| // 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.hybrid; |
| |
| import com.google.crypto.tink.HybridDecrypt; |
| import com.google.crypto.tink.KeyTemplate; |
| import com.google.crypto.tink.KeyTemplates; |
| import com.google.crypto.tink.KeyTypeManager; |
| import com.google.crypto.tink.PrivateKeyTypeManager; |
| import com.google.crypto.tink.Registry; |
| import com.google.crypto.tink.aead.AesCtrHmacAeadKeyManager; |
| import com.google.crypto.tink.aead.AesGcmKeyManager; |
| import com.google.crypto.tink.proto.EcPointFormat; |
| import com.google.crypto.tink.proto.EciesAeadDemParams; |
| import com.google.crypto.tink.proto.EciesAeadHkdfKeyFormat; |
| import com.google.crypto.tink.proto.EciesAeadHkdfParams; |
| import com.google.crypto.tink.proto.EciesAeadHkdfPrivateKey; |
| import com.google.crypto.tink.proto.EciesAeadHkdfPublicKey; |
| import com.google.crypto.tink.proto.EciesHkdfKemParams; |
| import com.google.crypto.tink.proto.EllipticCurveType; |
| import com.google.crypto.tink.proto.HashType; |
| import com.google.crypto.tink.proto.KeyData.KeyMaterialType; |
| import com.google.crypto.tink.proto.OutputPrefixType; |
| import com.google.crypto.tink.subtle.EciesAeadHkdfDemHelper; |
| import com.google.crypto.tink.subtle.EciesAeadHkdfHybridDecrypt; |
| import com.google.crypto.tink.subtle.EllipticCurves; |
| 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.security.KeyPair; |
| import java.security.interfaces.ECPrivateKey; |
| import java.security.interfaces.ECPublicKey; |
| import java.security.spec.ECPoint; |
| import java.util.Collections; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * This key manager generates new {@code EciesAeadHkdfPrivateKey} keys and produces new instances of |
| * {@code EciesAeadHkdfHybridDecrypt}. |
| */ |
| public final class EciesAeadHkdfPrivateKeyManager |
| extends PrivateKeyTypeManager<EciesAeadHkdfPrivateKey, EciesAeadHkdfPublicKey> { |
| EciesAeadHkdfPrivateKeyManager() { |
| super( |
| EciesAeadHkdfPrivateKey.class, |
| EciesAeadHkdfPublicKey.class, |
| new KeyTypeManager.PrimitiveFactory<HybridDecrypt, EciesAeadHkdfPrivateKey>( |
| HybridDecrypt.class) { |
| @Override |
| public HybridDecrypt getPrimitive(EciesAeadHkdfPrivateKey recipientKeyProto) |
| throws GeneralSecurityException { |
| EciesAeadHkdfParams eciesParams = recipientKeyProto.getPublicKey().getParams(); |
| EciesHkdfKemParams kemParams = eciesParams.getKemParams(); |
| |
| ECPrivateKey recipientPrivateKey = |
| EllipticCurves.getEcPrivateKey( |
| HybridUtil.toCurveType(kemParams.getCurveType()), |
| recipientKeyProto.getKeyValue().toByteArray()); |
| EciesAeadHkdfDemHelper demHelper = |
| new RegistryEciesAeadHkdfDemHelper(eciesParams.getDemParams().getAeadDem()); |
| return new EciesAeadHkdfHybridDecrypt( |
| recipientPrivateKey, |
| kemParams.getHkdfSalt().toByteArray(), |
| HybridUtil.toHmacAlgo(kemParams.getHkdfHashType()), |
| HybridUtil.toPointFormatType(eciesParams.getEcPointFormat()), |
| demHelper); |
| } |
| }); |
| } |
| |
| @Override |
| public String getKeyType() { |
| return "type.googleapis.com/google.crypto.tink.EciesAeadHkdfPrivateKey"; |
| } |
| |
| @Override |
| public int getVersion() { |
| return 0; |
| } |
| |
| @Override |
| public EciesAeadHkdfPublicKey getPublicKey(EciesAeadHkdfPrivateKey key) |
| throws GeneralSecurityException { |
| return key.getPublicKey(); |
| } |
| |
| @Override |
| public KeyMaterialType keyMaterialType() { |
| return KeyMaterialType.ASYMMETRIC_PRIVATE; |
| } |
| |
| @Override |
| public EciesAeadHkdfPrivateKey parseKey(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return EciesAeadHkdfPrivateKey.parseFrom(byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public void validateKey(EciesAeadHkdfPrivateKey keyProto) throws GeneralSecurityException { |
