Most significant bit (MSB) in ASCII code

Cylab

Hello

You know that the MSB in each byte is always zero in ASCII code (e.g. text file).
If I cut the text file by byte, then there will be 0 (which is MSB) that might reveal some information... So, are there any stochastic rules that I make the strings random in ASCII code?

It will be helpful, if anyone will provide me some ways to make strings into randome or anything at all that will be hint.

Thanks in advance for your reading.

HallsofIvy

It might help if you would explain what you mean by "make a string random".

Cylab

Sorry for being late....the point is how to make the Most significant bit appear anywhere in a sequence...(not using encryption)