Update README.md

Author: h4ckyou

Cryptography/Onion/README.md

@@ -1 +1,24 @@
+## Onion
 
+Description: My radio only accepts readings in MHz. However, I managed to intercept some signals at 0.05 GHz<br>
+Solves: 5
+
+---
+Solution
+---
+
+We are given a file called `wav` which has a size of `44mb` that's oddly too large
+
+Checking the content reveals that it's likely a base64 encoded value
+
+After decoding we noticed that it gives another base64 encoded value
+
+This means this plaintext content was likely base64 encoded multiple times
+
+To solve I wrote a script to decoded the file till it isn't decodable
+
+Doing that gave the flag
+
+```
+Flag: csean-ctf{5l0w_5cr1pt}24
+```