for NeXTStep



WHY WOULD ANYONE WANT TO ATTACK YOUR COMPUTERS?

How about:

-financial fraud
-theft of resources
-industrial espionage
-wanton vandalism or `showoffs'
-malicious attacks by disgruntled employees
-illicit eavesdropping for financial or political gain

computerActive Inc.'s Entrust for NeXTStep provided your organization with a set of tools to manage the security and integrity of information throughout your enterprise. It addressed four key areas:

Data Privacy:
The contents of a protected file could only be viewed by the person who protected it and by the people who have been authorized by that person to do so.

Public Key Encryption:
Encryption was used to protect information stored electronically or being transferred between any users throughout an organization, and between different organizations inluding through mail systems through the INTERNET.

Data Origin Authentication:
You could check the digital signature of the person who signed the file to ensure the file really came from the person you think it did.

Data Integrity:
You could be sure the file had not been altered since it was signed. A valid digital signature that accompanied the file was the guarantee.

Automated Key Management:
It was easy for users to encrypt and sign files for others. The concept of keys was transparent to users, but was of utmost importance to guarantee the privacy and integrity of sensitive data.

User keys could have a limited validity period. When this time period expired Entrust automatically updated all users' keys with new ones without the users being aware that this update had occurred.



Product Features:

Graphical User Interfaces:
It was simple to use, quick to learn, an included online help.

High Speed Cryptographic Software:
On an Intel486 running, the encryption software was fast enough to be practical for encrypting all the files in a user's directories.

Encryption for Groups:
Encrypt a file for multiple recipients in one operation, without the overhead of creating separate encrypted copies for each recipient.

Choice of Encryption Algorithms:
Entrust supported the best available public key encryption algorithms and emerging standards, including RSA, DES and others.

All file types:
Entrust handled any file, from any application, without restriction. You could secure text, forms, images, even multiple files, with a single operation.

Key Security:
The cryptographic keys were created by the customer, therefore, were not accessible to any external agency.

ASCII Encoding Option:
It could make encrypted files compatible with all electronic transfer methods, including ASCII-only electronic mail systems.

Written by computerActive Inc using licensed toolkits from Entrust Corporation.
(Entrust is a trademark of Entrust Corporation)


Using NEXTSTEP Entrust

Launch the Application

Select a file, drag and drop it onto the Entrust Icon on your Dock. In this example we will use Shakespeare/Hamlet/1.2.

If the Entrust application is not already running it will be launched and you will be asked for a password.

Note that this password is not the password and account you use for logging into the NEXTSTEP computer. This is an entirely independent account used only for encrypting and/or signing documents or folders. Whatever holes may or may not exist within the NEXTSTEP accounts and security system are eliminated here.

Select the intended recipients

Once you enter your Entrust password you will be presented with a Select Recipients panel inviting you to select one or many recipients.

This is where Entrust starts to differentiate itself. The list of names you see in the Selection List with their public keys is from a corporate wide X.500 database of public keys.

This database holds all the public keys approved and verified by trusted individuals in the organization. It records not only the person's public key but also the certifying authority.

An X.500 database is capable of managing thousands of users, so we provide you with the ability to create groups or mail lists. With a single click of a mouse you could select a group of ten people who are intended readers of this soon-to-be-encrypted and signed file.

Encrypt the file or folder

Once you have all the desired individuals and groups listed in the Selected Recipients window, press the Encrypt button.

The Select Recipients panel will disappear and be replaced by a Process Status Panel. This gives a running report on the progress of the encryption.

For the file Shakespeare/Hamlet/1.2 which is 15494 bytes long and 9 printed pages long, it takes less than 3 seconds to complete the job for six recipients and write it to the disk on a three year old NeXTstation Turbo. Experts in the field will be picki ng themselves off the floor about now. This as at least ten times faster than traditional speeds given the same file sizes and hardware.

Note that there are two pie charts. One to show the progress of the individual file being encrypted and the other to show the progress of the whole folder being encrypted if that is what you wanted.

Note the resultant file

For output you have choices. In the above example we chose to have the original file hard deleted from the disk and replaced with the encrypted file. This is appropriate if you wish to secure a file in your home directory.

