Knowing the Encryption Guidelines

In general, there are no differences between using the encrypted models and using regular models. However, you must test your subcircuits before encryption . You will not be able to see what has gone wrong after encryption because of the protection offered by Star-Hspice.

Use any legal Star-Hspice statement inside your subcircuits to be encrypted. Refer to .SUBCKT or .MACRO Statement for further information on subcircuit construction. You must take care when structuring your libraries. If your library scheme requires that you change the name of a subcircuit, you must encrypt that circuit again.

Placement of the .PROTECT and .UNPROTECT statements allows your customers to see portions of your subcircuits. If you protect only device model statements in your subcircuits, your users can set device sizes or substitute different subcircuits for lead frames, protection circuits, and so on. This requires your users to know the circuits, but it reduces the library management overhead for everyone.

NOTE: If you are running any version of the encryptor prior to Star-Hspice Release H93A.03, there is a bug that prevents Star-Hspice from correctly decrypting a subcircuit if that subcircuit contains any semicolon (;) characters, even in comments.

In the following example, the subcircuit badsemi.dat is encrypted into badsemi.inc.

To solve this problem, remove the semicolon from badsemi.dat and encrypt the file again.

Prior to the 2001.2 version, Metaencrypt cannot encrypt files with lines longer than 80 characters. Metaencrypt version 2001.2 can encrypt files with lines longer than 80 characters but cannot correctly encrypt files with lines longer than 254 characters. Avant! strongly recommends that all files to be encrypted be limited to a 254-character line length and use version 2001.2 and above to encrypt any files with lines longer than 80 characters. Star-Hspice can recognize all correctly encrypted files.

You cannot gather the individually-encrypted files into a single file or include them directly in the Star-Hspice netlist. Place them in a separate directory pointed to by the .OPTION SEARCH = < dir > named < sub >. inc for correct decryption by Star-Hspice.