/// <summary> Decrypts a message </summary>
/// <param name="message"> Byte[] to decrypt </param>
/// <param name="index"> Index to begin copy from. Negative numbers behave like 0. </param>
/// <param name="length"> Length of characters to copy. Negative numbers/0 take the rest of the array. </param>
/// <returns> Decrypted copy of byte[] segment </returns>
public byte[] Decrypt(byte[] message, int index = -1, int length = -1)
{
if (index < 0)
{
index = 0;
}
if (length < 1)
{
length = message.Length - index;
}
byte[] dec = new byte[length];
for (int i = 0; i < length; i++)
{
byte b = message[index + i];
long hash = SRNG.hash(decPos++);
byte encDiff = (byte)hash;
byte encKey = (byte)(hash >> 8);
b ^= encKey;
b -= encDiff;
dec[i] = b;
if (b == EOT)
{
decPos = START;
}
}
return(dec);
}
/// <summary> Decrypts a segment of a Byte[], in place. </summary>
/// <param name="message"> Byte[] to decrypt </param>
/// <param name="index"> Index to begin decryption at. Negative numbers behave like 0. </param>
/// <param name="length"> Length of Byte[] segment to decrypt. Negative numbers/0 encrypt from index to the end. </param>
public void DecryptInPlace(byte[] message, int index = -1, int length = -1)
{
if (index < 0)
{
index = 0;
}
if (length < 01)
{
length = message.Length - index;
}
for (int i = 0; i < length; i++)
{
byte b = message[index + i];
long hash = SRNG.hash(decPos++);
byte encDiff = (byte)hash;
byte encKey = (byte)(hash >> 8);
b ^= encKey;
b -= encDiff;
message[index + i] = b;
if (b == EOT)
{
decPos = START;
}
}
}
/// <summary> Encrypts a message </summary>
/// <param name="message"> Byte[] to encrypt </param>
/// <param name="index"> Index to begin copy from. Negative numbers behave like 0. </param>
/// <param name="length"> Length of Byte[] to copy. Negative numbers/0 take the rest of the array. </param>
/// <returns> Encrypted copy of Byte[] segment </returns>
public byte[] Encrypt(byte[] message, int index = -1, int length = -1)
{
if (index < 0)
{
index = 0;
}
if (length < 1)
{
length = message.Length - index;
}
byte[] enc = new byte[length];
for (int i = 0; i < length; i++)
{
byte b = (message[index + i]);
bool wasEOT = (b == EOT);
long hash = SRNG.hash(encPos++);
byte encDiff = (byte)hash;
byte encKey = (byte)(hash >> 8);
b += encDiff;
b ^= encKey;
enc[i] = b;
if (wasEOT)
{
encPos = START;
}
}
return(enc);
}
/// <summary> Encrypts a segment of a Byte[], in place. </summary>
/// <param name="message"> Byte[] to encrypt</param>
/// <param name="index"> Index to begin encryption at. Negative numbers behave like 0. </param>
/// <param name="length"> Length of Byte[] segment to encrypt. Negative numbers/0 encrypt from index to the end. </param>
public void EncryptInPlace(byte[] message, int index = -1, int length = -1)
{
if (index < 0)
{
index = 0;
}
if (length < 1)
{
length = message.Length - index;
}
for (int i = 0; i < length; i++)
{
byte b = message[index + i];
bool wasEOT = (b == EOT);
long hash = SRNG.hash(encPos++);
byte encDiff = (byte)hash;
byte encKey = (byte)(hash >> 8);
b += encDiff;
b ^= encKey;
message[index + i] = b;
if (wasEOT)
{
encPos = START;
}
}
}
public static long[] TEST_GENERATE_SEQUENCE(int size = 512)
{
long[] vals = new long[size];
long pos = EncDec.START;
for (int i = 0; i < size; i++)
{
pos = SRNG.hash(pos);
vals[i] = pos;
}
return(vals);
}