encryption and decryption

[11max11]

hihi...
can i ask for encryption and decryption information??

because i don't how to start..
is that start from eeprom?

i using the mplab ide.

 

[Nigel Goodwin]

Your question is far too vague to give any meaningful answer to, what do you actually want to know?.

Two of my tutorials (IR and Wireless) meet that requirement, but I've no idea if that's what you want?.

 

[11max11]

hihi..
i want to know is how to built the code...

 

[mramos1]

Try this link for a start.

**broken link removed**

More sample code here..

**broken link removed**

 

[11max11]

hihi
the first one is useful for me but the second website is using the C++...

but anywhere really thx for mramos1....

 

[11max11]

hihi...
can anyone show me the encryption and decryption source code..

 

[Papabravo]

You might want to look at PGP - Pretty Good Privacy for some idea of how encryption and decryption works

PGP was based on RSA (Rivest-Shamir-Adelman)

It involves the prime factors of very large numbers, and the ability to do arithmetic with an essentially unlimited number of digits.

 

[mramos1]

The first link is decryption. If you reverse the logic you have the encryption side. How encrypted do you need it? What level of person will be tring to unlock the data.

 

[11max11]

hihi...
i want a basic one then try my best to improve it...

 

[Pommie]

Well, simplest would be something like setting bit 7 of each byte. Next would come xoring each byte with 0x55. If you wanted to, you could swap some bits around - say swap bits 5 and 2. Then there would be using a pseudo random number generator to produce numbers that you xor each byte with.

The list is endless.

Some more information on the data being encrypted would help.

Mike.

 

[11max11]

hihi...
can show me some sample code?
because i'm newbie in PIC and just learn MPLAB IDE...

 

[Papabravo]

I guess factoring a 100 digit prime number will be a bit beyond a PIC's and your capabilities for the moment.

You could also use a table lookup. For each plain text letter lookup a code letter. The invers table is also easy to construct. For each codetext letter lookup the plaintext letter.

 

[Pommie]

I guess factoring a 100 digit prime number will be a bit beyond a PIC's and your capabilities for the moment.

You could also use a table lookup. For each plain text letter lookup a code letter. The invers table is also easy to construct. For each codetext letter lookup the plaintext letter.

I thought that the whole point is that you don't have to factorise. You simply divide the public key by your private key to get the new key.

BTW, I can factorise any 100 digit prime number with a Pic. In fact, I can do it in my head.

Mike.

 

[Leftyretro]

Actually one simple encryption method, which is also very secure, is the use of a 'one time pad'.

Just create and store a random key of bytes equal to the length of the message you wish to send. Give the receiver the random key in advance of sending the message. Exclusive OR the message and the pad and send the encrypted message. The receiver then does an exclusive OR with the encrypted message with his copy of the key and the original message will be recreated.

Use the key only once and the message is uncrackable without access to the key used, now or forever in the future, regardless of Moore's law.

Lefty

 

[arslan87]

hi anybody tell me the circuit diagram of encryption and decryption of voice in pstn
which works correctly
and also algorithm work in it
arslan_369@hotmail.com