Merge pull request #5 from blacklanternsecurity/dev

Document anchorBlock IV mode in example.ini

Author: liquidsec

example.ini

@@ -68,7 +68,9 @@ cookies = {}
 # 'firstblock'. This mode assumes that the first block of the ciphertext is the IV (most common)
 # 'knownIV'. This mode allows for user provided IV
 # 'unknown'. Use this mode when you do not know the IV and it is not the first block but still wish to decrypt all but the first block, or re-encrypt all but the first block for encryption
-# 'lastblock'. This has not been implemented yet, but it may be in the future as it is a rare but possible configuration
+# 'anchorBlock'. Use this mode when you have a separate, known-valid ciphertext whose first block
+#   should be used as the IV/anchor. This is useful for encryption mode when you need a valid first
+#   block from an existing ciphertext to anchor the new encrypted payload. Requires anchorCiphertext.
 
 
 # choose from one of the above modes
@@ -77,6 +79,10 @@ ivMode = firstblock
 #IV should be in decimal list format. For example: [72,65,82,65,77,66,69]
 iv =  [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0]
 
+# If using anchorBlock mode, specify the anchor ciphertext (encoded in the same format as encodingMode)
+# The first block of this ciphertext will be extracted and used as the IV.
+anchorCiphertext =
+
 # The oracle defines the information leak that is abused to know when padding is valid. This is typically an error message.
 # There are several trigger modes depending on the situation. Sometimes you will want to look for a specific phrase, other times you want to look for an absence of that phrase.