1*e7b1675dSTing-Kang Chang// Copyright 2022 Google LLC 2*e7b1675dSTing-Kang Chang// 3*e7b1675dSTing-Kang Chang// Licensed under the Apache License, Version 2.0 (the "License"); 4*e7b1675dSTing-Kang Chang// you may not use this file except in compliance with the License. 5*e7b1675dSTing-Kang Chang// You may obtain a copy of the License at 6*e7b1675dSTing-Kang Chang// 7*e7b1675dSTing-Kang Chang// http://www.apache.org/licenses/LICENSE-2.0 8*e7b1675dSTing-Kang Chang// 9*e7b1675dSTing-Kang Chang// Unless required by applicable law or agreed to in writing, software 10*e7b1675dSTing-Kang Chang// distributed under the License is distributed on an "AS IS" BASIS, 11*e7b1675dSTing-Kang Chang// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12*e7b1675dSTing-Kang Chang// See the License for the specific language governing permissions and 13*e7b1675dSTing-Kang Chang// limitations under the License. 14*e7b1675dSTing-Kang Chang// 15*e7b1675dSTing-Kang Chang//////////////////////////////////////////////////////////////////////////////// 16*e7b1675dSTing-Kang Chang 17*e7b1675dSTing-Kang Changpackage signature 18*e7b1675dSTing-Kang Chang 19*e7b1675dSTing-Kang Changimport ( 20*e7b1675dSTing-Kang Chang "fmt" 21*e7b1675dSTing-Kang Chang "math/big" 22*e7b1675dSTing-Kang Chang 23*e7b1675dSTing-Kang Chang internal "github.com/google/tink/go/internal/signature" 24*e7b1675dSTing-Kang Chang commonpb "github.com/google/tink/go/proto/common_go_proto" 25*e7b1675dSTing-Kang Chang) 26*e7b1675dSTing-Kang Chang 27*e7b1675dSTing-Kang Changfunc bytesToBigInt(val []byte) *big.Int { 28*e7b1675dSTing-Kang Chang return new(big.Int).SetBytes(val) 29*e7b1675dSTing-Kang Chang} 30*e7b1675dSTing-Kang Chang 31*e7b1675dSTing-Kang Changfunc validateRSAPubKeyParams(h commonpb.HashType, modSizeBits int, pubExponent []byte) error { 32*e7b1675dSTing-Kang Chang if err := internal.HashSafeForSignature(hashName(h)); err != nil { 33*e7b1675dSTing-Kang Chang return err 34*e7b1675dSTing-Kang Chang } 35*e7b1675dSTing-Kang Chang if err := internal.RSAValidModulusSizeInBits(modSizeBits); err != nil { 36*e7b1675dSTing-Kang Chang return err 37*e7b1675dSTing-Kang Chang } 38*e7b1675dSTing-Kang Chang e := bytesToBigInt(pubExponent) 39*e7b1675dSTing-Kang Chang if !e.IsInt64() { 40*e7b1675dSTing-Kang Chang return fmt.Errorf("public exponent can't fit in a 64 bit integer") 41*e7b1675dSTing-Kang Chang } 42*e7b1675dSTing-Kang Chang return internal.RSAValidPublicExponent(int(e.Int64())) 43*e7b1675dSTing-Kang Chang} 44*e7b1675dSTing-Kang Chang 45*e7b1675dSTing-Kang Changfunc hashName(h commonpb.HashType) string { 46*e7b1675dSTing-Kang Chang return commonpb.HashType_name[int32(h)] 47*e7b1675dSTing-Kang Chang} 48