Can someone explain why this decrypt works?

using the library crypto-js, I encrypt the string 'goat'.The encrypted sting is something like thiskhsfg935j+353klhddg98= Decrypting using the same secret key, I get 'goat'. If I delete the = and decrypt it using the same secret key, I get 'goat'. Deleting anything more than the =, it does not decrypt. Does the = character not playing any role in terms of decrypting?

Submitted May 17, 2018 at 06:13PM by eggtart_prince