| if (keyProto.getKeyValue().isEmpty()) { |
| throw new GeneralSecurityException("invalid ECIES private key"); |
| } |
| Validators.validateVersion(keyProto.getVersion(), getVersion()); |
| HybridUtil.validate(keyProto.getPublicKey().getParams()); |
| } |
| |
| @Override |
| public KeyFactory<EciesAeadHkdfKeyFormat, EciesAeadHkdfPrivateKey> keyFactory() { |
| return new KeyFactory<EciesAeadHkdfKeyFormat, EciesAeadHkdfPrivateKey>( |
| EciesAeadHkdfKeyFormat.class) { |
| @Override |
| public void validateKeyFormat(EciesAeadHkdfKeyFormat eciesKeyFormat) |
| throws GeneralSecurityException { |
| HybridUtil.validate(eciesKeyFormat.getParams()); |
| } |
| |
| @Override |
| public EciesAeadHkdfKeyFormat parseKeyFormat(ByteString byteString) |
| throws InvalidProtocolBufferException { |
| return EciesAeadHkdfKeyFormat.parseFrom( |
| byteString, ExtensionRegistryLite.getEmptyRegistry()); |
| } |
| |
| @Override |
| public EciesAeadHkdfPrivateKey createKey(EciesAeadHkdfKeyFormat eciesKeyFormat) |
| throws GeneralSecurityException { |
| EciesHkdfKemParams kemParams = eciesKeyFormat.getParams().getKemParams(); |
| KeyPair keyPair = |
| EllipticCurves.generateKeyPair(HybridUtil.toCurveType(kemParams.getCurveType())); |
| ECPublicKey pubKey = (ECPublicKey) keyPair.getPublic(); |
| ECPrivateKey privKey = (ECPrivateKey) keyPair.getPrivate(); |
| ECPoint w = pubKey.getW(); |
| |
| // Creates EciesAeadHkdfPublicKey. |
| EciesAeadHkdfPublicKey eciesPublicKey = |
| EciesAeadHkdfPublicKey.newBuilder() |
| .setVersion(getVersion()) |
| .setParams(eciesKeyFormat.getParams()) |
| .setX(ByteString.copyFrom(w.getAffineX().toByteArray())) |
| .setY(ByteString.copyFrom(w.getAffineY().toByteArray())) |
| .build(); |
| |
| // Creates EciesAeadHkdfPrivateKey. |
| return EciesAeadHkdfPrivateKey.newBuilder() |
| .setVersion(getVersion()) |
| .setPublicKey(eciesPublicKey) |
| .setKeyValue(ByteString.copyFrom(privKey.getS().toByteArray())) |
| .build(); |
| } |
| |
| @Override |
| public Map<String, KeyFactory.KeyFormat<EciesAeadHkdfKeyFormat>> keyFormats() |
| throws GeneralSecurityException { |
| Map<String, KeyFactory.KeyFormat<EciesAeadHkdfKeyFormat>> result = new HashMap<>(); |
| result.put( |
| "ECIES_P256_HKDF_HMAC_SHA256_AES128_GCM", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.UNCOMPRESSED, |
| KeyTemplates.get("AES128_GCM"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.TINK)); |
| result.put( |
| "ECIES_P256_HKDF_HMAC_SHA256_AES128_GCM_RAW", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.UNCOMPRESSED, |
| KeyTemplates.get("AES128_GCM"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_GCM", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| KeyTemplates.get("AES128_GCM"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.TINK)); |
| result.put( |
| "ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_GCM_RAW", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| KeyTemplates.get("AES128_GCM"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.RAW)); |
| // backward compatibility with HybridKeyTemplates |
| result.put( |
| "ECIES_P256_HKDF_HMAC_SHA256_AES128_GCM_COMPRESSED_WITHOUT_PREFIX", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| KeyTemplates.get("AES128_GCM"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "ECIES_P256_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.UNCOMPRESSED, |
| KeyTemplates.get("AES128_CTR_HMAC_SHA256"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.TINK)); |
| result.put( |
| "ECIES_P256_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256_RAW", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.UNCOMPRESSED, |
| KeyTemplates.get("AES128_CTR_HMAC_SHA256"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.RAW)); |
| result.put( |
