77 lines
2.5 KiB
C++
77 lines
2.5 KiB
C++
/*
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* File: AESKey.cpp
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*
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* Copyright (c) Freescale Semiconductor, Inc. All rights reserved.
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* See included license file for license details.
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*/
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#include "AESKey.h"
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#include <stdexcept>
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#include "smart_ptr.h"
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#include "HexValues.h"
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#include <ctype.h>
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//! The data from the stream is expected to be hex encoded. Each two characters
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//! from the stream encode a single result byte. All non-hexadecimal characters
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//! are ignored, including newlines. Every two hexadecimal characters form
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//! an encoded byte. This is true even if the two characters representing the
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//! upper and lower nibbles are separated by whitespace or other characters.
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//!
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//! \post The stream read head is left pointing just after the last encoded byte.
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//!
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//! \param stream Input stream to read from.
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//! \param bytes Number of encoded bytes to read. This is the number of \e
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//! result bytes, not the count of bytes to read from the stream.
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//! \param[out] buffer Pointer to the buffer where decoded data is written.
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//!
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//! \exception std::runtime_error This exception will be thrown if less
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//! data than required is available from \a stream, or if some other
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//! error occurs while reading from \a stream.
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void AESKeyBase::_readFromStream(std::istream &stream, unsigned bytes, uint8_t *buffer)
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{
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char temp[2];
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char c;
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char n = 0;
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while (bytes)
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{
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if (stream.get(c).fail())
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{
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throw std::runtime_error("not enough data in stream");
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}
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if (isHexDigit(c))
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{
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temp[n++] = c;
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if (n == 2)
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{
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*buffer++ = hexByteToInt(temp);
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bytes--;
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n = 0;
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}
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}
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}
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}
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//! Key data is written to \a stream as a sequence of hex encoded octets, each two
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//! characters long. No spaces or newlines are inserted between the encoded octets
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//! or at the end of the sequence.
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//!
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//! \exception std::runtime_error Thrown if the \a stream reports an error while
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//! writing the key data.
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void AESKeyBase::_writeToStream(std::ostream &stream, unsigned bytes, const uint8_t *buffer)
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{
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const char hexChars[] = "0123456789ABCDEF";
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while (bytes--)
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{
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uint8_t thisByte = *buffer++;
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char byteString[2];
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byteString[0] = hexChars[(thisByte & 0xf0) >> 4];
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byteString[1] = hexChars[thisByte & 0x0f];
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if (stream.write(byteString, 2).bad())
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{
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throw std::runtime_error("error while writing to stream");
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}
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}
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}
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