S-DES Binary converted to ASCII?
Encoded Binary Value: 11000001 (Is this regarded as the ciphertext?)


Yes. Or at least it is considered a block of ciphertext, as in, the output of a block cipher. A block cipher in itself is not a CPA secure cipher, as identical input messages (plaintext) will lead to identical output.


  Finally convert, the encoded binary value back to ASCII: ? (Could someone please explain how this is done?)


You look up 0110 on the top row listing the high order bits, and then lookup 0101 in the low order bits, so you'll find the lower case e again. Of course most computer languages have functions such as CHR$ to do this for you.