Encrypted Files in Minix 3

Implemented encrypted files in Minix 3. The cipher used is simple Caesar's cipher.

Description

Implemented a new system call in Minix 3 along with the library function that allows it to be called conveniently from a C program. The library interface extends extends file access operations to handle encrypted files.

Reading and writing to a file is done through a system call. The first is to access the "master encryption table" file (/etc/encryptTable) that stores the information about every file that is encrypted within Minix and contains three pieces of information: fs_dev, inode_nr and hashed_pw. The first two information uniquely identifies what file is encrypted and can be obtained from the vnode for the file.

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