Zip a File or Directory with a Password
Here is how encrypt/decrypt files and directories with a password using zip/unzip.
Note that using GPG and .tar.gz archives may offer a better alternative.
Zip and encrypt one or more files
zip --encrypt <output-file>.zip <input-file-1> <input-file-2> ...
Zip and encrypt a directory (recursive)
zip -r --encrypt <output-file>.zip <input-directory>
Decrypt a zip file
unzip <input-file>.zip