This C-based tool utilizes several Linux facilities (and hence it is GNU-based) to ultimately serve as a tool for encrypting your contents (maybe, umm, from SysAdmins?) and decrypting them back. Since it has a CBC-MAC implemented as well, it has data integrity feature, i.e., if anyone tampers your encrypted data, the decryption will fail with an evident failure message.
Encryption is done using AES in CTR mode. MACing is done using AES in CBC mode.
NOTE: It is still possible to partially decrypt your data, however, there is a high possibility, there will only be a partial recovery. Hence, if the data is anything apart from text, don't expect to get it back. Well, that's how encryption was initially visioned.