In an early post, Simple Encryption Methods, I mentioned 4 kinds of bitwise level operations that could be used to encrypt data. Between them was, mask, inverse, reverse and rotate. If you want speed its good to remember that the more complex the more processing time it has to be done yet it normally also means that it is more secure. Mixing several kinds of operations can be a good idea. if only you know the order it would be like the formula itself is a giant password. But also, if you want security its a good thing not to use the same process with each word, that would just generate an alternate alphabet that can be easily decrypted by using word associations. So you need to vary your methods in a way a pattern its difficult to recognize. So we start by mixing the methods. We need a formula that tells what methods to use, so the lowest form would be, if the method will be used or not used. Also we can alter the order of the methods this can create a large amount of possibilities. But first we have to know, that when using this 4 kinds of methods the inverse one can be anywhere. And therefore should be used once.
Its easy to identify why rotate and reverse don't matter when you did the inverse (if before or after.
1100 rotated once 1001 and then inversed 0110
1100 inversed 0011 rotated once 0110
1100 reversed 0011 inversed 1100
1100 inversed 0011 reversed 1100
note that in combinations inverse and reverse will return the same, but this is not true for all values.
mask also have this property lets see at a simple test
1100 masked with 1010 is 0110 inversed is 1001
1100 inversed is 0011 masked with 1010 is 1001
this has been tested with all possible combinations and is true for all.
therefore we don't need to care about the position of the inverse only if it exist or not
inverse rotate reverse masked is the same as rotate inverse reverse masked and therefore is the same as rotate reverse inverse masked and therefore is the same as rotate reverse masked inverse.
Yet on further testing the position between rotate reverse and masked, does matter, So its a good thing to play with their order when building an encryption method. Also since the position of inverse doesn't mater don't go around making more than one inverse because two inverse is the same as no inverse.
Remember you can get creative with the formula of encryption a nice idea is to force an order of encryption, by using a formula that generates values for each letter that affect the way they are encrypted and by using the letter before as a value to alter the encryption. This way ensures that not only you need to know the method and the formula, but you need to encrypt in an order, and the encryption depends on the message itself making it hard to identify a pattern between two messages.
Wednesday, April 9, 2008
A step further in encryption
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