| // Copyright 2017 Google Inc. |
| // |
| // 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.google.crypto.tink.streamingaead; |
| |
| import com.google.crypto.tink.KeyTemplate; |
| import com.google.crypto.tink.Registry; |
| import com.google.crypto.tink.StreamingAead; |
| import com.google.crypto.tink.internal.KeyTypeManager; |
| import com.google.crypto.tink.internal.PrimitiveFactory; |
| import com.google.crypto.tink.proto.AesCtrHmacStreamingKey; |
| import com.google.crypto.tink.proto.AesCtrHmacStreamingKeyFormat; |
| import com.google.crypto.tink.proto.AesCtrHmacStreamingParams; |
| import com.google.crypto.tink.proto.HashType; |
| import com.google.crypto.tink.proto.HmacParams; |
| import com.google.crypto.tink.proto.KeyData.KeyMaterialType; |
| import com.google.crypto.tink.subtle.AesCtrHmacStreaming; |
| import com.google.crypto.tink.subtle.Random; |
| import com.google.crypto.tink.subtle.Validators; |
| import com.google.protobuf.ByteString; |
| import com.google.protobuf.ExtensionRegistryLite; |
| import com.google.protobuf.InvalidProtocolBufferException; |
| import java.security.GeneralSecurityException; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * This key manager generates new {@code AesCtrHmacStreamingKey} keys and produces new instances of |
| * {@code AesCtrHmacStreaming}. |
| */ |
| public final class AesCtrHmacStreamingKeyManager extends KeyTypeManager<AesCtrHmacStreamingKey> { |
| AesCtrHmacStreamingKeyManager() { |
| super( |
| AesCtrHmacStreamingKey.class, |
| new PrimitiveFactory<StreamingAead, AesCtrHmacStreamingKey>(StreamingAead.class) { |
| @Override |
| public StreamingAead getPrimitive(AesCtrHmacStreamingKey key) |
| throws GeneralSecurityException { |
| return new AesCtrHmacStreaming( |
| key.getKeyValue().toByteArray(), |
| StreamingAeadUtil.toHmacAlgo(key.getParams().getHkdfHashType()), |
| key.getParams().getDerivedKeySize(), |
| StreamingAeadUtil.toHmacAlgo(key.getParams().getHmacParams().getHash()), |
| key.getParams().getHmacParams().getTagSize(), |
| key.getParams().getCiphertextSegmentSize(), |
| /* firstSegmentOffset= */ 0); |
| } |
| }); |
| } |
| |
| /** Minimum tag size in bytes. This provides minimum 80-bit security strength. */ |
| private static final int MIN_TAG_SIZE_IN_BYTES = 10; |
| |
| private static final int NONCE_PREFIX_IN_BYTES = 7; |
| |
| @Override |
| public String getKeyType() { |
| return "type.googleapis.com/google.crypto.tink.AesCtrHmacStreamingKey"; |
| } |
| |
| @Override |
| public int getVersion() { |
| return 0; |
| } |
| |
| @Override |
| public KeyMaterialType keyMaterialType() { |
| return KeyMaterialType.SYMMETRIC; |
| } |
| |
| @Override |
| public void validateKey(AesCtrHmacStreamingKey key) throws GeneralSecurityException { |
| Validators.validateVersion(key.getVersion(), getVersion()); |
| if (key.getKeyValue().size() < 16) { |
| throw new GeneralSecurityException("key_value must have at least 16 bytes"); |
| } |
| if (key.getKeyValue().size() < key.getParams().getDerivedKeySize()) { |
| throw new GeneralSecurityException( |
| "key_value must have at least as many bits as derived keys"); |
| } |
| validateParams(key.getParams()); |
| } |
| |
| @Override |
| public AesCtrHmacStreamingKey parseKey(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return AesCtrHmacStreamingKey.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public KeyFactory<AesCtrHmacStreamingKeyFormat, AesCtrHmacStreamingKey> keyFactory() { |
| return new KeyFactory<AesCtrHmacStreamingKeyFormat, AesCtrHmacStreamingKey>( |
| AesCtrHmacStreamingKeyFormat.class) { |
| @Override |
| public void validateKeyFormat(AesCtrHmacStreamingKeyFormat format) |
