當商業檔案如 EDI (850,860,810...) 在 FTP 協定中傳輸時，若被別人截取，那資料就會外洩。若能在傳輸前先加密，到客戶端時再作解密，這就保險多了。檔案加解密的軟體很，GnuPG (GPG) 是一套完全免費的軟體( GnuPG is the GNU project's complete and free implementation of the OpenPGP standard as defined by RFC4880 . )，也有在實務的商務中使用，安全性很高值得一用。
GPG, like PGP (Pretty Good Privacy), uses a key pair. This means that when you generate a key, you will create a public copy as well as private copy. The private copy is your copy used to decrypt an incoming file as well sign an outgoing file (but for our purposes, we are only using it to decrypt). The public key is the key you give to the public, which is used to encrypt the files coming to you. First we will create your own key.
These keys are stored in key rings. For GPG, they are stored in the directory that the GPG files were copied into. They are both named with a .GPG extension, and are called pubring.GPG and secring.GPG (to denote the public key ring and the private key ring, respectively).