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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

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 * This code is free software; you can redistribute it and/or modify it

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 * published by the Free Software Foundation.  Oracle designates this

 * particular file as subject to the "Classpath" exception as provided

 * by Oracle in the LICENSE file that accompanied this code.

 *

 * This code is distributed in the hope that it will be useful, but WITHOUT

 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * version 2 for more details (a copy is included in the LICENSE file that

 * accompanied this code).

 *

 * You should have received a copy of the GNU General Public License version

 * 2 along with this work; if not, write to the Free Software Foundation,

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 *

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package com.sun.crypto.provider;

import java.util.Arrays;

import java.nio.ByteBuffer;

import javax.crypto.MacSpi;

import javax.crypto.SecretKey;

import javax.crypto.spec.SecretKeySpec;

import javax.crypto.spec.PBEKeySpec;

import javax.crypto.spec.PBEParameterSpec;

import java.security.*;

import java.security.spec.*;

/**

 * This is an implementation of the PBMAC1 algorithms as defined

 * in PKCS#5 v2.1 standard.

 */

abstract class PBMAC1Core extends HmacCore {

    // NOTE: this class inherits the Cloneable interface from HmacCore

    // Need to override clone() if mutable fields are added.

    private final String kdfAlgo;

    private final String hashAlgo;

    private final int blockLength; // in octets

    /**

     * Creates an instance of PBMAC1 according to the selected

     * password-based key derivation function.

     */

    PBMAC1Core(String kdfAlgo, String hashAlgo, int blockLength)

        throws NoSuchAlgorithmException {

        super(hashAlgo, blockLength);

        this.kdfAlgo = kdfAlgo;

        this.hashAlgo = hashAlgo;

        this.blockLength = blockLength;

    }

    private static PBKDF2Core getKDFImpl(String algo) {

        PBKDF2Core kdf = null;

        switch(algo) {

        case "HmacSHA1":

                kdf = new PBKDF2Core.HmacSHA1();

                break;

        case "HmacSHA224":

                kdf = new PBKDF2Core.HmacSHA224();

                break;

        case "HmacSHA256":

                kdf = new PBKDF2Core.HmacSHA256();

                break;

        case "HmacSHA384":

                kdf = new PBKDF2Core.HmacSHA384();

                break;

        case "HmacSHA512":

                kdf = new PBKDF2Core.HmacSHA512();

                break;

        default:

                throw new ProviderException(

                    "No MAC implementation for " + algo);

        }

        return kdf;

    }

    /**

     * Initializes the HMAC with the given secret key and algorithm parameters.

     *

     * @param key the secret key.

     * @param params the algorithm parameters.

     *

     * @exception InvalidKeyException if the given key is inappropriate for

     * initializing this MAC.

     * @exception InvalidAlgorithmParameterException if the given algorithm

     * parameters are inappropriate for this MAC.

     */

    protected void engineInit(Key key, AlgorithmParameterSpec params)

        throws InvalidKeyException, InvalidAlgorithmParameterException {

        char[] passwdChars;

        byte[] salt = null;

        int iCount = 0;

        if (key instanceof javax.crypto.interfaces.PBEKey) {

            javax.crypto.interfaces.PBEKey pbeKey =

                (javax.crypto.interfaces.PBEKey) key;

            passwdChars = pbeKey.getPassword();

            salt = pbeKey.getSalt(); // maybe null if unspecified

            iCount = pbeKey.getIterationCount(); // maybe 0 if unspecified

        } else if (key instanceof SecretKey) {

            byte[] passwdBytes = key.getEncoded();

            if ((passwdBytes == null) ||

                !(key.getAlgorithm().regionMatches(true, 0, "PBE", 0, 3))) {

                throw new InvalidKeyException("Missing password");

            }

            passwdChars = new char[passwdBytes.length];

            for (int i=0; i<passwdChars.length; i++) {

                passwdChars[i] = (char) (passwdBytes[i] & 0x7f);

            }

        } else {

            throw new InvalidKeyException("SecretKey of PBE type required");

        }

        if (params == null) {

            // should not auto-generate default values since current

            // javax.crypto.Mac api does not have any method for caller to

            // retrieve the generated defaults.

            if ((salt == null) || (iCount == 0)) {

                throw new InvalidAlgorithmParameterException

                    ("PBEParameterSpec required for salt and iteration count");

            }

        } else if (!(params instanceof PBEParameterSpec)) {

            throw new InvalidAlgorithmParameterException

                ("PBEParameterSpec type required");

        } else {

            PBEParameterSpec pbeParams = (PBEParameterSpec) params;

            // make sure the parameter values are consistent

            if (salt != null) {

                if (!Arrays.equals(salt, pbeParams.getSalt())) {

                    throw new InvalidAlgorithmParameterException

                        ("Inconsistent value of salt between key and params");

                }

            } else {

                salt = pbeParams.getSalt();

            }

            if (iCount != 0) {

                if (iCount != pbeParams.getIterationCount()) {

                    throw new InvalidAlgorithmParameterException

                        ("Different iteration count between key and params");

                }

            } else {

                iCount = pbeParams.getIterationCount();

            }

        }

        // For security purpose, we need to enforce a minimum length

        // for salt; just require the minimum salt length to be 8-byte

        // which is what PKCS#5 recommends and openssl does.

        if (salt.length < 8) {

            throw new InvalidAlgorithmParameterException

                ("Salt must be at least 8 bytes long");

        }

        if (iCount <= 0) {

            throw new InvalidAlgorithmParameterException

                ("IterationCount must be a positive number");

        }

        PBEKeySpec pbeSpec =

            new PBEKeySpec(passwdChars, salt, iCount, blockLength);

            // password char[] was cloned in PBEKeySpec constructor,

            // so we can zero it out here

        java.util.Arrays.fill(passwdChars, ' ');

        SecretKey s = null;

        PBKDF2Core kdf = getKDFImpl(kdfAlgo);

        try {

            s = kdf.engineGenerateSecret(pbeSpec);

        } catch (InvalidKeySpecException ikse) {

            InvalidKeyException ike =

                new InvalidKeyException("Cannot construct PBE key");

            ike.initCause(ikse);

            throw ike;

        }

        byte[] derivedKey = s.getEncoded();

        SecretKey cipherKey = new SecretKeySpec(derivedKey, kdfAlgo);

        super.engineInit(cipherKey, null);

    }

    public static final class HmacSHA1 extends PBMAC1Core {

        public HmacSHA1() throws NoSuchAlgorithmException {

            super("HmacSHA1", "SHA1", 64);

        }

    }

    public static final class HmacSHA224 extends PBMAC1Core {

        public HmacSHA224() throws NoSuchAlgorithmException {

            super("HmacSHA224", "SHA-224", 64);

        }

    }

    public static final class HmacSHA256 extends PBMAC1Core {

        public HmacSHA256() throws NoSuchAlgorithmException {

            super("HmacSHA256", "SHA-256", 64);

        }

    }

    public static final class HmacSHA384 extends PBMAC1Core {

        public HmacSHA384() throws NoSuchAlgorithmException {

            super("HmacSHA384", "SHA-384", 128);

        }

    }

    public static final class HmacSHA512 extends PBMAC1Core {

        public HmacSHA512() throws NoSuchAlgorithmException {

            super("HmacSHA512", "SHA-512", 128);

        }

    }

}