RSA, ECB and CBC implementation

[vegancoder]

Hello folks,

I am currently studying a Network Man. and Security course and we've been asked to implement RSA encryption using cipher block chaining mode or electronic code block mode.

I have a fair understaning of how RSA works and i reckon that bit is fibe but what im not sure about is how do i get the blocks to encrypt? Im supposed to use 24 bit blocks and have a 7 letter word to encrypt.

So i reckon there will be, with some padding, 3 blocks in total that i need to encrypt.

So far i have been encryptinmg single charcaters and this was easy because i simply converted it into the ascii value and fed it into the encryption function. So im not sure how to encrypt 3 characters at once.

I need to understand how to do this.

Can anyone help?

[r-ID]

http://en.wikipedia.org/wiki/Block_ciph ... _operation

you encrypt 3 chars the same as you encrypt 1 char, you just pass a string to the function and it gets encrypted some encryption modes support streaming, that means encripted string might be different and the result depends on the time you encrypt it.