| throws GeneralSecurityException { |
| if (format.getKeySize() < 16) { |
| throw new GeneralSecurityException("key_size must be at least 16 bytes"); |
| } |
| validateParams(format.getParams()); |
| } |
| |
| @Override |
| public AesCtrHmacStreamingKeyFormat parseKeyFormat(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return AesCtrHmacStreamingKeyFormat.parseFrom( |
| byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public AesCtrHmacStreamingKey createKey(AesCtrHmacStreamingKeyFormat format) |
| throws GeneralSecurityException { |
| return AesCtrHmacStreamingKey.newBuilder() |
| .setKeyValue(ByteString.copyFrom(Random.randBytes(format.getKeySize()))) |
| .setParams(format.getParams()) |
| .setVersion(getVersion()) |
| .build(); |
| } |
| |
| @Override |
| public Map<String, KeyFactory.KeyFormat<AesCtrHmacStreamingKeyFormat>> keyFormats() |
| throws GeneralSecurityException { |
| Map<String, KeyFactory.KeyFormat<AesCtrHmacStreamingKeyFormat>> result = new HashMap<>(); |
| result.put( |
| "AES128_CTR_HMAC_SHA256_4KB", |
| new KeyFactory.KeyFormat<>( |
| createKeyFormat(16, HashType.SHA256, 16, HashType.SHA256, 32, 4096), |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "AES128_CTR_HMAC_SHA256_1MB", |
| new KeyFactory.KeyFormat<>( |
| createKeyFormat(16, HashType.SHA256, 16, HashType.SHA256, 32, 1 << 20), |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "AES256_CTR_HMAC_SHA256_4KB", |
| new KeyFactory.KeyFormat<>( |
| createKeyFormat(32, HashType.SHA256, 32, HashType.SHA256, 32, 4096), |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "AES256_CTR_HMAC_SHA256_1MB", |
| new KeyFactory.KeyFormat<>( |
| createKeyFormat(32, HashType.SHA256, 32, HashType.SHA256, 32, 1 << 20), |
| KeyTemplate.OutputPrefixType.RAW)); |
| return Collections.unmodifiableMap(result); |
| } |
| }; |
| } |
| |
| private static void validateParams(AesCtrHmacStreamingParams params) |
| throws GeneralSecurityException { |
| Validators.validateAesKeySize(params.getDerivedKeySize()); |
| if (params.getHkdfHashType() == HashType.UNKNOWN_HASH) { |
| throw new GeneralSecurityException("unknown HKDF hash type"); |
| } |
| if (params.getHmacParams().getHash() == HashType.UNKNOWN_HASH) { |
| throw new GeneralSecurityException("unknown HMAC hash type"); |
| } |
| validateHmacParams(params.getHmacParams()); |
| |
| if (params.getCiphertextSegmentSize() |
| < params.getDerivedKeySize() |
| + params.getHmacParams().getTagSize() |
| + 2 |
| + NONCE_PREFIX_IN_BYTES) { |
| throw new GeneralSecurityException( |
| "ciphertext_segment_size must be at least (derived_key_size + tag_size + " |
| + "NONCE_PREFIX_IN_BYTES + 2)"); |
| } |
| } |
| |
| private static void validateHmacParams(HmacParams params) throws GeneralSecurityException { |
| if (params.getTagSize() < MIN_TAG_SIZE_IN_BYTES) { |
| throw new GeneralSecurityException("tag size too small"); |
| } |
| switch (params.getHash()) { |
| case SHA1: |
| if (params.getTagSize() > 20) { |
| throw new GeneralSecurityException("tag size too big"); |
| } |
| break; |
| case SHA256: |
| if (params.getTagSize() > 32) { |
| throw new GeneralSecurityException("tag size too big"); |
| } |
| break; |
| case SHA512: |
| if (params.getTagSize() > 64) { |
| throw new GeneralSecurityException("tag size too big"); |
| } |
| break; |
| default: |
| throw new GeneralSecurityException("unknown hash type"); |
| } |
| } |
| |
| public static void register(boolean newKeyAllowed) throws GeneralSecurityException { |
| Registry.registerKeyManager(new AesCtrHmacStreamingKeyManager(), newKeyAllowed); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AesCtrHmacStreaming keys with the |
| * following parameters: |
| * <ul> |
