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

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 * 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

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 * accompanied this code).

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package com.sun.crypto.provider;

import java.security.*;

import java.security.spec.*;

import javax.crypto.*;

import javax.crypto.spec.*;

/**

 * This class represents password-based encryption as defined by the PKCS #5

 * standard.

 *

 * @author Jan Luehe

 *

 *

 * @see javax.crypto.Cipher

 */

final class PBES1Core {

    // the encapsulated DES cipher

    private CipherCore cipher;

    private MessageDigest md;

    private int blkSize;

    private String algo = null;

    private byte[] salt = null;

    private int iCount = 10;

    /**

     * Creates an instance of PBE Cipher using the specified CipherSpi

     * instance.

     *

     */

    PBES1Core(String cipherAlg) throws NoSuchAlgorithmException,

        NoSuchPaddingException {

        algo = cipherAlg;

        if (algo.equals("DES")) {

            cipher = new CipherCore(new DESCrypt(),

                                    DESConstants.DES_BLOCK_SIZE);

        } else if (algo.equals("DESede")) {

            cipher = new CipherCore(new DESedeCrypt(),

                                    DESConstants.DES_BLOCK_SIZE);

        } else {

            throw new NoSuchAlgorithmException("No Cipher implementation " +

                                               "for PBEWithMD5And" + algo);

        }

        cipher.setMode("CBC");

        cipher.setPadding("PKCS5Padding");

        // get instance of MD5

        md = MessageDigest.getInstance("MD5");

    }

    /**

     * Sets the mode of this cipher. This algorithm can only be run in CBC

     * mode.

     *

     * @param mode the cipher mode

     *

     * @exception NoSuchAlgorithmException if the requested cipher mode is

     * invalid

     */

    void setMode(String mode) throws NoSuchAlgorithmException {

        cipher.setMode(mode);

    }

     /**

     * Sets the padding mechanism of this cipher. This algorithm only uses

     * PKCS #5 padding.

     *

     * @param padding the padding mechanism

     *

     * @exception NoSuchPaddingException if the requested padding mechanism

     * is invalid

     */

    void setPadding(String paddingScheme) throws NoSuchPaddingException {

        cipher.setPadding(paddingScheme);

    }

    /**

     * Returns the block size (in bytes).

     *

     * @return the block size (in bytes)

     */

    int getBlockSize() {

        return DESConstants.DES_BLOCK_SIZE;

    }

    /**

     * Returns the length in bytes that an output buffer would need to be in

     * order to hold the result of the next <code>update</code> or

     * <code>doFinal</code> operation, given the input length

     * <code>inputLen</code> (in bytes).

     *

     * <p>This call takes into account any unprocessed (buffered) data from a

     * previous <code>update</code> call, and padding.

     *

     * <p>The actual output length of the next <code>update</code> or

     * <code>doFinal</code> call may be smaller than the length returned by

     * this method.

     *

     * @param inputLen the input length (in bytes)

     *

     * @return the required output buffer size (in bytes)

     *

     */

    int getOutputSize(int inputLen) {

        return cipher.getOutputSize(inputLen);

    }

    /**

     * Returns the initialization vector (IV) in a new buffer.

     *

     * <p> This is useful in the case where a random IV has been created

     * (see <a href = "#init">init</a>),

     * or in the context of password-based encryption or

     * decryption, where the IV is derived from a user-supplied password.

     *

     * @return the initialization vector in a new buffer, or null if the

     * underlying algorithm does not use an IV, or if the IV has not yet

     * been set.

     */

    byte[] getIV() {

        return cipher.getIV();

    }

    /**

     * Returns the parameters used with this cipher.

     *

     * <p>The returned parameters may be the same that were used to initialize

     * this cipher, or may contain the default set of parameters or a set of

     * randomly generated parameters used by the underlying cipher

     * implementation (provided that the underlying cipher implementation

     * uses a default set of parameters or creates new parameters if it needs

     * parameters but was not initialized with any).

     *

     * @return the parameters used with this cipher, or null if this cipher

     * does not use any parameters.

