Guidance for Sending and Receiving Secure
E-mails with Encrypted Document Attachments
7-Zip Encryption Software
CONTENTS
Introduction
Encrypting a Document Using WinZip
Opening a WinZipped Encrypted Document with 7-Zip
Introduction
To send documents securely by e-mail, you will need to encrypt the documents and
protect them with a password before sending them. By doing this, it will ensure that
if the e-mail was intercepted or delivered to the wrong address, the document cannot
be opened by anyone who does not know the password, therefore, the information
contained within it is safe.
There is a free piece of software available to anyone which can encrypt documents
and open encrypted documents. This software is called 7-Zip and can be
downloaded and installed by clicking on the link to this web page or by copying the
web address and pasting it into your web browser.
http://www.7-zip.org/
Once you have downloaded 7-Zip and installed this on your machine, you can follow
the instructions below which will guide you how to encrypt documents so that you
can send them securely by e-mail and also how to open any encrypted documents
that you receive.
Encrypting a Document Using 7-Zip
(1) Go to the Start button and select Windows Explorer.
QUICK TIP – You can also open Windows Explorer by holding down the Microsoft
Windows button and pressing “E”.
+
(2) Locate the document you want to encrypt and right click on it. Go to 7-Zip and
from the list select Add to archive….
The following window will now open:
(3) If the file name contains personal information, you may wish to change this in the
Archive field. This is because the file name can still be seen after you have
encrypted the document.
2
4 Add to Archive
1) Change the Archive Format to “Zip”
2) Enter (and re-enter) a Password.
Note: Government guidance suggests that any encrypted information should be
protected by a 14 character “strong” password. Strong passwords are one which
consist of a variety of uppercase letter, lowercase letters, special characters and
numbers. (see Password Guidance for Encryption below)
(5) Now click OK and an encrypted version of the document will be created which
cannot be opened without the password:
You can now attach this encrypted document to an e-mail to send to your recipient.
You will obviously need to contact your recipient to let them know the password and
it is advised that you do not do this in the same e-mail in case the e-mail is
intercepted or delivered to the wrong address.
Password Guidance - Encryption
When sending an encrypted document by e-mail, you are required to protect the
document with a "strong" password.
In line with government requirements the password you create for encrypting
documents to email must be at least 14 characters long and must contain 3 of the
following 4 criteria:




Uppercase letters
Lower case letters
Numbers
Special characters (for example, $ % &)
You must also ensure that you do not re-use the same password after a 30 day
period.
Telling an e-mail recipient your password
When sharing an encrypted document with someone, for them to open it, they will
need to know the password which protects it.
You can do this by telephone, however, if you e-mail the same person on a regular
basis, to save you from calling them every time you send them an e-mail, you could
try agreeing a password "structure" with them. For example:
You could agree to create part of the password from the date of you sending the
email for example:


G&mn$X01072010
G&mn$X01July2010
As you can see, the last 8 characters of the password would be if you sent an e-mail
on 01 July 2010.
By using this method, the password you will use will automatically change on a daily
basis.
Password Confidentiality





If you write your password down, never leave it where it can be seen by
anyone else (make sure you lock them away).
Never use the same password for different e-mail recipients
Never use part of your computer user name in a password
Never use the same password as what you use to access Setting’s systems.
Never use the same passwords inside of work as you do outside of work. If a
password you use is known to someone else, there is nothing stopping them
accessing your personal information, for example, on line banking etc.
Opening a WinZipped encrypted document with 7-Zip
Once you have received an e-mail with a WinZipped encrypted document attached,
you can follow the instructions below to open it:
(1) Double click the attachment in the email and you will receive the following
message:
(2) Click on Save
(3) Select a location to save the document.
(4) Go to the Start button and select Windows Explorer.
QUICK TIP – You can also open Windows Explorer by holding down the Microsoft
Windows button and pressing “E”.
+
(5) Browse for the file in the location you saved it:
(6) Right Click on the file and select 7-Zip and Open Archive
PLEASE NOTE – If you do not have the 7-Zip option, please go to step
(9)
(7) The following window should now open.
(8) Double-click the file and you will be prompted for a password, enter the
password and click OK and the document should open.
The file should now open.
TIP – If you need to open the file again in the future, we would advise that you save
a copy of the open document to prevent inputting the password every time you wish
to open it.
(9) If you do not have the 7-Zip option, then you will need to complete the
instructions below. You will only need to do this once as for future encrypted
documents, the computer will recognise which programme you use to open it.
(10) Right Click the file and select Open With and Choose Program…
(11) Check the box “Always use the selected programme to open this kind of
file”, then Browse
(12) Click on the 7-Zip folder
(13) Click on 7zFM
(14) Double click on 7-Zip File Manager and return to step (7)
How to Encrypt a Document (or folder) to E-mail Securely with
WinZip
1- Open Windows Explorer by clicking the Start button and selecting Windows
Explorer.
QUICK TIP – You can also open Windows Explorer by holding down the Microsoft
Windows button and pressing “E”.
+
2- Browse the folders to find the document (or folder) you wish to send by e-mail and
make sure the file name does not contain sensitive information.
Right click on the document (or folder) and select Send To and Compressed
(Zipped) Folder
3- Select Yes to the following prompt to create a “zipped” version of the document
(or folder).
4- Double click the “zipped” version of the document (or folder) which has been
created
5 – Click Yes to the following message:
6- Click once on the document (or folder) once to highlight it and then click Encrypt.
7- Click OK to the following message:
QUICK TIP – to prevent this message appearing in future when encrypting a
document (or folder), click the box “Do not display this dialogue box in the
future”
8 – You will now be asked to create a password:
Enter and re-enter a “strong” password. For guidance on how to create a strong
password, please see previous Password Guidance – Encryption notes.
Select the 256-Bit AES encryption option and click OK
9 – Now open a new e-mail message and click Insert and File:
10 – Browse for the “zipped” encrypted document (or folder) and double click it to
attach it to the e-mail:
You can now edit your e-mail to send.
11- For the recipient to open the file, they will need to know the password you have
used to protect each document. Do not do this by sending a further e-mail, follow
the advice given previously in Password Guidance notes.
Adding Additional Documents
To add further documents:
Repeat steps 1-10 for each document (or folder).
What can I do to Encrypt Multiple Documents?
As well as encrypting documents, you can actually encrypt a folder which will encrypt
all of the files contained in it.
If you are sending multiple files in an e-mail, you can create a folder, copy all the files
you want to send into the folder then follow steps 1-10 to encrypt the folder: