Exchanging Files Securely

What's the best way to securely exchange files with our customers and outside contractors? We've tried secure FTP, but not everyone has the right software or knows how to use it. We'd prefer some encryption options that use interfaces the typical user would be more comfortable with yet that are secure.

I have yet to find the perfect file-encryption utility that combines ease of use and an excellent encryption implementation. That said, the encryption features in Microsoft Office Word 2003 and Microsoft Office Excel 2003 or in WinZip Computing's WinZip might be sufficient for your needs if you follow a few basic rules.

In Word 2003 and Excel 2003, you can specify a password that will then be required to open the document. With the document open, select Tools, Options, Security. Click Advanced, and select RC4, Microsoft Strong Cryptographic Provider, choose a key length of 128 (bits), and select the Encrypt document properties option, as Figure 2 shows. Make sure you specify a password that has at least eight random characters, but to get close to the entropy of a truly random key, 20 characters are much better. . . .