mirror of https://github.com/vitalif/zbackup
57 lines
2.1 KiB
C++
57 lines
2.1 KiB
C++
// Copyright (c) 2012-2014 Konstantin Isakov <ikm@zbackup.org> and ZBackup contributors, see CONTRIBUTORS
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// Part of ZBackup. Licensed under GNU GPLv2 or later + OpenSSL, see LICENSE
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#ifndef ENCRYPTION_HH_INCLUDED
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#define ENCRYPTION_HH_INCLUDED
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#include <stddef.h>
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#include <exception>
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#include "ex.hh"
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/// What we implement right now is AES-128 in CBC mode with PKCS#7 padding
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namespace Encryption {
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enum
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{
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KeySize = 16, /// Size of the key in bytes
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IvSize = 16, /// Size of the IV data in bytes
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BlockSize = 16 /// Cipher block size in bytes
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};
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DEF_EX( exBadPadding, "Bad padding encountered", std::exception )
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/// Encrypts 'size' bytes of the data pointed to by 'in', outputting 'size'
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/// bytes to 'out'. 'key' points to KeySize bytes of the key data. 'iv' points
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/// to IvSize bytes used as an initialization vector. 'in' and 'out' can be the
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/// same. 'size' must be a multiple of BlockSize. Returns a pointer to the
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/// IV which should be used to continue encrypting, which in CBC is the last
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/// encrypted block
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void const * encrypt( void const * iv, void const * key, void const * in,
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void * out, size_t size );
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/// Returns a pointer to the IV which should be used to decrypt the block next
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/// to the given one, which in CBC is the last encrypted block. Note that if an
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/// in-place decryption is performed, this IV should be saved first, as it will
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/// be overwritten with the decrypted data. For size == 0, the returned pointer
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/// is invalid
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void const * getNextDecryptionIv( void const * in, size_t size );
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/// The reverse of encrypt()
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void decrypt( void const * iv, void const * key, void const * in, void * out,
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size_t size );
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/// Pads the last block to be encrypted, pointed to by 'data', 'size' bytes,
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/// which should be less than BlockSize, to occupy BlockSize bytes
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void pad( void * data, size_t size );
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/// Returns the size of the padded data. The data itself is unchanged - use the
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/// first bytes of 'data'. Can throw exBadPadding
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size_t unpad( void const * data );
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/// The IV consisting of zero bytes. Use it when there is no IV
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extern char const ZeroIv[ IvSize ];
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}
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#endif
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