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Previous: 22.16 Copying Permissions with cpmod Chapter 22
File Security, Ownership, and Sharing
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22.17 Ways of Improving the Security of crypt

Files encrypted with crypt are exceedingly easy for a cryptographer to break. For several years, it has been possible for noncryptographers to break messages encrypted with crypt as well, thanks to a program developed in 1986 by Robert Baldwin at the MIT Laboratory for Computer Science. Baldwin's program, Crypt Breaker's Workbench (cbw), automatically decrypts text files encrypted with crypt within a matter of minutes.

cbw has been widely distributed; as a result, files encrypted with crypt should not be considered secure. (They weren't secure before cbw was distributed; fewer people simply had the technical skill necessary to break them.)

Although we recommend that you do not use crypt to encrypt files more than 1 k long. Nevertheless, you may have no other encryption system readily available to you. If this is the case, you are better off using crypt than nothing at all. You can also take a few simple precautions to decrease the chances that your encrypted files will be decrypted:

- SG, GS


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