizeError
+var InvalidHasherSizeErrorf = internal.InvalidHasherSizeErrorf

internal/internal.go

@@ -0,0 +1,80 @@
+/*
+ * Flow Crypto
+ *
+ * Copyright Flow Foundation.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *   http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package internal
+
+import (
+	"crypto/rand"
+	"errors"
+	"fmt"
+)
+
+// Minimum targeted bits of security.
+// This is used as a reference but it doesn't mean all implemented primitives provide this minimum.
+const SecurityBits = 128
+
+// TODO: update this code to make sure
+// the function isn't removed by the compiler
+// https://github.com/golang/go/issues/21865
+func Overwrite(data []byte) {
+	_, err := rand.Read(data) // checking err is enough
+	if err != nil {
+		// zero the buffer if randomizing failed
+		for i := 0; i < len(data); i++ {
+			data[i] = 0
+		}
+	}
+}
+
+// InvalidInputsError is an error returned when a crypto API receives invalid inputs.
+// It allows a function caller differentiate unexpected program errors from errors caused by
+// invalid inputs.
+type InvalidInputsError struct {
+	error
+}
+
+func (e InvalidInputsError) Unwrap() error {
+	return e.error
+}
+
+// InvalidHasherSizeError is an error returned when a crypto API is called with a hasher
+// with an output size not suited with the cryptographic operation.
+type InvalidHasherSizeError struct {
+	error
+}
+
+func (e InvalidHasherSizeError) Unwrap() error {
+	return e.error
+}
+
+// ErrNilHasher is returned when a nil hasher is used
+var ErrNilHasher = errors.New("hasher cannot be nil")
+
+// InvalidInputsErrorf constructs a new InvalidInputsError
+func InvalidInputsErrorf(msg string, args ...interface{}) error {
+	return &InvalidInputsError{
+		error: fmt.Errorf(msg, args...),
+	}
+}
+
+// InvalidHasherSizeErrorf constructs a new InvalidHasherSizeError
+func InvalidHasherSizeErrorf(msg string, args ...interface{}) error {
+	return &InvalidHasherSizeError{
+		error: fmt.Errorf(msg, args...),
+	}
+}