Not So Simple Cipher  - Cryptography Challenge 

For this challenge we have a file that contains a long string of characters. After analysis of the string I could determinate that the string is in hexadecimal.

Once this string decoded we got another string of character but in base64 this time. Then, when I decoded again this new string there was another string in base64.

To simply explain, the decryption process is as follows:

Nssc.txt -> hexadecimal -> base64 -> base64 -> base64 -> base64 -> base64 -> hexadecimal -> base64

At this point, the result obtained seems to be very similar to the pattern got in the hint, STRING1_STRING2. But as the decryption in hexadecimal didn't work, so, I've decided to continue my research on these two new strings.

After investigation, these two strings are hashed in SHA1.

So I tried to crack the keys on a specialized site, and it worked!