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First, navigate to the 7zip download page and choose the version you would like to use.
After clicking download, you may receive the following prompt. Choose "Run".
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Next, the installation wizard will open. Follow the prompts to install 7zip.
Once the software is installed, open your documents folder and navigate to the document you would like to encrypt. Here, the document is "Creating a Zip File." Right click on the filename and scroll down to the 7zip tab. Mouse over it to open the options and click "Add to Archive."
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You can now open your email and attack the zip file. Make sure to communicate the password to the recipient by a method other than email.