Unix in a Nutshell, 4th Edition

Name

encrypt

Synopsis

    encrypt [options] [-i infile] [-o outfile]

Encrypt files using a PKCS#11 algorithm. Files are decrypted with decrypt. encrypt and decrypt are hard links to each other and accept the same options. Both programs read and write standard input and standard output by default. See also decrypt, digest, and mac.

Tip

These programs are not related to the original Unix crypt command. That program’s encryption algorithm is considered weak by today’s standards, and it should not be used.

Options

-a algorithm

Use algorithm to encrypt the file. Possible values for algorithm are aes, arcfour, des, and 3des.

-i file

Read input data from file, instead of from standard input.

-k keyfile

Read the encryption/decryption key from keyfile, instead of prompting for it.

-l

List available encryption algorithms. This option should be used by itself.

-o file

Write output data to file, instead of to standard output.

-v

Be verbose. This prints a progress bar.

Examples

Display available algorithms:

    $ encrypt -l
    Algorithm       Keysize:  Min   Max (bits)
    ------------------------------------------
    aes                       128   128
    arcfour                     8   128
    des                        64    64
    3des                      192   192

Encrypt a trade secret document, then decrypt it and compare the result to the original:

    $ encrypt -a aes -i designdoc.txt -o designdoc.txt.aes 
                     Encrypt
    Enter key:                                     Key is not echoed
    $ file design*                                 
                     Check results
    designdoc.txt:     ASCII text
    designdoc.txt.aes: data
    $ decrypt -a aes -i designdoc.txt.aes -o designdoc.txt.out
                     Decrypt
    Enter key:                                     Enter same key
    $ cmp designdoc.txt ...