電腦file可唔可以設定密碼?

你可以裝 True Crypt
Creates a virtual encrypted disk within a file and mounts it as a real disk.
Encrypts an entire partition or storage device such as USB flash drive or hard drive.
Encrypts a partition or drive where Windows is installed (pre-boot authentication).
Encryption is automatic, real-time (on-the-fly) and transparent.
Provides two levels of plausible deniability, in case an adversary forces you to reveal the password:

1) Hidden volume (steganography – more information may be found here).

2) No TrueCrypt volume can be identified (volumes cannot be distinguished from random data).


Encryption algorithms: AES-256, Serpent, and Twofish. Mode of operation: XTS.
Further information regarding features of the software may be found in the documentation

http://www.truecrypt.org/