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      1 /*
      2  * Copyright (C) 2017 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 package org.conscrypt;
     18 
     19 import java.io.IOException;
     20 import java.security.AlgorithmParametersSpi;
     21 import java.security.InvalidAlgorithmParameterException;
     22 import java.security.spec.AlgorithmParameterSpec;
     23 import java.security.spec.ECGenParameterSpec;
     24 import java.security.spec.ECParameterSpec;
     25 import java.security.spec.InvalidParameterSpecException;
     26 
     27 /**
     28  * AlgorithmParameters implementation for elliptic curves.  The only supported encoding format is
     29  * ASN.1, as specified in RFC 3279, section 2.3.5.  However, only named curves are supported.
     30  *
     31  * @hide
     32  */
     33 @Internal
     34 public class ECParameters extends AlgorithmParametersSpi {
     35 
     36     private OpenSSLECGroupContext curve;
     37 
     38     @Override
     39     protected void engineInit(AlgorithmParameterSpec algorithmParameterSpec)
     40             throws InvalidParameterSpecException {
     41         if (algorithmParameterSpec instanceof ECGenParameterSpec) {
     42             String newCurveName = ((ECGenParameterSpec) algorithmParameterSpec).getName();
     43             OpenSSLECGroupContext newCurve = OpenSSLECGroupContext.getCurveByName(newCurveName);
     44             if (newCurve == null) {
     45                 throw new InvalidParameterSpecException("Unknown EC curve name: " + newCurveName);
     46             }
     47             this.curve = newCurve;
     48         } else if (algorithmParameterSpec instanceof ECParameterSpec) {
     49             ECParameterSpec ecParamSpec = (ECParameterSpec) algorithmParameterSpec;
     50             try {
     51                 OpenSSLECGroupContext newCurve = OpenSSLECGroupContext.getInstance(ecParamSpec);
     52                 if (newCurve == null) {
     53                     throw new InvalidParameterSpecException("Unknown EC curve: " + ecParamSpec);
     54                 }
     55                 this.curve = newCurve;
     56             } catch (InvalidAlgorithmParameterException e) {
     57                 throw new InvalidParameterSpecException(e.getMessage());
     58             }
     59         } else {
     60             throw new InvalidParameterSpecException(
     61                     "Only ECParameterSpec and ECGenParameterSpec are supported");
     62         }
     63     }
     64 
     65     @Override
     66     protected void engineInit(byte[] bytes) throws IOException {
     67         long ref = NativeCrypto.EC_KEY_parse_curve_name(bytes);
     68         if (ref == 0) {
     69             throw new IOException("Error reading ASN.1 encoding");
     70         }
     71         this.curve = new OpenSSLECGroupContext(new NativeRef.EC_GROUP(ref));
     72     }
     73 
     74     @Override
     75     protected void engineInit(byte[] bytes, String format) throws IOException {
     76         if (format == null || format.equals("ASN.1")) {
     77             engineInit(bytes);
     78         } else {
     79             throw new IOException("Unsupported format: " + format);
     80         }
     81     }
     82 
     83     @Override
     84     @SuppressWarnings("unchecked")
     85     protected <T extends AlgorithmParameterSpec> T engineGetParameterSpec(Class<T> aClass)
     86             throws InvalidParameterSpecException {
     87         if (aClass == ECParameterSpec.class) {
     88             return (T) curve.getECParameterSpec();
     89         } else if (aClass == ECGenParameterSpec.class) {
     90             return (T) new ECGenParameterSpec(Platform.getCurveName(curve.getECParameterSpec()));
     91         } else {
     92             throw new InvalidParameterSpecException("Unsupported class: " + aClass);
     93         }
     94     }
     95 
     96     @Override
     97     protected byte[] engineGetEncoded() throws IOException {
     98         return NativeCrypto.EC_KEY_marshal_curve_name(curve.getNativeRef());
     99     }
    100 
    101     @Override
    102     protected byte[] engineGetEncoded(String format) throws IOException {
    103         if (format == null || format.equals("ASN.1")) {
    104             return engineGetEncoded();
    105         }
    106         throw new IOException("Unsupported format: " + format);
    107     }
    108 
    109     @Override
    110     protected String engineToString() {
    111         return "Conscrypt EC AlgorithmParameters";
    112     }
    113 }
    114