     */

    AlgorithmParameters getParameters() {

        AlgorithmParameters params = null;

        if (salt == null) {

            salt = new byte[8];

            SunJCE.getRandom().nextBytes(salt);

        }

        PBEParameterSpec pbeSpec = new PBEParameterSpec(salt, iCount);

        try {

            params = AlgorithmParameters.getInstance("PBEWithMD5And" +

                (algo.equalsIgnoreCase("DES")? "DES":"TripleDES"),

                SunJCE.getInstance());

            params.init(pbeSpec);

        } catch (NoSuchAlgorithmException nsae) {

            // should never happen

            throw new RuntimeException("SunJCE called, but not configured");

        } catch (InvalidParameterSpecException ipse) {

            // should never happen

            throw new RuntimeException("PBEParameterSpec not supported");

        }

        return params;

    }

    /**

     * Initializes this cipher with a key, a set of

     * algorithm parameters, and a source of randomness.

     * The cipher is initialized for one of the following four operations:

     * encryption, decryption, key wrapping or key unwrapping, depending on

     * the value of <code>opmode</code>.

     *

     * <p>If this cipher (including its underlying feedback or padding scheme)

     * requires any random bytes, it will get them from <code>random</code>.

     *

     * @param opmode the operation mode of this cipher (this is one of

     * the following:

     * <code>ENCRYPT_MODE</code>, <code>DECRYPT_MODE</code>),

     * <code>WRAP_MODE</code> or <code>UNWRAP_MODE</code>)

     * @param key the encryption key

     * @param params the algorithm parameters

     * @param random the source of randomness

     *

     * @exception InvalidKeyException if the given key is inappropriate for

     * initializing this cipher

     * @exception InvalidAlgorithmParameterException if the given algorithm

     * parameters are inappropriate for this cipher

     */

    void init(int opmode, Key key, AlgorithmParameterSpec params,

              SecureRandom random)

        throws InvalidKeyException, InvalidAlgorithmParameterException {

        if (((opmode == Cipher.DECRYPT_MODE) ||

             (opmode == Cipher.UNWRAP_MODE)) && (params == null)) {

            throw new InvalidAlgorithmParameterException("Parameters "

                                                         + "missing");

        }

        if ((key == null) ||

            (key.getEncoded() == null) ||

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

            throw new InvalidKeyException("Missing password");

        }

        if (params == null) {

            // create random salt and use default iteration count

            salt = new byte[8];

            random.nextBytes(salt);

        } else {

            if (!(params instanceof PBEParameterSpec)) {

                throw new InvalidAlgorithmParameterException

                    ("Wrong parameter type: PBE expected");

            }

            salt = ((PBEParameterSpec) params).getSalt();

            // salt must be 8 bytes long (by definition)

            if (salt.length != 8) {

                throw new InvalidAlgorithmParameterException

                    ("Salt must be 8 bytes long");

            }

            iCount = ((PBEParameterSpec) params).getIterationCount();

            if (iCount <= 0) {

                throw new InvalidAlgorithmParameterException

                    ("IterationCount must be a positive number");

            }

        }

        byte[] derivedKey = deriveCipherKey(key);

        // use all but the last 8 bytes as the key value

        SecretKeySpec cipherKey = new SecretKeySpec(derivedKey, 0,

                                                    derivedKey.length-8, algo);

        // use the last 8 bytes as the IV

        IvParameterSpec ivSpec = new IvParameterSpec(derivedKey,

                                                     derivedKey.length-8,

                                                     8);

        // initialize the underlying cipher

        cipher.init(opmode, cipherKey, ivSpec, random);

    }

    private byte[] deriveCipherKey(Key key) {

        byte[] result = null;

        byte[] passwdBytes = key.getEncoded();

        if (algo.equals("DES")) {

            // P || S (password concatenated with salt)

            byte[] concat = new byte[Math.addExact(passwdBytes.length, salt.length)];

            System.arraycopy(passwdBytes, 0, concat, 0, passwdBytes.length);

            java.util.Arrays.fill(passwdBytes, (byte)0x00);

            System.arraycopy(salt, 0, concat, passwdBytes.length, salt.length);

