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| 1 | +/* |
| 2 | + * Copyright 2019 Amazon.com, Inc. or its affiliates. All Rights Reserved. |
| 3 | + * |
| 4 | + * Licensed under the Apache License, Version 2.0 (the "License"). You may not use this file except |
| 5 | + * in compliance with the License. A copy of the License is located at |
| 6 | + * |
| 7 | + * http://aws.amazon.com/apache2.0 |
| 8 | + * |
| 9 | + * or in the "license" file accompanying this file. This file is distributed on an "AS IS" BASIS, |
| 10 | + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the License for the |
| 11 | + * specific language governing permissions and limitations under the License. |
| 12 | + */ |
| 13 | + |
| 14 | +package com.amazonaws.encryptionsdk.keyrings; |
| 15 | + |
| 16 | +import com.amazonaws.encryptionsdk.CryptoAlgorithm; |
| 17 | + |
| 18 | +import javax.crypto.SecretKey; |
| 19 | +import java.security.PublicKey; |
| 20 | +import java.util.Collections; |
| 21 | +import java.util.HashMap; |
| 22 | +import java.util.Map; |
| 23 | +import java.util.Objects; |
| 24 | + |
| 25 | +import static java.util.Objects.requireNonNull; |
| 26 | +import static org.apache.commons.lang3.Validate.isTrue; |
| 27 | + |
| 28 | +/** |
| 29 | + * Contains the cryptographic materials needed for a decryption operation with Keyrings. |
| 30 | + */ |
| 31 | +public final class DecryptionMaterials { |
| 32 | + private final CryptoAlgorithm algorithmSuite; |
| 33 | + private SecretKey plaintextDataKey; |
| 34 | + private final PublicKey verificationKey; |
| 35 | + private final Map<String, String> encryptionContext; |
| 36 | + private final KeyringTrace keyringTrace; |
| 37 | + |
| 38 | + private DecryptionMaterials(Builder b) { |
| 39 | + requireNonNull(b.algorithmSuite, "algorithmSuite is required"); |
| 40 | + requireNonNull(b.keyringTrace, "keyringTrace is required"); |
| 41 | + requireNonNull(b.encryptionContext, "encryptionContext is required"); |
| 42 | + validatePlaintextDataKey(b.algorithmSuite, b.plaintextDataKey); |
| 43 | + validateVerificationKey(b.algorithmSuite, b.verificationKey); |
| 44 | + |
| 45 | + algorithmSuite = b.algorithmSuite; |
| 46 | + plaintextDataKey = b.plaintextDataKey; |
| 47 | + verificationKey = b.verificationKey; |
| 48 | + encryptionContext = b.encryptionContext; |
| 49 | + keyringTrace = b.keyringTrace; |
| 50 | + } |
| 51 | + |
| 52 | + /** |
| 53 | + * The algorithm suite to use for this decryption operation. |
| 54 | + */ |
| 55 | + public CryptoAlgorithm getAlgorithmSuite() { |
| 56 | + return algorithmSuite; |
| 57 | + } |
| 58 | + |
| 59 | + /** |
| 60 | + * Returns true if a plaintext data key has been populated. |
| 61 | + * |
| 62 | + * @return True if plaintext data key is populated, false otherwise. |
| 63 | + */ |
| 64 | + public boolean hasPlaintextDataKey() { |
| 65 | + return this.plaintextDataKey != null; |
| 66 | + } |
| 67 | + |
| 68 | + /** |
| 69 | + * A data key to be used as input for encryption. |
| 70 | + * |
| 71 | + * @return The plaintext data key. |
| 72 | + * @throws IllegalStateException if plaintext data key has not been populated. |
| 73 | + */ |
| 74 | + public SecretKey getPlaintextDataKey() throws IllegalStateException { |
| 75 | + if (!hasPlaintextDataKey()) { |
| 76 | + throw new IllegalStateException("plaintextDataKey has not been populated"); |
| 77 | + } |
