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 streamingprf_test 18 19import ( 20 "crypto/sha256" 21 "crypto/sha512" 22 "testing" 23 24 commonpb "github.com/google/tink/go/proto/common_go_proto" 25) 26 27const hkdfPRFTypeURL = "type.googleapis.com/google.crypto.tink.HkdfPrfKey" 28 29// limitFromHash returns the maximum output bytes from a HKDF using hash. 30func limitFromHash(t *testing.T, hash commonpb.HashType) (limit int) { 31 t.Helper() 32 switch hash { 33 case commonpb.HashType_SHA256: 34 limit = sha256.Size * 255 35 case commonpb.HashType_SHA512: 36 limit = sha512.Size * 255 37 default: 38 t.Fatalf("unsupported hash type: %s", hash.String()) 39 } 40 return 41} 42