maybe it's needed now
For those not familiar with RSA, it is a means by which two people can send each other information to establish a secret code ... and carry on that process publicly. Thus, they can make up a code between them which no one else can decipher even though anyone might intercept the communications by which they establish that code. They don't need to send a secret code by courier.
A bit code, on the other hand, is a graphic encryption method which requires a courier. I described it on this page... Text or Graphic Encryption?.
The protocol is as follows :
Every company or individual acquires a secret encode-decode "bit cypher" from Bit Masters (the encryption company). This company sends the individual a cd-rom through the mail with the program to code and decode messages with an included bit code. (The bit code is described on the above linked web page.)
The user installs this on his computer and is responsible for its security thereafter. A corporation with more to lose than an individual would send a courier to acquire the cd-rom in person with multiple codes for its staff and operations.
When an individual wants to buy something on the Web, his program encodes his sensitive data (soc sec number, visa card, mastercard, ets.) and sends it to Bit Masters which decodes it using their copy of the individual's personal bit code ... then ... re-encodes that data in the destination companies bit code and sends it to the company which then decodes it using their corresponding bit code and processes the information in the regular way. Vice versa for the return messages.
All of this is done by computers at Bit Masters. So the information is as safe as safe can be ... not perfectly safe ... just very safe. And ... it cannot, in principle be decoded by anyone intercepting the message. Therefore it is useful in commerce. To break the code one must steal the bit cypher somehow. It cannot be guessed or decrypted.
If your bit code is like A, you can probably be decoded. It's too simple and the permutations will probably yield just one message which is not jibberish.
If your bit code is B, you can start to breathe easy.
If your bit code is C, you can easily confound God Himself. It is unbreakable by any reasonable or even unreasonable means.
If your bit code is equal to the size your message, it is undecypherable, in principle, because it could form any number of sensible messages.
When you send a message, it might be good to put a background of random black and white pixels so as to further mask the message pixels. No background should touch the message because it would mess it up (especially small text). And ... I would advocate cutting the encrypted block into four squares and sending each of the four in random order so that every edge or center is disguised as one or the other. Reassemble the four pieces at destination.
Neither of these measures is really needed. I just mention them to be thorough.