| 78 | + return plaintextDataKey; |
| 79 | + } |
| 80 | + |
| 81 | + /** |
| 82 | + * Sets the plaintext data key. The plaintext data key must not already be populated. |
| 83 | + * |
| 84 | + * @param plaintextDataKey The plaintext data key. |
| 85 | + * @param keyringTraceEntry The keyring trace entry recording this action. |
| 86 | + */ |
| 87 | + public void setPlaintextDataKey(SecretKey plaintextDataKey, KeyringTraceEntry keyringTraceEntry) { |
| 88 | + if (hasPlaintextDataKey()) { |
| 89 | + throw new IllegalStateException("plaintextDataKey was already populated"); |
| 90 | + } |
| 91 | + requireNonNull(plaintextDataKey, "plaintextDataKey is required"); |
| 92 | + requireNonNull(keyringTraceEntry, "keyringTraceEntry is required"); |
| 93 | + validatePlaintextDataKey(algorithmSuite, plaintextDataKey); |
| 94 | + this.plaintextDataKey = plaintextDataKey; |
| 95 | + keyringTrace.add(keyringTraceEntry); |
| 96 | + } |
| 97 | + |
| 98 | + /** |
| 99 | + * Returns true if verification key has been populated. |
| 100 | + * |
| 101 | + * @return True if verification key is populated, false otherwise. |
| 102 | + */ |
| 103 | + public boolean hasVerificationKey() { |
| 104 | + return verificationKey != null; |
| 105 | + } |
| 106 | + |
| 107 | + /** |
| 108 | + * The verification key used for signature verification. |
| 109 | + * |
| 110 | + * @return The verification key. |
| 111 | + * @throws IllegalStateException if a verification key has not been populated. |
| 112 | + */ |
| 113 | + public PublicKey getVerificationKey() throws IllegalStateException { |
| 114 | + if (!hasVerificationKey()) { |
| 115 | + throw new IllegalStateException(String.format( |
| 116 | + "Signature verification is not supported by AlgorithmSuite %s", algorithmSuite.name())); |
| 117 | + } |
| 118 | + return verificationKey; |
| 119 | + } |
| 120 | + |
| 121 | + public Map<String, String> getEncryptionContext() { |
| 122 | + return encryptionContext; |
| 123 | + } |
| 124 | + |
| 125 | + public KeyringTrace getKeyringTrace() { |
| 126 | + return keyringTrace; |
| 127 | + } |
| 128 | + |
| 129 | + @Override |
| 130 | + public boolean equals(Object o) { |
| 131 | + if (this == o) return true; |
| 132 | + if (o == null || getClass() != o.getClass()) return false; |
| 133 | + DecryptionMaterials that = (DecryptionMaterials) o; |
| 134 | + return algorithmSuite == that.algorithmSuite && |
| 135 | + Objects.equals(plaintextDataKey, that.plaintextDataKey) && |
| 136 | + Objects.equals(verificationKey, that.verificationKey) && |
| 137 | + Objects.equals(encryptionContext, that.encryptionContext) && |
| 138 | + Objects.equals(keyringTrace, that.keyringTrace); |
| 139 | + } |
| 140 | + |
| 141 | + @Override |
| 142 | + public int hashCode() { |
| 143 | + return Objects.hash(algorithmSuite, plaintextDataKey, verificationKey, encryptionContext, keyringTrace); |
| 144 | + } |
| 145 | + |
| 146 | + public static Builder newBuilder(CryptoAlgorithm algorithm) { |
| 147 | + return new Builder(algorithm); |
| 148 | + } |
| 149 | + |
| 150 | + public Builder toBuilder() { |
| 151 | + return new Builder(this); |
| 152 | + } |
| 153 | + |
| 154 | + private void validatePlaintextDataKey(CryptoAlgorithm algorithmSuite, SecretKey plaintextDataKey) throws IllegalArgumentException { |
| 155 | + if (plaintextDataKey != null) { |
| 156 | + isTrue(algorithmSuite.getDataKeyLength() == plaintextDataKey.getEncoded().length, |
