AMPS offers end-to-end encryption, a unique feature to secure your data. Your file and relevant metadata are encrypted with randomly generated encryption keys, which are only possibly accessed by you or your recipients with unique private decryption keys. Therefore, nobody can access the stored data, aside from the owner and users authorized by the owner.
AMPS applies server side encryption AES-256 with CFB mode that might allow user to decide key to encrypt without client applications.
Note: the key is only available in user session. The key will be removed after user logout and server will not store the key.