1// Copyright 2022 Google LLC 2// 3// Licensed under the Apache License, Version 2.0 (the "License"); 4// you may not use this file except in compliance with the License. 5// You may obtain a copy of the License at 6// 7// http://www.apache.org/licenses/LICENSE-2.0 8// 9// Unless required by applicable law or agreed to in writing, software 10// distributed under the License is distributed on an "AS IS" BASIS, 11// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12// See the License for the specific language governing permissions and 13// limitations under the License. 14// 15//////////////////////////////////////////////////////////////////////////////// 16 17package signature 18 19import ( 20 "fmt" 21 "math/big" 22 23 internal "github.com/google/tink/go/internal/signature" 24 commonpb "github.com/google/tink/go/proto/common_go_proto" 25) 26 27func bytesToBigInt(val []byte) *big.Int { 28 return new(big.Int).SetBytes(val) 29} 30 31func validateRSAPubKeyParams(h commonpb.HashType, modSizeBits int, pubExponent []byte) error { 32 if err := internal.HashSafeForSignature(hashName(h)); err != nil { 33 return err 34 } 35 if err := internal.RSAValidModulusSizeInBits(modSizeBits); err != nil { 36 return err 37 } 38 e := bytesToBigInt(pubExponent) 39 if !e.IsInt64() { 40 return fmt.Errorf("public exponent can't fit in a 64 bit integer") 41 } 42 return internal.RSAValidPublicExponent(int(e.Int64())) 43} 44 45func hashName(h commonpb.HashType) string { 46 return commonpb.HashType_name[int32(h)] 47} 48