How can I create a stream cipher from a block cipher? Assuming $k$ is the key (128 bit) and $m$ is the message (128 bit), how can I use the block cipher $blockenc(k,m)$ to make a stream cipher which can produce quintillion pseudo-random bits?
There are 3 modes of operation which make a stream cipher out of a block cipher:


Cipher Feedback Mode,
Output Feedback Mode, and 
Counter Mode.


Taking example of the Counter Mode, this is how encryption and decryption works

$$C_i = P_i \oplus BlockEnc_k(count)\\
P_i = C_i \oplus BlockEnc_k(count)$$
$count$ is increased by 1 with every
 byte of the stream.