The fully undetectable crypter or FUD is a type of crypter that can bypass antivirus or security programs. In this case, Data Encoder Crypter encrypts any data so hide it from any detection. Programmers use several methods to encrypt data notably. As a result, the crypter output bypass detections.
Fully undetectable Crypter
In short, Crypter needs to bypass two stages of antivirus detection, namely Scantime and Runtime. Firstly it encrypts data with a legit process so the EXE file runs on the target system. For example, The Scantime step is when the file is not executed. So, the Runtime step is when the file is running.