cl.whyem.testsutilityproject.otpgenerator.KeyBase.java Source code

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Here is the source code for cl.whyem.testsutilityproject.otpgenerator.KeyBase.java

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/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  The ASF licenses this file to You
 * 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.  For additional information regarding
 * copyright in this work, please see the NOTICE file in the top level
 * directory of this distribution.
 */
package cl.whyem.testsutilityproject.otpgenerator;

import com.google.common.base.Objects;
import java.security.Key;
import java.security.SecureRandom;

import javax.crypto.Mac;
import javax.crypto.spec.SecretKeySpec;

import org.apache.commons.codec.binary.Hex;

import com.google.common.base.Supplier;

public abstract class KeyBase implements Supplier<String> {

    public static final String DEFAULT_ALG = "HmacSHA256";
    public static final int DEFAULT_SIZE = 256;

    protected final Key key;
    protected final String alg;
    protected final int size;

    public abstract String generateNext();

    public String get() {
        return generateNext();
    }

    public KeyBase(Key key) {
        this(key, DEFAULT_ALG, DEFAULT_SIZE);
    }

    public KeyBase(Key key, int size) {
        this(key, DEFAULT_ALG, size);
    }

    public KeyBase(Key key, String alg, int size) {
        this.key = key;
        this.alg = alg;
        this.size = size;
    }

    public KeyBase(String key) {
        this(key, DEFAULT_ALG, DEFAULT_SIZE);
    }

    public KeyBase(String key, int size) {
        this(key, DEFAULT_ALG, size);
    }

    public KeyBase(byte[] key, String alg, int size) {
        this.key = secret(key);
        this.alg = alg;
        this.size = size;
    }

    public KeyBase(byte[] key, int size) {
        this(key, DEFAULT_ALG, size);
    }

    public KeyBase(String key, String alg, int size) {
        this(dec(key), alg, size);
    }

    protected SecretKeySpec secret(byte[] key) {
        return new SecretKeySpec(key, "RAW");
    }

    protected static byte[] dec(String val) {
        try {
            return Hex.decodeHex(val.toCharArray());
        } catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }

    protected byte[] hmac(byte[]... mat) {
        try {
            Mac hmac = Mac.getInstance(alg);
            hmac.init(key);
            for (byte[] m : mat) {
                hmac.update(m);
            }
            return hmac.doFinal();
        } catch (Throwable t) {
            throw new RuntimeException(t);
        }
    }

    protected byte[] randomBytes(int count) {
        SecureRandom random = new SecureRandom();
        byte[] buf = new byte[count];
        random.nextBytes(buf);
        return buf;
    }

    protected String pad(String s, int len, char c) {
        while (s.length() < len) {
            s = c + s;
        }
        return s;
    }

    @Override
    public int hashCode() {
        return Objects.hashCode(1, alg, key);
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) {
            return true;
        }
        if (obj == null) {
            return false;
        }
        if (getClass() != obj.getClass()) {
            return false;
        }
        KeyBase other = (KeyBase) obj;
        if (alg == null) {
            if (other.alg != null) {
                return false;
            }
        } else if (!alg.equals(other.alg)) {
            return false;
        }
        if (key == null) {
            if (other.key != null) {
                return false;
            }
        } else if (!key.equals(other.key)) {
            return false;
        }
        if (size != other.size) {
            return false;
        }
        return true;
    }

}