            // digest P || S with c iterations

            byte[] toBeHashed = concat;

            for (int i = 0; i < iCount; i++) {

                md.update(toBeHashed);

                toBeHashed = md.digest(); // this resets the digest

            }

            java.util.Arrays.fill(concat, (byte)0x00);

            result = toBeHashed;

        } else if (algo.equals("DESede")) {

            // if the 2 salt halves are the same, invert one of them

            int i;

            for (i=0; i<4; i++) {

                if (salt[i] != salt[i+4])

                    break;

            }

            if (i==4) { // same, invert 1st half

                for (i=0; i<2; i++) {

                    byte tmp = salt[i];

                    salt[i] = salt[3-i];

                }

            }

            // Now digest each half (concatenated with password). For each

            // half, go through the loop as many times as specified by the

            // iteration count parameter (inner for loop).

            // Concatenate the output from each digest round with the

            // password, and use the result as the input to the next digest

            // operation.

            byte[] kBytes = null;

            IvParameterSpec iv = null;

            byte[] toBeHashed = null;

            result = new byte[DESedeKeySpec.DES_EDE_KEY_LEN +

                              DESConstants.DES_BLOCK_SIZE];

            for (i = 0; i < 2; i++) {

                toBeHashed = new byte[salt.length/2];

                System.arraycopy(salt, i*(salt.length/2), toBeHashed, 0,

                                 toBeHashed.length);

                for (int j=0; j < iCount; j++) {

                    md.update(toBeHashed);

                    md.update(passwdBytes);

                    toBeHashed = md.digest(); // this resets the digest

                }

                System.arraycopy(toBeHashed, 0, result, i*16,

                                 toBeHashed.length);

            }

        }

        return result;

    }

    void init(int opmode, Key key, AlgorithmParameters params,

              SecureRandom random)

        throws InvalidKeyException, InvalidAlgorithmParameterException {

        PBEParameterSpec pbeSpec = null;

        if (params != null) {

            try {

                pbeSpec = params.getParameterSpec(PBEParameterSpec.class);

            } catch (InvalidParameterSpecException ipse) {

                throw new InvalidAlgorithmParameterException("Wrong parameter "

                                                             + "type: PBE "

                                                             + "expected");

            }

        }

        init(opmode, key, pbeSpec, random);

    }

    /**

     * Continues a multiple-part encryption or decryption operation

     * (depending on how this cipher was initialized), processing another data

     * part.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, are processed, and the

     * result is stored in a new buffer.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     *

     * @return the new buffer with the result

     *

     */

    byte[] update(byte[] input, int inputOffset, int inputLen) {

        return cipher.update(input, inputOffset, inputLen);

    }

    /**

     * Continues a multiple-part encryption or decryption operation

     * (depending on how this cipher was initialized), processing another data

     * part.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, are processed, and the

     * result is stored in the <code>output</code> buffer, starting at

     * <code>outputOffset</code>.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     * @param output the buffer for the result

     * @param outputOffset the offset in <code>output</code> where the result

     * is stored

     *

     * @return the number of bytes stored in <code>output</code>

     *

     * @exception ShortBufferException if the given output buffer is too small

     * to hold the result

     */

    int update(byte[] input, int inputOffset, int inputLen,

               byte[] output, int outputOffset)

        throws ShortBufferException {

        return cipher.update(input, inputOffset, inputLen,

                             output, outputOffset);

    }

    /**

     * Encrypts or decrypts data in a single-part operation,

     * or finishes a multiple-part operation.

     * The data is encrypted or decrypted, depending on how this cipher was

     * initialized.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, and any input bytes that

     * may have been buffered during a previous <code>update</code> operation,

     * are processed, with padding (if requested) being applied.

     * The result is stored in a new buffer.

     *

     * <p>The cipher is reset to its initial state (uninitialized) after this

     * call.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     *

     * @return the new buffer with the result

     *

     * @exception IllegalBlockSizeException if this cipher is a block cipher,

     * no padding has been requested (only in encryption mode), and the total

     * input length of the data processed by this cipher is not a multiple of

     * block size

     * @exception BadPaddingException if decrypting and padding is chosen,

     * but the last input data does not have proper padding bytes.

