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Tools and support

IT Support / Storage

Encrypting files

How to encrypt and password protect your information, i.e. files or documents, for secure storage or sharing via email.

Secure file sharing via email

  • When sending files via email you can compress the data with 7-Zip to restrict the use of bandwidth 

Or

  • you can password-protect and encrypt data for secure sharing or storage.

When should I encrypt files?

Upon storing and sending of data files with sensitive information in open places such as the Internet (email), memory sticks, memory cards, DVDs and the like.

  • Research data and other information containing sensitive personal data should always be encrypted when sent by email.

Contact User support IT if it is inconvenient for you to encrypt files as separate attachments in the form of zip files, and you wish to rather directly encrypt the contents of the emails, for example upon  longer email exchanges that deal with sensitive information.

See also encryption of storage media.

Compression and encryption using 7-Zip

Download the programme 7-Zip

1. Compress files

  1. Right-click the file you want to encrypt.
  2. Select 7-zip - in the left menu.
  3. Then select: Add to archive - in the right menu

2. Add to archive

Select the compression format: (see screenshot below)

  • ZIP

3. Encryption method

Always select the encryption method:

  • AES-256

4. Password

  • Create a secure password consisting of at least eight - 8 - characters.
  • Use both uppercase and lowercase letters, numbers and special characters.
  • NB! Never send your password as open text in an email. The password must be agreed upon with the recipient and should ideally be delivered in person, preferably orally, for example by phone. Be careful if you choose to send your password via SMS.

5. Complete compression and password protection

  • To complete compression and password protection of the file, click: OK.

6. Zip file with the same name

  • You will get an archive file in the same folder with the “.zip”-ending.
  • The ZIP file will be encrypted with the password you chose.

7. Open and test the encrypted ZIP file

  • Check that the file can be opened using the password you chose.
  • If the password opens the document, the ZIP file is encrypted and ready to be stored or sent via email.

Tips and advice

  • If you send the password by SMS, tell the recipient to delete the message before, or immediately after, the encrypted file is received. This is because SMSs are stored "openly" on the same mobile device as the recipient’s mailbox.
  • File names must not contain sensitive information. The file names inside the packaged zip file are always visible.
  • Do not not indiscriminately open encrypted files on computers that can be used by unauthorised persons.
  • When you open files, a temporary copy is created under a temporary directory on the C drive. The track to a temporary file directory may for instance be: C:\Users\<user>\AppData\Local\Temp\......
    7-zip will normally erase this, but since the file now has been stored as an unencrypted file on the local disk, it can be restored.

How to extract the zip file

Some applications are zipped to make large files smaller for faster downloads.

A Zip file must be unzipped on your computer before you can use the program.

Guide on how to extract Zip files (windows.microsoft.com)

Video tutorial on how to zip/ unzip files (windows.microsoft.com)

See also

Encrypting email and attachments (support.office.com)

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