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Provides a file system driver for accessing the RAES encrypted ZIP file format, alias ZIP.RAES or TZP. Add the JAR artifact of this module to the run time class path to make its file system drivers available for service location in the client API modules.

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/*
 * Copyright © 2005 - 2021 Schlichtherle IT Services.
 * All rights reserved. Use is subject to license terms.
 */
package net.java.truevfs.driver.zip.raes.crypto;

/**
 * This interfaces contains constants used to read or write files
 * according to the Random Access Encryption Specification (Constants).
 * Public classes must not implement this interface - otherwise the
 * constants become part of the public API.
 *
 * @author  Christian Schlichtherle
 */
interface Constants {

    /**
     * The signature of any Constants compatible content in little endian format
     * ({@code "Constants"} as a US-ASCII character sequence).
     */
    int SIGNATURE = 'R' | (('A' | (('E' | ('S' << 8)) << 8)) << 8);

    int HEADER_MIN_LEN =
            4 + // SIGNATURE
            1;  // Envelope type

    /**
     * The data envelope type used for password based encryption
     * with the same salt length as the cipher key length.
     */
    byte TYPE_0 = 0;

    /** The length of the header before the salt and the encrypted data. */
    int TYPE_0_HEADER_LEN_WO_SALT =
            HEADER_MIN_LEN +
            1 + // Cipher and MAC key strength.
            2;  // Iteration count
                // The salt which's length is the cipher key length.
                // The ciphered data which has the same length as the plain data.
                // The KLAC (first half of 256 bit SHA output = 128 bits).
                // The  MAC (first half of 256 bit SHA output = 128 bits).

    /**
     * The block size of the Advanced Encryption Specification (AES) Algorithm
     * in bits ({@value #AES_BLOCK_SIZE_BITS}).
     */
    int AES_BLOCK_SIZE_BITS = 128;
}