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Tink is a small cryptographic library that provides a safe, simple, agile and fast way to accomplish some common cryptographic tasks.
// 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 {
EciesAeadHkdfPrivateKeyManager() {
super(
EciesAeadHkdfPrivateKey.class,
EciesAeadHkdfPublicKey.class,
new KeyTypeManager.PrimitiveFactory(
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 keyFactory() {
return new KeyFactory(
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> keyFormats()
throws GeneralSecurityException {
Map> 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:
*
* - KEM: ECDH over NIST P-256
*
- DEM: AES128-GCM
*
- KDF: HKDF-HMAC-SHA256 with an empty salt
*
- EC Point Format: Uncompressed
*
- Prefix type: {@link KeyTemplate.OutputPrefixType#TINK}
*
* 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:
*
* - KEM: ECDH over NIST P-256
*
- DEM: AES128-GCM
*
- KDF: HKDF-HMAC-SHA256 with an empty salt
*
- EC Point Format: Compressed
*
- Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} (no prefix)
*
* 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:
*
* - KEM: ECDH over NIST P-256
*
- DEM: AES128-CTR-HMAC-SHA256 with the following parameters
*
* - AES key size: 16 bytes
*
- AES CTR IV size: 16 bytes
*
- HMAC key size: 32 bytes
*
- HMAC tag size: 16 bytes
*
* - KDF: HKDF-HMAC-SHA256 with an empty salt
*
- EC Point Format: Uncompressed
*
- Prefix type: {@link KeyTemplate.OutputPrefixType#TINK}
*
*
* @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:
*
* - KEM: ECDH over NIST P-256
*
- DEM: AES128-CTR-HMAC-SHA256 with the following parameters
*
* - AES key size: 16 bytes
*
- AES CTR IV size: 16 bytes
*
- HMAC key size: 32 bytes
*
- HMAC tag size: 16 bytes
*
* - KDF: HKDF-HMAC-SHA256 with an empty salt
*
- EC Point Format: Compressed
*
- Prefix type: {@link KeyTemplate.OutputPrefixType#RAW} (no prefix)
*
*
* @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 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");
}
}
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