The key used to lock the file is generated locally on the uploader's device. MEGA's servers host the encrypted data but do not have a copy of the key.
Think of it like a physical safe. The link you click is the address of the safe, and the decryption key is the unique combination needed to open it. Without the combination, you can stare at the safe all you want, but its contents will remain inaccessible. This fundamental design is why a decryption key bypass is cryptographically infeasible. how to open a mega link without decryption key link
A standard MEGA link contains two parts: the file identifier and the unique decryption key. They are usually separated by a hashtag ( # ) or an exclamation mark ( ! ). The key used to lock the file is