How-to-encrypt-file-with-passphrase

How to encrypt file with passphrase.

DESCRIPTION

Mcrypt is a simple crypting program, a replacement for the old unix crypt(1). When encrypting or ecrypting a file, a new file is created with the extension .nc and mode 0600. The new file keeps the modification date of the original. The original file may be deleted by specifying the -u parameter. If no files are specified, the standard input is encrypted to the standard output.

     Mcrypt uses all the symmetric algorithms included in libmcrypt.

     Use the command mcrypt

     shibu@shibu-laptop:~/Desktop$ mcrypt -uz  ubuntuforenterprise

     Enter the passphrase (maximum of 512 characters)
     Please use a combination of upper and lower case letters and numbers.
     Enter passphrase: 
     Enter passphrase: 

     File ubuntuforenterprise was encrypted.

     shibu@shibu-laptop:~/Desktop$ ls
     ubuntuforenterprise.gz.nc
     shibu@shibu-laptop:~/Desktop$ file ubuntuforenterprise.gz.nc 
     ubuntuforenterprise.gz.nc: mcrypt 2.5 encrypted data, 
     algorithm: rijndael-128, keysize: 32 bytes, mode: cbc,

$ mcrypt --help

      Mcrypt encrypts and decrypts files with symmetric encryption algorithms.

      Usage: mcrypt [-dFusgbhLvrzp] [-f keyfile] [-k key1 key2 ...] [-m mode] [-o keymode] [-s keysize] 
      [-a  algorithm] [-c config_file] [file ...]

     -g, --openpgp            Use the OpenPGP (RFC2440) file format.
     --openpgp-z INTEGER      Sets the compression level for openpgp 
                              packets (0 disables).
     -d, --decrypt            decrypts.
     -s, --keysize INTEGER    Set the algorithm's key size (in 
                              bytes).
     -o, --keymode KEYMODE    Specify the keyword mode. Use the 
                              --list-keymodes parameter to view all 
                              modes.
     -f, --keyfile FILE       Specify the file to read the keyword 
                              from.
     -c, --config FILE        Use configuration file FILE.

     -z, --gzip               Use gzip to compress files before 
                              encryption.
     -p, --bzip2              Use bzip2 to compress files before 
                              encryption.
     --flush                  Immediately flush the output
     -l, --doublecheck        Double check passwords.
     -u, --unlink             Unlink the input file after encryption 
                              or decryption.
     --nodelete               Do not delete the output file if 
                              decryption failed.
     -t, --time               Prints timing information.
     -F, --force              Forces output to stdout.
     --echo                   Echo asterisks when entering the 
                              password.
     -r, --random             Use real random data (if your system 
                              supports it).
     --list                   Prints a list of the supported 
                              algorithms and modes.
     --list-keymodes          Prints a list of the supported key 
                              modes.
     --list-hash              Prints a list of the supported hash 
                              algorithms.
     -V, --verbose            More information is displayed.
     -q, --quiet              Suppress some non critical warnings.
     --help                   Prints this help
     -v, --version            Prints the version number
     -L, --license            Displays license information.