Java tutorial
/** * Copyright Microsoft Corporation * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.microsoft.azure.storage.queue; import javax.crypto.Cipher; import javax.crypto.KeyGenerator; import javax.crypto.SecretKey; import javax.crypto.spec.IvParameterSpec; import javax.crypto.spec.SecretKeySpec; import org.apache.commons.lang3.tuple.Pair; import com.microsoft.azure.keyvault.core.IKey; import com.microsoft.azure.keyvault.core.IKeyResolver; import com.microsoft.azure.storage.Constants; import com.microsoft.azure.storage.StorageErrorCodeStrings; import com.microsoft.azure.storage.StorageException; import com.microsoft.azure.storage.core.Base64; import com.microsoft.azure.storage.core.EncryptionAgent; import com.microsoft.azure.storage.core.EncryptionAlgorithm; import com.microsoft.azure.storage.core.EncryptionData; import com.microsoft.azure.storage.core.SR; import com.microsoft.azure.storage.core.Utility; import com.microsoft.azure.storage.core.WrappedContentKey; /** * Represents a queue encryption policy that is used to perform envelope encryption/decryption of Azure queue messages. */ public final class QueueEncryptionPolicy { /** * An object of type {@link IKey} that is used to wrap/unwrap the content key during encryption. */ public IKey keyWrapper; /** * The {@link IKeyResolver} used to select the correct key for decrypting existing queue messages. */ public IKeyResolver keyResolver; /** * Initializes a new instance of the {@link QueueEncryptionPolicy} class with the specified key and resolver. * <p> * If the generated policy is intended to be used for encryption, users are expected to provide a key at the * minimum. The absence of key will cause an exception to be thrown during encryption. If the generated policy is * intended to be used for decryption, users can provide a keyResolver. The client library will - 1. Invoke the key * resolver if specified to get the key. 2. If resolver is not specified but a key is specified, match the key id on * the key and use it. * * @param key * An object of type {@link IKey} that is used to wrap/unwrap the content encryption key. * @param keyResolver * The key resolver used to select the correct key for decrypting existing queue messages. */ public QueueEncryptionPolicy(IKey key, IKeyResolver keyResolver) { this.keyWrapper = key; this.keyResolver = keyResolver; } /** * Gets the {@link IKey} that is used to wrap/unwrap the content key during encryption. * * @return An {@link IKey} object. */ public IKey getKey() { return this.keyWrapper; } /** * Gets the key resolver used to select the correct key for decrypting existing queue messages. * * @return A resolver that returns an {@link SymmetricKey} given a keyId. */ public IKeyResolver getKeyResolver() { return this.keyResolver; } /** * Sets the {@link IKey} that is used to wrap/unwrap the content key during encryption. * * @param key * An {@link IKey} object. */ public void setKey(IKey key) { this.keyWrapper = key; } /** * Sets the key resolver used to select the correct key for decrypting existing queue messages. * * @param keyResolver * A resolver that returns an {@link IKey} given a keyId. */ public void setKeyResolver(IKeyResolver keyResolver) { this.keyResolver = keyResolver; } /** * Return an encrypted base64 encoded message along with encryption related metadata given a plain text message. * * @param inputMessage * The input message in bytes. * @return The encrypted message that will be uploaded to the service. * @throws StorageException * An exception representing any error which occurred during the operation. */ String encryptMessage(byte[] inputMessage) throws StorageException { Utility.assertNotNull("inputMessage", inputMessage); if (this.keyWrapper == null) { throw new IllegalArgumentException(SR.KEY_MISSING); } CloudQueueEncryptedMessage encryptedMessage = new CloudQueueEncryptedMessage(); EncryptionData encryptionData = new EncryptionData(); encryptionData.setEncryptionAgent(new EncryptionAgent(Constants.EncryptionConstants.ENCRYPTION_PROTOCOL_V1, EncryptionAlgorithm.AES_CBC_256)); try { KeyGenerator keyGen = KeyGenerator.getInstance("AES"); keyGen.init(256); Cipher myAes = Cipher.getInstance("AES/CBC/PKCS5Padding"); SecretKey aesKey = keyGen.generateKey(); myAes.init(Cipher.ENCRYPT_MODE, aesKey); // Wrap key Pair<byte[], String> encryptedKey = this.keyWrapper .wrapKeyAsync(aesKey.getEncoded(), null /* algorithm */).get(); encryptionData.setWrappedContentKey(new WrappedContentKey(this.keyWrapper.getKid(), encryptedKey.getKey(), encryptedKey.getValue())); encryptedMessage.setEncryptedMessageContents( new String(Base64.encode(myAes.doFinal(inputMessage, 0, inputMessage.length)))); encryptionData.setContentEncryptionIV(myAes.getIV()); encryptedMessage.setEncryptionData(encryptionData); return encryptedMessage.serialize(); } catch (Exception e) { throw StorageException.translateClientException(e); } } /** * Returns a plain text message given an encrypted message. * * @param inputMessage * The encrypted message. * @param requireEncryption * A value to indicate that the data read from the server should be encrypted. * @return The plain text message bytes. * @throws StorageException * An exception representing any error which occurred during the operation. */ byte[] decryptMessage(String inputMessage, Boolean requireEncryption) throws StorageException { Utility.assertNotNull("inputMessage", inputMessage); try { CloudQueueEncryptedMessage encryptedMessage = CloudQueueEncryptedMessage.deserialize(inputMessage); if (requireEncryption != null && requireEncryption && encryptedMessage.getEncryptionData() == null) { throw new StorageException(StorageErrorCodeStrings.DECRYPTION_ERROR, SR.ENCRYPTION_DATA_NOT_PRESENT_ERROR, null); } if (encryptedMessage.getEncryptionData() != null) { EncryptionData encryptionData = encryptedMessage.getEncryptionData(); Utility.assertNotNull("contentEncryptionIV", encryptionData.getContentEncryptionIV()); Utility.assertNotNull("encryptedKey", encryptionData.getWrappedContentKey().getEncryptedKey()); // Throw if the encryption protocol on the message doesn't match the version that this client library understands // and is able to decrypt. if (!Constants.EncryptionConstants.ENCRYPTION_PROTOCOL_V1 .equals(encryptionData.getEncryptionAgent().getProtocol())) { throw new StorageException(StorageErrorCodeStrings.DECRYPTION_ERROR, SR.ENCRYPTION_PROTOCOL_VERSION_INVALID, null); } // Throw if neither the key nor the key resolver are set. if (this.keyWrapper == null && this.keyResolver == null) { throw new StorageException(StorageErrorCodeStrings.DECRYPTION_ERROR, SR.KEY_AND_RESOLVER_MISSING, null); } byte[] contentEncryptionKey = null; // 1. Invoke the key resolver if specified to get the key. If the resolver is specified but does not have a // mapping for the key id, an error should be thrown. This is important for key rotation scenario. // 2. If resolver is not specified but a key is specified, match the key id on the key and and use it. // Calling UnwrapKeyAsync synchronously is fine because for the storage client scenario, unwrap happens // locally. No service call is made. if (this.keyResolver != null) { IKey keyEncryptionKey = this.keyResolver .resolveKeyAsync(encryptionData.getWrappedContentKey().getKeyId()).get(); Utility.assertNotNull("keyEncryptionKey", keyEncryptionKey); contentEncryptionKey = keyEncryptionKey .unwrapKeyAsync(encryptionData.getWrappedContentKey().getEncryptedKey(), encryptionData.getWrappedContentKey().getAlgorithm()) .get(); } else { if (encryptionData.getWrappedContentKey().getKeyId().equals(this.keyWrapper.getKid())) { contentEncryptionKey = this.keyWrapper .unwrapKeyAsync(encryptionData.getWrappedContentKey().getEncryptedKey(), encryptionData.getWrappedContentKey().getAlgorithm()) .get(); } else { throw new StorageException(StorageErrorCodeStrings.DECRYPTION_ERROR, SR.KEY_MISMATCH, null); } } switch (encryptionData.getEncryptionAgent().getEncryptionAlgorithm()) { case AES_CBC_256: Cipher myAes = Cipher.getInstance("AES/CBC/PKCS5Padding"); IvParameterSpec ivParameterSpec = new IvParameterSpec(encryptionData.getContentEncryptionIV()); SecretKey keySpec = new SecretKeySpec(contentEncryptionKey, 0, contentEncryptionKey.length, "AES"); myAes.init(Cipher.DECRYPT_MODE, keySpec, ivParameterSpec); byte[] src = Base64.decode(encryptedMessage.getEncryptedMessageContents()); return myAes.doFinal(src, 0, src.length); default: throw new StorageException(StorageErrorCodeStrings.DECRYPTION_ERROR, SR.INVALID_ENCRYPTION_ALGORITHM, null); } } else { return Base64.decode(encryptedMessage.getEncryptedMessageContents()); } } catch (StorageException ex) { throw ex; } catch (Exception ex) { throw new StorageException(StorageErrorCodeStrings.DECRYPTION_ERROR, SR.DECRYPTION_LOGIC_ERROR, ex); } } }