encrypt functions problems

[Dr. A.Bykat]

Tried to use the encrypt C Library function (under SunOS 4.X, 4/60) and
run into the following problems:

1) setkey() does not work; it produces

     ld: Undefined symbol   _setkey

2) without setkey() the encrypt(data,0) crypts the data, while
   encrypt(data,1) produces the original data only if both functions are
   called within the same program.  However, if program1 invokes
   encrypt(data,0) and program2 feeds the encrypted data to encrypt(data,1)
   gibberish results.

Is this a known problem? Is there a way to overcome it?