Best array population & access optimization

[Mark Brownell]

On Friday, June 20, 2003, at 07:21  PM, Dar Scott wrote:

> However, since Blowfish primitives are xor and addition and since most 
> signed numbers are 2-complement it might not matter.
>
> Even so, in Revolution once you bitAnd or bitXor, I would have 
> expected unsigned values.  I have only seen signed values come up in 
> some uses of baseCovert().

It took a while and I was curious to see for myself, You were correct 
about expecting unsigned values. I ran a comparison version with the 
P-array from the C source code for encrypt and the P-array from the VB 
source code on decrypt and it worked. They were different in respect to 
signed numbers only. Only the unsigned numbers in the different source 
P-boxes were identical.

I changed out the (C sourced S-box-1) for the (VB sourced S-box-1) in 
both the encrypt and decrypt handlers. It worked. The complimentary 
signed numbers mattered in the S1-boxes as long as the same version 
S-box was used for encrypt and decrypt. It showed that S-box-1-VB works 
with S-box-2-C, S-box-3-C, and S-box-4-C where only the unsigned 
numbers in the two S-box-1 versions were identical.

Mark


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