87 lines
2.8 KiB
C++
Executable File
87 lines
2.8 KiB
C++
Executable File
// last modified Friday, May 09, 2003
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#include "Encryption.h"
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//--------------------------------------------------------------------
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// EncryptData - Takes A pointer to data in memory, the length of that data,
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// Along with a key in memory and its length. It will allocated space
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// for the encrypted copy of the data via new[], It is the responsiblity of the user
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// to call delete[].
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//--------------------------------------------------------------------
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_byte *EncryptData(_byte *Data, _long DataLength, _byte *Key, _long KeyLength)
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{
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// Allocate space for new Encrypted data
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_byte *NewData = new _byte[DataLength];
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// A counter to hold our absolute position in data
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_long DataOffset = 0;
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// Loop through Data until end is reached
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while (DataOffset < DataLength)
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{
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// Loop through the key
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for (_long KeyOffset = 0; KeyOffset < KeyLength; KeyOffset++)
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{
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// If were at end of data break and the the while loop should end as well.
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if (DataOffset >= DataLength)
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break;
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// Otherwise Add the previous element of the key from the newdata
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// (just something a little extra to confuse the hackers)
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if (KeyOffset > 0) // Don't mess with the first byte
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NewData[DataOffset] += Key[KeyOffset - 1];
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// Xor the Data byte with the key byte and get new data
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NewData[DataOffset] = Data[DataOffset] ^ Key[KeyOffset];
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// Increase position in data
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DataOffset++;
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}
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}
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// return the new data
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return NewData;
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}
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//--------------------------------------------------------------------
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// DecryptData - Takes A pointer to data in memory, the length of that data,
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// Along with a key in memory and its length. It will allocated space
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// for the decrypted copy of the data via new[], It is the responsiblity of the user
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// to call delete[].
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//--------------------------------------------------------------------
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_byte *DecryptData(_byte *Data, _long DataLength, _byte *Key, _long KeyLength)
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{
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// Allocate space for new Decrypted data
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_byte *NewData = new _byte[DataLength];
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// A counter to hold our absolute position in data
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_long DataOffset = 0;
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// Loop through Data until end is reached
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while (DataOffset < DataLength)
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{
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// Loop through the key
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for (_long KeyOffset = 0; KeyOffset < KeyLength; KeyOffset++)
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{
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// If were at end of data break and the the while loop should end as well.
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if (DataOffset >= DataLength)
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break;
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// Otherwise Xor the Data byte with the key byte and get new data
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NewData[DataOffset] = Data[DataOffset] ^ Key[KeyOffset];
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// Subtract the previous element of the key from the newdata
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// (just something a little extra to confuse the hackers)
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if (KeyOffset > 0) // Don't mess with the first byte
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NewData[DataOffset] -= Key[KeyOffset - 1];
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// Increase position in data
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DataOffset++;
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}
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}
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// return the new data
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return NewData;
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}
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