However if your intent is to keep the file "in the clear" on your home directory but wish to have a secured copy to send over the internet , then you would go to the preferences panel and deselect the "Delete after encrypting" check box.

Note that in this panel there is an Encrypt operations section with choices of encryption algorithms. Today there are two DES and CAST. In the future there will be more.

Note also that there are check boxes for Encrypt, Sign and My eyes only. You might want to sign a document but not encrypt it. This would allow anyone to read the file with absolute confidence that you signed it and that it has not been changed after you signed it. My eyes only is a short cut which encrypts files for yourself without the Selected Recipients panel popping up.

As NEXTSTEP users we sometimes forget that there are still people out there who's e-mail systems can only handle ASClI. We provide an option in the Destination Files section for writing the files in ASCII. Normally you would want to keep them in binary form (tougher to break the encryption, faster to decrypt and the resultant files are smaller).

You now have an encrypted and signed file which can be left on the network server with confidence. If anyone manages to defeat the Unix file security systems and illegitimately grab a copy they will not be able to decipher the contents. The same can be s aid for sending it across the Internet.

Decrypt the file

Encrypted files have a file name extension .ent . Select the file you wish to decrypt in the file viewer and double click it. If the Entrust application is still running it will decrypt the file. If not, then the double click will launch the application , ask for your password and then decrypt the file. In our example of Shakespeare/Hamlet/1.2 the file was decrypted in less than 2 seconds and then an appropriate application was launched to view the file. In this example it was Edit.

You have decrypted a file.

The above panel tells you where it put the resultant file and in the Files section it lists the decrypted files and their status. Note two icons beside the file name, one looks like an open padlock, the other looks like a pen. If you click on the Signature button a new panel will pop up.

If you see this panel you know that the file was not corrupted along the way and that it was signed by Jill Hennessy and that HASC-ELM certifies that this was really Jill's valid public key. Note if even a single character, comma or space was changed you would not see this panel. The decryption process would abort and you would be told that things are not right.

Prove it to yourself. Encrypt a file. Open it with edit, go to the middle of the jumble of characters and change something, save the file. Now try to decrypt it. It will know. Make sure you do this on a copy of the encrypted file.

Note that this encryption/signature process is independent of the application used to create the source file. It is independent of operating system. That file could be sitting on a Novell server, or a Digital NFS server. It doesn't matter, if your NEXTSTEP computer can see the file you can encrypt and sign it. The process is independent of the transport mechanism. You may have gotten it from a server or from a floppy or from an Internet e-mail. It doesn't matter to the system. Any file you encrypt and/o r sign can be decrypted on Macintoshes, Windows, Sun's and HP workstations.

Back to the Preferences Panel

In the Decrypt Operations section you have the option of writing the decrypted file to disk with the same file name or to keep the information in memory and launch an application.

Under the Decrypt Options you can choose to leave the encrypted file on the disk and write the decrypted file to the hard disk or you can cause the encrypted file to be hard deleted upon decryption.

The Destination Files option asks if it should overwrite existing files if they have the same file name.

In the General Options section you can set a time-out for automatic log off of Entrust after a specified idle time. Note that this is again separate from the general system account and will not log you out of your NEXTSTEP system.

The remaining fields have to do with you taking your NEXTSTEP portable on the road. It is possible for you to download a database of valid public keys to take with you. You are exposed, should one of those keys be declared invalid while you are away you won't know about it until you reconnect to the network. The risk is probably acceptable for short periods of time. It's certainly better than telling the world to invalidate a lost credit card number.

Should you for any reason feel that your key pair has been compromised, you have only to notify your Certifying Authority. Your old public key will be invalidated. A new key pair will be issued. Within moments everyone on the net will be using the new pu blic key. Users look you up know anything has changed.

This capability allows your organization to effect sophisticated policies like automatic expiration of key pairs when students go back to school or when employees leave the company. After invalidation of their key pairs it is still possible to access the work they left behind through an auditable mechanism. You may automate the expiration of keys of all employees at regular intervals without the users knowing or caring. Their private signature password remains intact.

Integration within NEXTSTEP

From any application select a portion of a file. Go to the Browser Services menu. Select Entrust/Selection and the selected information will be encrypted and written to a file in a directory specified by you.



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