     */

    byte[] doFinal(byte[] input, int inputOffset, int inputLen)

        throws IllegalBlockSizeException, BadPaddingException {

        return cipher.doFinal(input, inputOffset, inputLen);

    }

    /**

     * Encrypts or decrypts data in a single-part operation,

     * or finishes a multiple-part operation.

     * The data is encrypted or decrypted, depending on how this cipher was

     * initialized.

     *

     * <p>The first <code>inputLen</code> bytes in the <code>input</code>

     * buffer, starting at <code>inputOffset</code>, and any input bytes that

     * may have been buffered during a previous <code>update</code> operation,

     * are processed, with padding (if requested) being applied.

     * The result is stored in the <code>output</code> buffer, starting at

     * <code>outputOffset</code>.

     *

     * <p>The cipher is reset to its initial state (uninitialized) after this

     * call.

     *

     * @param input the input buffer

     * @param inputOffset the offset in <code>input</code> where the input

     * starts

     * @param inputLen the input length

     * @param output the buffer for the result

     * @param outputOffset the offset in <code>output</code> where the result

     * is stored

     *

     * @return the number of bytes stored in <code>output</code>

     *

     * @exception IllegalBlockSizeException if this cipher is a block cipher,

     * no padding has been requested (only in encryption mode), and the total

     * input length of the data processed by this cipher is not a multiple of

     * block size

     * @exception ShortBufferException if the given output buffer is too small

     * to hold the result

     * @exception BadPaddingException if decrypting and padding is chosen,

     * but the last input data does not have proper padding bytes.

     */

    int doFinal(byte[] input, int inputOffset, int inputLen,

                byte[] output, int outputOffset)

        throws ShortBufferException, IllegalBlockSizeException,

               BadPaddingException {

        return cipher.doFinal(input, inputOffset, inputLen,

                                    output, outputOffset);

    }

    /**

     * Wrap a key.

     *

     * @param key the key to be wrapped.

     *

     * @return the wrapped key.

     *

     * @exception IllegalBlockSizeException if this cipher is a block

     * cipher, no padding has been requested, and the length of the

     * encoding of the key to be wrapped is not a

     * multiple of the block size.

     *

     * @exception InvalidKeyException if it is impossible or unsafe to

     * wrap the key with this cipher (e.g., a hardware protected key is

     * being passed to a software only cipher).

     */

    byte[] wrap(Key key)

        throws IllegalBlockSizeException, InvalidKeyException {

        byte[] result = null;

        try {

            byte[] encodedKey = key.getEncoded();

            if ((encodedKey == null) || (encodedKey.length == 0)) {

                throw new InvalidKeyException("Cannot get an encoding of " +

                                              "the key to be wrapped");

            }

            result = doFinal(encodedKey, 0, encodedKey.length);

        } catch (BadPaddingException e) {

            // Should never happen

        }

        return result;

    }

    /**

     * Unwrap a previously wrapped key.

     *

     * @param wrappedKey the key to be unwrapped.

     *

     * @param wrappedKeyAlgorithm the algorithm the wrapped key is for.

     *

     * @param wrappedKeyType the type of the wrapped key.

     * This is one of <code>Cipher.SECRET_KEY</code>,

     * <code>Cipher.PRIVATE_KEY</code>, or <code>Cipher.PUBLIC_KEY</code>.

     *

     * @return the unwrapped key.

     *

     * @exception NoSuchAlgorithmException if no installed providers

     * can create keys of type <code>wrappedKeyType</code> for the

     * <code>wrappedKeyAlgorithm</code>.

     *

     * @exception InvalidKeyException if <code>wrappedKey</code> does not

     * represent a wrapped key of type <code>wrappedKeyType</code> for

     * the <code>wrappedKeyAlgorithm</code>.

     */

    Key unwrap(byte[] wrappedKey,

               String wrappedKeyAlgorithm,

               int wrappedKeyType)

        throws InvalidKeyException, NoSuchAlgorithmException {

        byte[] encodedKey;

        try {

            encodedKey = doFinal(wrappedKey, 0, wrappedKey.length);

        } catch (BadPaddingException ePadding) {

            throw new InvalidKeyException("The wrapped key is not padded " +