| "ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| KeyTemplates.get("AES128_CTR_HMAC_SHA256"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.TINK)); |
| result.put( |
| "ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256_RAW", |
| createKeyFormat( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| KeyTemplates.get("AES128_CTR_HMAC_SHA256"), |
| EMPTY_SALT, |
| KeyTemplate.OutputPrefixType.RAW)); |
| return Collections.unmodifiableMap(result); |
| } |
| }; |
| } |
| |
| /** |
| * Registers the {@link EciesAeadHkdfPrivateKeyManager} and the {@link |
| * EciesAeadHkdfPublicKeyManager} with the registry, so that the the EciesAeadHkdfKeys can be used |
| * with Tink. |
| */ |
| public static void registerPair(boolean newKeyAllowed) throws GeneralSecurityException { |
| Registry.registerAsymmetricKeyManagers( |
| new EciesAeadHkdfPrivateKeyManager(), new EciesAeadHkdfPublicKeyManager(), newKeyAllowed); |
| } |
| |
| private static final byte[] EMPTY_SALT = new byte[0]; |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of ECIES-AEAD-HKDF key pairs with |
| * the following parameters: |
| * <ul> |
| * <li>KEM: ECDH over NIST P-256 |
| * <li>DEM: AES128-GCM |
| * <li>KDF: HKDF-HMAC-SHA256 with an empty salt |
| * <li>EC Point Format: Uncompressed |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#TINK} |
| * </ul> |
| * <p>Unlike other key templates that use AES-GCM, the instances of {@link HybridDecrypt} |
| * generated by this key template has no limitation on Android KitKat (API level 19). They |
| * might not work in older versions though. |
| * @deprecated use {@code KeyTemplates.get("ECIES_P256_HKDF_HMAC_SHA256_AES128_GCM")} |
| */ |
| @Deprecated |
| public static final KeyTemplate eciesP256HkdfHmacSha256Aes128GcmTemplate() { |
| return createKeyTemplate( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.UNCOMPRESSED, |
| AesGcmKeyManager.aes128GcmTemplate(), |
| KeyTemplate.OutputPrefixType.TINK, |
| EMPTY_SALT); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of ECIES-AEAD-HKDF key pairs with |
| * the following parameters: |
| * <ul> |
| * <li>KEM: ECDH over NIST P-256 |
| * <li>DEM: AES128-GCM |
| * <li>KDF: HKDF-HMAC-SHA256 with an empty salt |
| * <li>EC Point Format: Compressed |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} (no prefix) |
| * </ul> |
| * <p>Unlike other key templates that use AES-GCM, the instances of {@link HybridDecrypt} |
| * generated by this key template has no limitation on Android KitKat (API level 19). They |
| * might not work in older versions though. |
| * @deprecated use {@code |
| * KeyTemplates.get("ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_GCM_RAW")} |
| */ |
| @Deprecated |
| public static final KeyTemplate rawEciesP256HkdfHmacSha256Aes128GcmCompressedTemplate() { |
| return createKeyTemplate( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| AesGcmKeyManager.aes128GcmTemplate(), |
| KeyTemplate.OutputPrefixType.RAW, |
| EMPTY_SALT); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of ECIES-AEAD-HKDF key pairs with |
| * the following parameters: |
| * <ul> |
| * <li>KEM: ECDH over NIST P-256 |
| * <li>DEM: AES128-CTR-HMAC-SHA256 with the following parameters |
| * <ul> |
| * <li>AES key size: 16 bytes |
| * <li>AES CTR IV size: 16 bytes |
| * <li>HMAC key size: 32 bytes |
| * <li>HMAC tag size: 16 bytes |
| * </ul> |
| * <li>KDF: HKDF-HMAC-SHA256 with an empty salt |
| * <li>EC Point Format: Uncompressed |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#TINK} |
| * </ul> |
| * |
| * @deprecated use {@code KeyTemplates.get("ECIES_P256_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256")} |
| */ |
| @Deprecated |
| public static final KeyTemplate eciesP256HkdfHmacSha256Aes128CtrHmacSha256Template() { |
