问题
I would like to give some kind of protection to my files either stored in SDCard or in application sandbox. Currently I am using Cipher to encrypt or decrypt any file. Problem with using Cipher is time. It takes lots of time if file is large. Like currently I am encrypting a video file which takes more than 4 minutes to decrypt. I want to know that Can we apply some kind of password protection to file without encrypting ? If anyone knows how can we do that, please let me know.
回答1:
Short answer is NO. That is not possible. File is on SD card stored as "array of 1 and 0" so each program can access SD card and read your data. Encryption is best way to keep your data secret.
来源：https://stackoverflow.com/questions/15742091/password-protection-of-file-in-android