Step 1: Click the "File" tab -> "Info" -> "Protect Document" -> "Encrypt with Password"
Step 2: Type in
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a password and click "OK".
Note: Tutorials on how to choose a good password is located at https://docs.rice.edu/confluence/display/ITTUT/Passwords
Step 3: Reenter the password and click "OK".
Step 4: After choosing a password you should see that your document is encrypted.
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