isencrypt(3G)                                                 isencrypt(3G)


   NAME
         isencrypt - determine whether a character buffer is encrypted

   SYNOPSIS
         cc [flag ...] file ...  -lgen [library ...]

         #include <libgen.h>

         int isencrypt (const char *fbuf, sizet ninbuf);

   DESCRIPTION
         isencrypt uses heuristics to determine whether a buffer of characters
         is encrypted.  It requires two arguments: a pointer to an array of
         characters and the number of characters in the buffer.

         isencrypt assumes that the file is not encrypted if all the
         characters in the first block are ASCII characters.  If there are
         non-ASCII characters in the first ninbuf characters, isencrypt
         assumes that the buffer is encrypted if the setlocale LCCTYPE
         category is set to C or ascii.

         If the LCCTYPE category is set to a value other than C or ascii,
         then isencrypt uses a combination of heuristics to determine if the
         buffer is encrypted.  If ninbuf has at least 64 characters, a chi-
         square test is used to determine if the bytes in the buffer have a
         uniform distribution; and isencrypt assumes the buffer is encrypted
         if it does.  If the buffer has less than 64 characters, a check is
         made for null characters and a terminating new-line to determine
         whether the buffer is encrypted.

   DIAGNOSTICS
         If the buffer is encrypted, 1 is returned; otherwise zero is
         returned.

   SEE ALSO
         setlocale(3C).

















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