| 157 | + String.format("Incorrect key length. Expected %s but got %s", |
| 158 | + algorithmSuite.getDataKeyLength(), plaintextDataKey.getEncoded().length)); |
| 159 | + isTrue(algorithmSuite.getDataKeyAlgo().equalsIgnoreCase(plaintextDataKey.getAlgorithm()), |
| 160 | + String.format("Incorrect key algorithm. Expected %s but got %s", |
| 161 | + algorithmSuite.getDataKeyAlgo(), plaintextDataKey.getAlgorithm())); |
| 162 | + } |
| 163 | + } |
| 164 | + |
| 165 | + /** |
| 166 | + * Validates that a verification key is specified if and only if |
| 167 | + * the given algorithm suite supports signature verification. |
| 168 | + */ |
| 169 | + private void validateVerificationKey(CryptoAlgorithm algorithmSuite, PublicKey verificationKey) throws IllegalArgumentException { |
| 170 | + if (algorithmSuite.getTrailingSignatureAlgo() == null && verificationKey != null) { |
| 171 | + throw new IllegalArgumentException( |
| 172 | + String.format("Algorithm Suite %s does not support signature verification", algorithmSuite.name())); |
| 173 | + } else if (algorithmSuite.getTrailingSignatureAlgo() != null && verificationKey == null) { |
| 174 | + throw new IllegalArgumentException( |
| 175 | + String.format("Algorithm %s requires a verification key for signature verification", algorithmSuite.name())); |
| 176 | + } |
| 177 | + } |
| 178 | + |
| 179 | + public static final class Builder { |
| 180 | + private CryptoAlgorithm algorithmSuite; |
| 181 | + private SecretKey plaintextDataKey; |
| 182 | + private PublicKey verificationKey; |
| 183 | + private Map<String, String> encryptionContext = Collections.emptyMap(); |
| 184 | + private KeyringTrace keyringTrace = new KeyringTrace(); |
| 185 | + |
| 186 | + private Builder(CryptoAlgorithm algorithmSuite) { |
| 187 | + this.algorithmSuite = algorithmSuite; |
| 188 | + } |
| 189 | + |
| 190 | + private Builder(DecryptionMaterials result) { |
| 191 | + this.algorithmSuite = result.algorithmSuite; |
| 192 | + this.plaintextDataKey = result.plaintextDataKey; |
| 193 | + this.verificationKey = result.verificationKey; |
| 194 | + this.encryptionContext = result.encryptionContext; |
| 195 | + this.keyringTrace = result.keyringTrace; |
| 196 | + } |
| 197 | + |
| 198 | + public Builder algorithmSuite(CryptoAlgorithm algorithmSuite) { |
| 199 | + this.algorithmSuite = algorithmSuite; |
| 200 | + return this; |
| 201 | + } |
| 202 | + |
| 203 | + public Builder plaintextDataKey(SecretKey plaintextDataKey) { |
| 204 | + this.plaintextDataKey = plaintextDataKey; |
| 205 | + return this; |
| 206 | + } |
| 207 | + |
| 208 | + public Builder verificationKey(PublicKey verificationKey) { |
| 209 | + this.verificationKey = verificationKey; |
| 210 | + return this; |
| 211 | + } |
| 212 | + |
| 213 | + public Builder encryptionContext(Map<String, String> encryptionContext) { |
| 214 | + this.encryptionContext = Collections.unmodifiableMap(new HashMap<>(encryptionContext)); |
| 215 | + return this; |
| 216 | + } |
| 217 | + |
| 218 | + public Builder keyringTrace(KeyringTrace keyringTrace) { |
| 219 | + this.keyringTrace = keyringTrace; |
| 220 | + return this; |
| 221 | + } |
| 222 | + |
| 223 | + public DecryptionMaterials build() { |
| 224 | + return new DecryptionMaterials(this); |
| 225 | + } |
| 226 | + } |
| 227 | +} |
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