| * <li>Size of the main key: 16 bytes |
| * <li>HKDF algo: HMAC-SHA256 |
| * <li>Size of AES-CTR derived keys: 16 bytes |
| * <li>Tag algo: HMAC-SHA256 |
| * <li>Tag size: 32 bytes |
| * <li>Ciphertext segment size: 4096 |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("AES128_CTR_HMAC_SHA256_4KB")} |
| */ |
| @Deprecated |
| public static final KeyTemplate aes128CtrHmacSha2564KBTemplate() { |
| return createKeyTemplate(16, HashType.SHA256, 16, HashType.SHA256, 32, 4096); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AesCtrHmacStreaming keys with the |
| * following parameters: |
| * <ul> |
| * <li>Size of the main key: 16 bytes |
| * <li>HKDF algo: HMAC-SHA256 |
| * <li>Size of AES-CTR derived keys: 16 bytes |
| * <li>Tag algo: HMAC-SHA256 |
| * <li>Tag size: 32 bytes |
| * <li>Ciphertext segment size: 1MB |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("AES128_CTR_HMAC_SHA256_1MB")} |
| */ |
| @Deprecated |
| public static final KeyTemplate aes128CtrHmacSha2561MBTemplate() { |
| return createKeyTemplate(16, HashType.SHA256, 16, HashType.SHA256, 32, 1 << 20); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AesCtrHmacStreaming keys with the |
| * following parameters: |
| * <ul> |
| * <li>Size of the main key: 32 bytes |
| * <li>HKDF algo: HMAC-SHA256 |
| * <li>Size of AES-CTR derived keys: 32 bytes |
| * <li>Tag algo: HMAC-SHA256 |
| * <li>Tag size: 32 bytes |
| * <li>Ciphertext segment size: 4096 |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("AES256_CTR_HMAC_SHA256_4KB")} |
| */ |
| @Deprecated |
| public static final KeyTemplate aes256CtrHmacSha2564KBTemplate() { |
| return createKeyTemplate(32, HashType.SHA256, 32, HashType.SHA256, 32, 4096); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of AesCtrHmacStreaming keys with the |
| * following parameters: |
| * <ul> |
| * <li>Size of the main key: 32 bytes |
| * <li>HKDF algo: HMAC-SHA256 |
| * <li>Size of AES-CTR derived keys: 32 bytes |
| * <li>Tag algo: HMAC-SHA256 |
| * <li>Tag size: 32 bytes |
| * <li>Ciphertext segment size: 1MB |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("AES256_CTR_HMAC_SHA256_1MB")} |
| */ |
| @Deprecated |
| public static final KeyTemplate aes256CtrHmacSha2561MBTemplate() { |
| return createKeyTemplate(32, HashType.SHA256, 32, HashType.SHA256, 32, 1 << 20); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} containing a {@link AesCtrHmacStreamingKeyFormat} with some |
| * specified parameters. |
| */ |
| private static KeyTemplate createKeyTemplate( |
| int mainKeySize, |
| HashType hkdfHashType, |
| int derivedKeySize, |
| HashType macHashType, |
| int tagSize, |
| int ciphertextSegmentSize) { |
| AesCtrHmacStreamingKeyFormat format = |
| createKeyFormat( |
| mainKeySize, hkdfHashType, derivedKeySize, macHashType, tagSize, ciphertextSegmentSize); |
| return KeyTemplate.create( |
| new AesCtrHmacStreamingKeyManager().getKeyType(), |
| format.toByteArray(), |
| KeyTemplate.OutputPrefixType.RAW); |
| } |
| |
| private static AesCtrHmacStreamingKeyFormat createKeyFormat( |
| int mainKeySize, |
| HashType hkdfHashType, |
| int derivedKeySize, |
| HashType macHashType, |
| int tagSize, |
| int ciphertextSegmentSize) { |
| HmacParams hmacParams = |
| HmacParams.newBuilder().setHash(macHashType).setTagSize(tagSize).build(); |
| AesCtrHmacStreamingParams params = |
| AesCtrHmacStreamingParams.newBuilder() |
| .setCiphertextSegmentSize(ciphertextSegmentSize) |
| .setDerivedKeySize(derivedKeySize) |
| .setHkdfHashType(hkdfHashType) |
| .setHmacParams(hmacParams) |
| .build(); |
| return AesCtrHmacStreamingKeyFormat.newBuilder() |
| .setParams(params) |
| .setKeySize(mainKeySize) |
| .build(); |
| } |
| } |
