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 17 package com.google.crypto.tink.signature; 18 19 import com.google.crypto.tink.Key; 20 import com.google.crypto.tink.PrivateKey; 21 import com.google.crypto.tink.util.Bytes; 22 import com.google.errorprone.annotations.Immutable; 23 import javax.annotation.Nullable; 24 25 /** 26 * A {@link SignaturePrivateKey} represents a digital signature primitive, which consists of a sign 27 * and a verify function. 28 * 29 * <p>The verify function is only available indirectly, with {@link #getPublicKey}. 30 */ 31 @Immutable 32 public abstract class SignaturePrivateKey extends Key implements PrivateKey { 33 /** 34 * Returns the {@link SignaturePublicKey}, which contains the verify function of the digital 35 * signature primitive. 36 */ 37 @Override getPublicKey()38 public abstract SignaturePublicKey getPublicKey(); 39 40 /** 41 * Returns a {@link Bytes} instance which is prefixed to every signature. 42 * 43 * <p>Returns the same as {@code getPublicKey().getOutputPrefix()}. 44 */ getOutputPrefix()45 public final Bytes getOutputPrefix() { 46 return getPublicKey().getOutputPrefix(); 47 } 48 49 @Override 50 @Nullable getIdRequirementOrNull()51 public Integer getIdRequirementOrNull() { 52 return getPublicKey().getIdRequirementOrNull(); 53 } 54 55 /** 56 * Returns the parameters of this key. 57 * 58 * <p>Returns the same as {@code getPublicKey().getParameters()}. 59 */ 60 @Override getParameters()61 public SignatureParameters getParameters() { 62 return getPublicKey().getParameters(); 63 } 64 } 65