| return createKeyTemplate( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.UNCOMPRESSED, |
| AesCtrHmacAeadKeyManager.aes128CtrHmacSha256Template(), |
| KeyTemplate.OutputPrefixType.TINK, |
| EMPTY_SALT); |
| } |
| |
| /** |
| * @return a {@link KeyTemplate} that generates new instances of ECIES-AEAD-HKDF key pairs with |
| * the following parameters: |
| * <ul> |
| * <li>KEM: ECDH over NIST P-256 |
| * <li>DEM: AES128-CTR-HMAC-SHA256 with the following parameters |
| * <ul> |
| * <li>AES key size: 16 bytes |
| * <li>AES CTR IV size: 16 bytes |
| * <li>HMAC key size: 32 bytes |
| * <li>HMAC tag size: 16 bytes |
| * </ul> |
| * <li>KDF: HKDF-HMAC-SHA256 with an empty salt |
| * <li>EC Point Format: Compressed |
| * <li>Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} (no prefix) |
| * </ul> |
| * |
| * @deprecated use {@code |
| * KeyTemplates.get("ECIES_P256_COMPRESSED_HKDF_HMAC_SHA256_AES128_CTR_HMAC_SHA256_RAW")} |
| */ |
| @Deprecated |
| public static final KeyTemplate |
| rawEciesP256HkdfHmacSha256Aes128CtrHmacSha256CompressedTemplate() { |
| return createKeyTemplate( |
| EllipticCurveType.NIST_P256, |
| HashType.SHA256, |
| EcPointFormat.COMPRESSED, |
| AesCtrHmacAeadKeyManager.aes128CtrHmacSha256Template(), |
| KeyTemplate.OutputPrefixType.RAW, |
| EMPTY_SALT); |
| } |
| |
| /** @return a {@link KeyTemplate} containing a {@link EciesAeadHkdfKeyFormat}. */ |
| private static KeyTemplate createKeyTemplate( |
| EllipticCurveType curve, |
| HashType hashType, |
| EcPointFormat ecPointFormat, |
| KeyTemplate demKeyTemplate, |
| KeyTemplate.OutputPrefixType outputPrefixType, |
| byte[] salt) { |
| EciesAeadHkdfKeyFormat format = |
| EciesAeadHkdfKeyFormat.newBuilder() |
| .setParams(createParams(curve, hashType, ecPointFormat, demKeyTemplate, salt)) |
| .build(); |
| return KeyTemplate.create( |
| new EciesAeadHkdfPrivateKeyManager().getKeyType(), format.toByteArray(), outputPrefixType); |
| } |
| |
| private static KeyFactory.KeyFormat<EciesAeadHkdfKeyFormat> createKeyFormat( |
| EllipticCurveType curve, |
| HashType hashType, |
| EcPointFormat ecPointFormat, |
| KeyTemplate demKeyTemplate, |
| byte[] salt, |
| KeyTemplate.OutputPrefixType prefixType) { |
| return new KeyFactory.KeyFormat<>( |
| EciesAeadHkdfKeyFormat.newBuilder() |
| .setParams(createParams(curve, hashType, ecPointFormat, demKeyTemplate, salt)) |
| .build(), |
| prefixType); |
| } |
| |
| /** @return a {@link EciesAeadHkdfParams} with the specified parameters. */ |
| static EciesAeadHkdfParams createParams( |
| EllipticCurveType curve, |
| HashType hashType, |
| EcPointFormat ecPointFormat, |
| KeyTemplate demKeyTemplate, |
| byte[] salt) { |
| EciesHkdfKemParams kemParams = |
| EciesHkdfKemParams.newBuilder() |
| .setCurveType(curve) |
| .setHkdfHashType(hashType) |
| .setHkdfSalt(ByteString.copyFrom(salt)) |
| .build(); |
| com.google.crypto.tink.proto.KeyTemplate protoKt = |
| com.google.crypto.tink.proto.KeyTemplate.newBuilder() |
| .setTypeUrl(demKeyTemplate.getTypeUrl()) |
| .setValue(ByteString.copyFrom(demKeyTemplate.getValue())) |
| .setOutputPrefixType(toProto(demKeyTemplate.getOutputPrefixType())) |
| .build(); |
| EciesAeadDemParams demParams = EciesAeadDemParams.newBuilder().setAeadDem(protoKt).build(); |
| return EciesAeadHkdfParams.newBuilder() |
| .setKemParams(kemParams) |
| .setDemParams(demParams) |
| .setEcPointFormat(ecPointFormat) |
| .build(); |
| } |
| |
| private static OutputPrefixType toProto(KeyTemplate.OutputPrefixType outputPrefixType) { |
| switch (outputPrefixType) { |
| case TINK: |
| return OutputPrefixType.TINK; |
| case LEGACY: |
| return OutputPrefixType.LEGACY; |
| case RAW: |
| return OutputPrefixType.RAW; |
| case CRUNCHY: |
| return OutputPrefixType.CRUNCHY; |
| } |
| throw new IllegalArgumentException("Unknown output prefix type"); |
| } |
| } |
