alt Hacker NewsThe operations used to perform these computations are utilizing algorithms backed by lattice-problems that are NP-hard to break.
edit: The only leaking information in this case are what operations you'd like to perform on the encrypted data. e.g., you now know that you've incremented the password by x amount, but you don't know what the plaintext was before, the plaintext after, _or_ infer what the value is by knowing you've modified the encrypted data by x amount.
edit2: Now I think I understand the question. The encryption is technically weakened because you can know what operations are made on the underlying data. Though it's still an advancing field, and there are promising developments with what's called circuit privacy[0] to prevent the server knowing the operations made as well.