| // 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.prf; |
| |
| import com.google.crypto.tink.KeyTemplate; |
| import com.google.crypto.tink.KeyTypeManager; |
| import com.google.crypto.tink.Registry; |
| import com.google.crypto.tink.proto.HashType; |
| import com.google.crypto.tink.proto.HmacPrfKey; |
| import com.google.crypto.tink.proto.HmacPrfKeyFormat; |
| import com.google.crypto.tink.proto.HmacPrfParams; |
| import com.google.crypto.tink.proto.KeyData.KeyMaterialType; |
| import com.google.crypto.tink.subtle.PrfHmacJce; |
| 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.io.IOException; |
| import java.io.InputStream; |
| import java.security.GeneralSecurityException; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| import javax.crypto.spec.SecretKeySpec; |
| |
| /** |
| * This key manager generates new {@code HmacPrfKey} keys and produces new instances of {@code |
| * PrfHmacJce}. |
| */ |
| public final class HmacPrfKeyManager extends KeyTypeManager<HmacPrfKey> { |
| public HmacPrfKeyManager() { |
| super( |
| HmacPrfKey.class, |
| new PrimitiveFactory<Prf, HmacPrfKey>(Prf.class) { |
| @Override |
| public Prf getPrimitive(HmacPrfKey key) throws GeneralSecurityException { |
| HashType hash = key.getParams().getHash(); |
| byte[] keyValue = key.getKeyValue().toByteArray(); |
| SecretKeySpec keySpec = new SecretKeySpec(keyValue, "HMAC"); |
| switch (hash) { |
| case SHA1: |
| return new PrfHmacJce("HMACSHA1", keySpec); |
| case SHA224: |
| return new PrfHmacJce("HMACSHA224", keySpec); |
| case SHA256: |
| return new PrfHmacJce("HMACSHA256", keySpec); |
| case SHA384: |
| return new PrfHmacJce("HMACSHA384", keySpec); |
| case SHA512: |
| return new PrfHmacJce("HMACSHA512", keySpec); |
| default: |
| throw new GeneralSecurityException("unknown hash"); |
| } |
| } |
| }); |
| } |
| |
| /** Minimum key size in bytes. */ |
| private static final int MIN_KEY_SIZE_IN_BYTES = 16; |
| |
| @Override |
| public String getKeyType() { |
| return "type.googleapis.com/google.crypto.tink.HmacPrfKey"; |
| } |
| |
| @Override |
| public int getVersion() { |
| return 0; |
| } |
| |
| @Override |
| public KeyMaterialType keyMaterialType() { |
| return KeyMaterialType.SYMMETRIC; |
| } |
| |
| @Override |
| public void validateKey(HmacPrfKey key) throws GeneralSecurityException { |
| Validators.validateVersion(key.getVersion(), getVersion()); |
| if (key.getKeyValue().size() < MIN_KEY_SIZE_IN_BYTES) { |
| throw new GeneralSecurityException("key too short"); |
| } |
| validateParams(key.getParams()); |
| } |
| |
| @Override |
| public HmacPrfKey parseKey(ByteString byteString) throws InvalidProtocolBufferException { |
| return HmacPrfKey.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| private static void validateParams(HmacPrfParams params) throws GeneralSecurityException { |
| if (params.getHash() != HashType.SHA1 |
| && params.getHash() != HashType.SHA224 |
| && params.getHash() != HashType.SHA256 |
| && params.getHash() != HashType.SHA384 |
| && params.getHash() != HashType.SHA512) { |
| throw new GeneralSecurityException("unknown hash type"); |
| } |
| } |
| |
| @Override |
| public KeyFactory<HmacPrfKeyFormat, HmacPrfKey> keyFactory() { |
| return new KeyFactory<HmacPrfKeyFormat, HmacPrfKey>(HmacPrfKeyFormat.class) { |
| @Override |
| public void validateKeyFormat(HmacPrfKeyFormat format) throws GeneralSecurityException { |
| if (format.getKeySize() < MIN_KEY_SIZE_IN_BYTES) { |
| throw new GeneralSecurityException("key too short"); |
| } |
| validateParams(format.getParams()); |
