In this challenge, we have a long text file.
We can see that it ends with VldwR1MxSXhVbk5YYlhSWFRWZFNSMVV5ZUdGV01rcFpZVVpvV0Zac2NGaGFSVnBYVjFkR1IxTnRiRk5YUlVwVVZtMHhNRlV4Um5KUFZrcFJWa1JCT1E9PQ==
It looks like base64!
I decoded it, but again, the content was base64 encoded.
so I created a simple python script that recursively decodes base64:

```
#! /usr/bin/env python3
import base64
with open('ciphertext', 'r') as content:
text = content.read()
while 1:
try:
text = base64.b64decode(text)
except:
print(text)
break
```

and our flag is:

'UMDCTF-{b@se64_15_my_f@v0r1t3_b@s3}'