Encryption of confidential attachments

• Open 7-zip.
  

• Find the file to be encrypted by selecting Open in the File menu.
  

• Select the file to be encrypted and start encryption by clicking Add.
• The name of the package is selected in the Archive section (1). The name must be such that no confidential information is conveyed to outsiders.
• The default value of the program, 7z, should be selected in the Archive format section. 7z is opened only with the 7-zip program, so you must be sure that the receiver uses said program. Alternatively, the package can be made into a spontaneously opening exe file (Options > Create SFX archive). All e-mail services do not let executable files, such as exe, through. It is advisable to give the file another name (e.g. file.exe > file.sfx) and instruct the receiver to rename the file back to (file.sfx > file.exe).
• The Password (3) must be very difficult or impossible to guess.
  • A minimum requirement is that the word contains at least 8 characters and has upper and lower case letters, numbers and special characters. The recommendation is a password at least 16 characters long, as deciphering passwords with a computer is very easy.
  • An encrypted file cannot be opened by anything other than the password, so it must be secured.
• Encryption method (4) AES-256
• File names must also be encrypted (5: Encrypt file names)
  
  

• By clicking OK, the program will save the encrypted file in the same folder with the file extension .7z.
  

The encrypted file can now be sent with e-mail. Send the password needed to open the file to the receiver through a communications channel other than the file itself. For example, a text message or telephone can be used for that purpose. Do not send the password in another e-mail.

Person A must send confidential electronic materials to person B.

1. A makes sure that B has access rights to the materials in question.
2. A agrees with B to send the materials as a 7z package via e-mail and the password in a text message.
3. A compresses and encrypts the data materials with the 7-zip program and sends them to B via e-mail.
4. A sends the password to B in a text message.

If you receive an encrypted file via e-mail, follow these steps:

• Save the attached file on your computer.
• Right-click the file.
• Select 7-Zip > Extract here on the menu.
  
  
• Enter your password.
• Click OK.
  
  

The file is now decrypted on your computer, in the same folder with the encrypted attachment.