
ATTACH2CLOUD | How to secure MS Outlook attached files
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Some of your MS Outlook attachments are strictly confidential?
You want to secure them and encrypt them to prevent unauthorized third parties from accessing their content.
Tutorial:
In MS Outlook, create a new email then click on the Paperclip button / Browse this PC…:
Select the file(s) to attach to your MS Outlook email:
To secure your MS Outlook attached file, tick the Password checkbox:
Enter your password and click on Insert:
Confirm your password and validate:
Attach2Cloud has secured and encrypted your attached file using your password:
If you or the recipients of your email having Attach2Cloud installed attempt to open this secured attachment by double-clicking on its icon in your MS Outlook email, Attach2Cloud will ask you for the password that was used to secure it before opening it in its associated application (Microsoft Word in our example):
If the recipients of your email, not having Attach2Cloud installed or using another email client than MS Outlook, attempt to open your secured attached file by double-clicking its icon in your email, Windows Explorer will ask them for the password that was used to secure it before allowing them to access the file:
How to secure MS Outlook attached files
Questions & Answers
Question #1
Which is the encryption method used?
- A simple and effective principle:
Locking your MS Outlook attachments and encrypting them is based on a password known only to you and the people to whom you want to provide access to the contents of your attachments.
You can thus restrict the access to the content of your confidential attached files to those people to whom you have communicated (preferably by another channel, such as SMS or phone) the password used to lock and encrypt them. - Using a standard, public encryption format:
By using this standard, public encryption Zip format, recipients of your secured Outlook attachments do not need Attach2Cloud or any third-party software to decrypt them.
For example, in Windows, the Windows File Explorer will automatically display a dialog asking for the password used to secure the encrypted Zip file when an attempt is made to open it.
The fact that this format is public ensures that there are no secret backdoors that would allow malicious third parties not knowing the password to access the contents of your encrypted attachments. - Extremely strong protection:
Only a brute force attack (a program attempting to open a password protected file by testing different passwords based on password dictionaries or automatically composed passwords) can have a chance to break a password protected Zip file. A reasonably long password with a few special characters offers extremely strong protection in this matter: a brute force attack program running on a high-end PC would need, depending on the diversity of characters composing the password, from a few tens of thousands to a few hundred of thousand years to have a chance of finding a 12-character password with special characters, upper and lower case. Check here:
https://www.security.org/how-secure-is-my-password/
Even with a super-computer with the power of 1,000 PCs, it would still take hundreds of years to crack your password.
If this level of security seems insufficient to you, you can easily strengthen it by using a longer password.
With one more character, i.e. a 13-character password with special characters, upper and lower case, it will take a high-end PC millions of years to crack your password. Enough to discourage the most virulent hackers.
Question #2
How are the password rules set?
- minimum length of the password
- minimum number of letters
- minimum number of lower case letters
- minimum number of upper case letters
- minimum number of numbers
- minimum number of special characters
are defined via Attach2Cloud settings.
These settings can be locked (made not editable by users) or unlocked.
In the Attach2Cloud ribbon displayed in the main window of MS Outlook, a click on the Options button and then on the Attached file Password & Encryption menu displays this window allowing the user to view (or modify if he/she is allowed to) the rules applying to passwords:
Question #3
How to secure multiple attached files in one operation?
. There are two ways to secure multiple MS Outlook attached files in a single operation:
The first one is to simply select several files in the Paperclip button file selection dialog and to check the password checkbox as per the above tutorial.
The second way is to attach one or more folders using the Attach Folders button added by Attach2Cloud to the MS Outlook email form Message tab:
Clicking this button displays a dialog enabling you to select one or more folders.
This dialog includes a Password checkbox:
Simply tick it to secure the selected folders (and their sub-folders if any). After asking you for a password, Attach2Cloud will attach the selected folders to your email under the form of a single password-protected + encrypted Zip file.

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