gandalf- / qcrypt

Full featured commandline encryption with OpenSSL

qcrypt

Full featured command line encryption with OpenSSL

usage: qcrypt (-a|-e|-d) [-z|-t] target_name

• The -a switch signals auto mode, in which qcrypt detects whether to encrypt or decrypt the file based on the targets file extension. qcrypt defaults to encryption.
• The -e or -d switches to signal encryption or decryption.
• The -z and -t flags allow you to require qcrypt to use zip or tar respectively for compression. By default qcrypt uses which ever is available on the users system, preferring zip if both are present. During decryption and if present, the file extension overrides these flags.

Requires

• openssl
• zip or tar
• md5sum

qcrypt compresses the target directory or file and uses AES256 salted password encryption provided through openssl.

qcrypt uses the .zaes256 and .taes256 file extensions to denote its own archives. The existence or lack there of these extensions is what determines whether the argument is a target or archive, and which compression program to use.

qcrypt computes a checksum of the the target before compression and encryption to ensure that the archive has not been tampered with at rest. This checksum is then verified after successful decryption. It also maintains the date the archive was created to alert the user when last the archive was opened upon successful decryption. This information is kept inside the archive itself and is removed upon decryption and presentation to the user.

qcrypt has extensive error checking. It alerts the user if any part of the encryption or decryption process fails or is interrupted and attempts to clean up its working files. The original target or archive is preserved during encryption and decryption failure respectively so that another attempt can be made once the problem is remedied.

qcrypt supplies a warning if it detects re-encryption of an archive, however this action is not disallowed. Likewise, attempted decryption of an archive without a qcrypt file extension will produce a warning but is allowed. This allows the user to rename archives and remove the qcrypt file extension if so desired. Without the -z or -t flags to denote the compression program required, qcrypt will default to using zip on the archive when it is unable to detect the compression through the file extension.