| } |
| |
| @Override |
| public HmacPrfKeyFormat parseKeyFormat(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return HmacPrfKeyFormat.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public HmacPrfKey createKey(HmacPrfKeyFormat format) { |
| return HmacPrfKey.newBuilder() |
| .setVersion(getVersion()) |
| .setParams(format.getParams()) |
| .setKeyValue(ByteString.copyFrom(Random.randBytes(format.getKeySize()))) |
| .build(); |
| } |
| |
| @Override |
| public HmacPrfKey deriveKey(HmacPrfKeyFormat format, InputStream inputStream) |
| throws GeneralSecurityException { |
| Validators.validateVersion(format.getVersion(), getVersion()); |
| byte[] pseudorandomness = new byte[format.getKeySize()]; |
| try { |
| int read = inputStream.read(pseudorandomness); |
| if (read != format.getKeySize()) { |
| throw new GeneralSecurityException("Not enough pseudorandomness given"); |
| } |
| return HmacPrfKey.newBuilder() |
| .setVersion(getVersion()) |
| .setParams(format.getParams()) |
| .setKeyValue(ByteString.copyFrom(pseudorandomness)) |
| .build(); |
| } catch (IOException e) { |
| throw new GeneralSecurityException("Reading pseudorandomness failed", e); |
| } |
| } |
| |
| @Override |
| public Map<String, KeyFactory.KeyFormat<HmacPrfKeyFormat>> keyFormats() |
| throws GeneralSecurityException { |
| Map<String, KeyFactory.KeyFormat<HmacPrfKeyFormat>> result = new HashMap<>(); |
| result.put( |
| "HMAC_SHA256_PRF", |
| new KeyFactory.KeyFormat<>( |
| HmacPrfKeyFormat.newBuilder() |
| .setParams(HmacPrfParams.newBuilder().setHash(HashType.SHA256).build()) |
| .setKeySize(32) |
| .build(), |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "HMAC_SHA512_PRF", |
| new KeyFactory.KeyFormat<>( |
| HmacPrfKeyFormat.newBuilder() |
| .setParams(HmacPrfParams.newBuilder().setHash(HashType.SHA512).build()) |
| .setKeySize(64) |
| .build(), |
| KeyTemplate.OutputPrefixType.RAW)); |
| return Collections.unmodifiableMap(result); |
| } |
| }; |
| } |
| |
| public static void register(boolean newKeyAllowed) throws GeneralSecurityException { |
| Registry.registerKeyManager(new HmacPrfKeyManager(), newKeyAllowed); |
| } |
| |
| /** |
| * Returns a {@link KeyTemplate} that generates new instances of HMAC keys with the following |
| * parameters: |
| * |
| * <ul> |
| * <li>Key size: 32 bytes |
| * <li>Hash function: SHA256 |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("HMAC_SHA256_PRF")} |
| */ |
| @Deprecated |
| public static final KeyTemplate hmacSha256Template() { |
| return createTemplate(32, HashType.SHA256); |
| } |
| |
| /** |
| * Returns a {@link KeyTemplate} that generates new instances of HMAC keys with the following |
| * parameters: |
| * |
| * <ul> |
| * <li>Key size: 64 bytes |
| * <li>Hash function: SHA512 |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("HMAC_SHA512_PRF")} |
| */ |
| @Deprecated |
| public static final KeyTemplate hmacSha512Template() { |
| return createTemplate(64, HashType.SHA512); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} containing a {@link HmacKeyFormat} with some specified |
| * parameters. |
| */ |
| private static KeyTemplate createTemplate(int keySize, HashType hashType) { |
| HmacPrfParams params = HmacPrfParams.newBuilder().setHash(hashType).build(); |
| HmacPrfKeyFormat format = |
| HmacPrfKeyFormat.newBuilder().setParams(params).setKeySize(keySize).build(); |
| return KeyTemplate.create( |
| new HmacPrfKeyManager().getKeyType(), |
| format.toByteArray(), |
| KeyTemplate.OutputPrefixType.RAW); |
| } |
| } |