JUCE/modules/juce_cryptography/encryption/juce_BlowFish.h

/*
  ==============================================================================

   This file is part of the JUCE library.
   Copyright (c) 2017 - ROLI Ltd.

   JUCE is an open source library subject to commercial or open-source
   licensing.

   By using JUCE, you agree to the terms of both the JUCE 5 End-User License
   Agreement and JUCE 5 Privacy Policy (both updated and effective as of the
   27th April 2017).

   End User License Agreement: www.juce.com/juce-5-licence
   Privacy Policy: www.juce.com/juce-5-privacy-policy

   Or: You may also use this code under the terms of the GPL v3 (see
   www.gnu.org/licenses).

   JUCE IS PROVIDED "AS IS" WITHOUT ANY WARRANTY, AND ALL WARRANTIES, WHETHER
   EXPRESSED OR IMPLIED, INCLUDING MERCHANTABILITY AND FITNESS FOR PURPOSE, ARE
   DISCLAIMED.

  ==============================================================================
*/

namespace juce
{

//==============================================================================
/**
    BlowFish encryption class.


    @tags{Cryptography}
*/
class JUCE_API  BlowFish
{
public:
    //==============================================================================
    /** Creates an object that can encode/decode based on the specified key.

        The key data can be up to 72 bytes long.
    */
    BlowFish (const void* keyData, int keyBytes);

    /** Creates a copy of another blowfish object. */
    BlowFish (const BlowFish&);

    /** Copies another blowfish object. */
    BlowFish& operator= (const BlowFish&) noexcept;

    /** Destructor. */
    ~BlowFish() noexcept;

    //==============================================================================
    /** Encrypts a pair of 32-bit integers. */
    void encrypt (uint32& data1, uint32& data2) const noexcept;

    /** Decrypts a pair of 32-bit integers. */
    void decrypt (uint32& data1, uint32& data2) const noexcept;

    //==============================================================================
    /** Encrypts a memory block */
    void encrypt (MemoryBlock& data) const;

    /** Decrypts a memory block */
    void decrypt (MemoryBlock& data) const;

    //==============================================================================
    /** Encrypts data in-place

        @param buffer       The message that should be encrypted. See bufferSize on size
                            requirements!
        @param sizeOfMsg    The size of the message that should be encrypted in bytes
        @param bufferSize   The size of the buffer in bytes. To accommodate the encrypted
                            data, the buffer must be larger than the message: the size of
                            the buffer needs to be equal or greater than the size of the
                            message in bytes rounded to the next integer which is divisible
                            by eight. If the message size in bytes is already divisible by eight
                            then you need to add eight bytes to the buffer size. If in doubt
                            simply use bufferSize = sizeOfMsg + 8.

        @returns            The size of the decrypted data in bytes or -1 if the decryption failed.
     */
    int encrypt (void* buffer, size_t sizeOfMsg, size_t bufferSize) const noexcept;

    /** Decrypts data in-place

        @param buffer  The encrypted data that should be decrypted
        @param bytes   The size of the encrypted data in bytes

        @returns       The size of the decrypted data in bytes or -1 if the decryption failed.
    */
    int decrypt (void* buffer, size_t bytes) const noexcept;

private:
    //==============================================================================
    static int pad   (void*, size_t, size_t) noexcept;
    static int unpad (const void*, size_t) noexcept;

    bool apply (void*, size_t, void (BlowFish::*op) (uint32&, uint32&) const) const;

    //==============================================================================
    uint32 p[18];
    HeapBlock<uint32> s[4];

    uint32 F (uint32) const noexcept;

    JUCE_LEAK_DETECTOR (BlowFish)
};

} // namespace juce