title: Encryption algorithm that output byte by byte based on password and offset
body: <p>Is there a well-known (to be considered) algorithm that can encrypt/decrypt any arbitrary byte inside the file based on the password entered and the offset inside the file. </p>
  
  <pre><code>(Databyte, Offset, Password) =&gt; EncryptedByte
  (EncryptedByte, Offset, Password) =&gt; DataByte
  </code></pre>
  
  <p>And is there some fundamental weakness in this approach or it's still theoretically possible to build it strong enough</p>
  
  <p>Update: 
  More datails: Any cryptographic algorithm has input and output. For many existing ones the input operates on large blocks. I want to operate on only one byte, but the system based on this can only can remap bytes and weak by default, but if we take the position in the file of this byte, we for example can take the bits of this position value to interpret them as some operation on some step (0: xor, 1: shitf) and create the encrypted byte with this. But it's too simple, I'm looking for something stronger.</p>