it's not allowed to post hashes.
The encryption used by the PDF algorithm uses a 128 bit key.
This key is derived by a key-derivation-function and will be generated from your password as an input.
This means, that -m 10500 as most other algorithms (excepts some special hash types, see collider modes) expect the password as an input.
Therefore, you try password candidates. You can't easily break a 128 bit random key directly, but if it is derived from an (easy) password, it might be feasible/easy to open the PDF document.
The encryption used by the PDF algorithm uses a 128 bit key.
This key is derived by a key-derivation-function and will be generated from your password as an input.
This means, that -m 10500 as most other algorithms (excepts some special hash types, see collider modes) expect the password as an input.
Therefore, you try password candidates. You can't easily break a 128 bit random key directly, but if it is derived from an (easy) password, it might be feasible/easy to open the PDF document.