3201fb4d83
* Changed implementation of AES to one which is almost 5 times as fast. The new implementation comes from LibTomCrypt. The newer implementation produces a larger binary size as a trade-off. * AES-CTR module now supports OpenMP and when compiled with OpenMP will run in parallel giving a much greater speed. * Changed interface for Initialisation functions for both AES and AES-CTR to be match RC4 (The context is first parameter not last)
141 lines
6.6 KiB
C
141 lines
6.6 KiB
C
////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// CryptLib_AesCtr
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//
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// Implementation of AES CTR stream cipher.
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//
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// Depends on: CryptoLib_Aes
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//
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// AES CTR is a stream cipher using the AES block cipher in counter mode.
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// This implementation works on both little and big endian architectures.
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//
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// This is free and unencumbered software released into the public domain - November 2017 waterjuice.org
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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#pragma once
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// IMPORTS
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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#include <stdint.h>
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#include "CryptLib_Aes.h"
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// TYPES
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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#define AES_CTR_IV_SIZE 8
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// TYPES
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrContext
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// Do not modify the contents of this structure directly.
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typedef struct
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{
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AesContext Aes;
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uint8_t IV [AES_CTR_IV_SIZE];
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uint64_t StreamIndex;
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uint64_t CurrentCipherBlockIndex;
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uint8_t CurrentCipherBlock [AES_BLOCK_SIZE];
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} AesCtrContext;
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// PUBLIC FUNCTIONS
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrInitialise
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//
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// Initialises an AesCtrContext with an already initialised AesContext and a IV. This function can quickly be used
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// to change the IV without requiring the more length processes of reinitialising an AES key.
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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void
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AesCtrInitialise
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(
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AesCtrContext* Context, // [out]
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AesContext const* InitialisedAesContext, // [in]
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uint8_t const IV [AES_CTR_IV_SIZE] // [in]
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);
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrInitialiseWithKey
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//
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// Initialises an AesCtrContext with an AES Key and an IV. This combines the initialising an AES Context and then
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// running AesCtrInitialise. KeySize must be 16, 24, or 32 (for 128, 192, or 256 bit key size)
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// Returns 0 if successful, or -1 if invalid KeySize provided
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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int
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AesCtrInitialiseWithKey
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(
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AesCtrContext* Context, // [out]
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uint8_t const* Key, // [in]
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uint32_t KeySize, // [in]
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uint8_t const IV [AES_CTR_IV_SIZE] // [in]
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);
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrSetStreamIndex
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//
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// Sets the current stream index to any arbitrary position. Setting to 0 sets it to the beginning of the stream. Any
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// subsequent output will start from this position
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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void
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AesCtrSetStreamIndex
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(
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AesCtrContext* Context, // [in out]
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uint64_t StreamIndex // [in]
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);
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrXor
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//
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// XORs the stream of byte of the AesCtrContext from its current stream position onto the specified buffer. This will
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// advance the stream index by that number of bytes.
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// Use once over data to encrypt it. Use it a second time over the same data from the same stream position and the
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// data will be decrypted.
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// InBuffer and OutBuffer can point to the same location for in-place encrypting/decrypting
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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void
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AesCtrXor
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(
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AesCtrContext* Context, // [in out]
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void const* InBuffer, // [in]
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void* OutBuffer, // [out]
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uint32_t Size // [in]
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);
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrOutput
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//
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// Outputs the stream of byte of the AesCtrContext from its current stream position. This will advance the stream
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// index by that number of bytes.
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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void
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AesCtrOutput
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(
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AesCtrContext* Context, // [in out]
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void* Buffer, // [out]
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uint32_t Size // [in]
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);
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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// AesCtrXorWithKey
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//
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// This function combines AesCtrInitialiseWithKey and AesCtrXor. This is suitable when encrypting/decypting data in
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// one go with a key that is not going to be reused.
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// This will used the provided Key and IV and generate a stream that is XORed over Buffer.
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// Returns 0 if successful, or -1 if invalid KeySize provided
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////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
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int
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AesCtrXorWithKey
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(
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uint8_t const* Key, // [in]
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uint32_t KeySize, // [in]
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uint8_t const IV [AES_CTR_IV_SIZE], // [in]
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void const* InBuffer, // [in]
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void* OutBuffer, // [out]
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uint32_t BufferSize // [in]
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);
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