ENCRYPT(3) Linux Programmer's Manual ENCRYPT(3)

NAME
       encrypt, setkey, encryptr, setkeyr - encrypt 64-bit messages

SYNOPSIS
       #define XOPENSOURCE       /* See featuretestmacros(7) */
       #include 

       void encrypt(char block[64], int edflag);

       #define XOPENSOURCE       /* See featuretestmacros(7) */
       #include 

       void setkey(const char *key);

       #define GNUSOURCE         /* See featuretestmacros(7) */
       #include 

       void setkeyr(const char *key, struct cryptdata *data);
       void encryptr(char *block, int edflag, struct cryptdata *data);

       Each of these requires linking with -lcrypt.

DESCRIPTION
       These  functions  encrypt  and  decrypt  64-bit messages.  The setkey()
       function sets the key used by encrypt().  The key argument used here is
       an  array  of  64 bytes, each of which has numerical value 1 or 0.  The
       bytes key[n] where n=8*i-1 are  ignored,  so  that  the  effective  key
       length is 56 bits.

       The  encrypt()  function modifies the passed buffer, encoding if edflag
       is 0, and decoding if 1 is being passed.  Like the key  argument,  also
       block  is  a  bit  vector  representation  of  the actual value that is
       encoded.  The result is returned in that same vector.

       These two functions are not reentrant, that is, the key data is kept in
       static storage.  The functions setkeyr() and encryptr() are the reen‐
       trant versions.  They use the following structure to hold the key data:

           struct cryptdata {
               char     keysched[16 * 8];
               char     sb0[32768];
               char     sb1[32768];
               char     sb2[32768];
               char     sb3[32768];
               char     crypt3buf[14];
               char     currentsalt[2];
               long int currentsaltbits;
               int      direction;
               int      initialized;
           };

       Before calling setkeyr() set data->initialized to zero.

RETURN VALUE
       These functions do not return any value.

ERRORS
       Set errno to zero before calling the above functions.  On  success,  it
       is unchanged.

       ENOSYS The  function  is  not provided.  (For example because of former
              USA export restrictions.)

ATTRIBUTES
       For  an  explanation  of  the  terms  used   in   this   section,   see
       attributes(7).

       ┌────────────────────────┬───────────────┬──────────────────────┐
       │Interface               │ Attribute     │ Value                │
       ├────────────────────────┼───────────────┼──────────────────────┤
       │encrypt(), setkey()     │ Thread safety │ MT-Unsafe race:crypt │
       ├────────────────────────┼───────────────┼──────────────────────┤
       │encryptr(), setkeyr() │ Thread safety │ MT-Safe              │
       └────────────────────────┴───────────────┴──────────────────────┘
CONFORMING TO
       The  functions  encrypt()  and  setkey()  conform  to  SVr4, SUSv2, and
       POSIX.1-2001.  The functions encryptr() and setkeyr() are GNU  exten‐
       sions.

NOTES
       In glibc 2.2 these functions use the DES algorithm.

EXAMPLE
       You  need to link with libcrypt to compile this example with glibc.  To
       do useful work the key[] and txt[] arrays must be filled with a  useful
       bit pattern.

       #define XOPENSOURCE
       #include 
       #include 

       int
       main(void)
       {
           char key[64];      /* bit pattern for key */
           char txt[64];      /* bit pattern for messages */

           setkey(key);
           encrypt(txt, 0);   /* encode */
           encrypt(txt, 1);   /* decode */
       }

SEE ALSO
       cbccrypt(3), crypt(3), ecbcrypt(3),

COLOPHON
       This  page  is  part of release 3.53 of the Linux man-pages project.  A
       description of the project, and information about reporting  bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.



                                  2013-07-22                        ENCRYPT(3)