encrypt - phpMan

ENCRYPT(3)                  Cryptographic Functions                 ENCRYPT(3)



NAME
       encrypt, setkey, encrypt_r, setkey_r - encrypt 64-bit messages

SYNOPSIS
       #define _XOPEN_SOURCE
       #include <unistd.h>

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

       #define _XOPEN_SOURCE
       #include <stdlib.h>

       void setkey(const char *key);

       #define _GNU_SOURCE
       #include <crypt.h>

       void setkey_r (const char *key, struct crypt_data *data);
       void encrypt_r (char *block, int edflag, struct crypt_data *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 parameter 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 parameter 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 setkey_r() and encrypt_r() are the reentrant versions.  They
       use the following structure to hold the key data:
              struct crypt_data {
                    char keysched[16 * 8];
                    char sb0[32768];
                    char sb1[32768];
                    char sb2[32768];
                    char sb3[32768];
                    char crypt_3_buf[14];
                    char current_salt[2];
                    long int current_saltbits;
                    int  direction, initialized;
              };
       Before calling setkey_r() 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.)

EXAMPLE
       You need to link with libcrypt to compile this example with glibc2.2.  To do useful
       work the key[] and txt[] array must be filled with a useful bit pattern. Note  that
       the  <crypt.h>  header  unconditionally  gives  the  prototypes  for  setkey()  and
       encrypt().

       #include <crypt.h>

       main() {
         char key[64];      /* bit pattern for key */
         char txt[64];      /* bit pattern for messages */
         setkey(key);
         encrypt(txt, 0);   /* encode */
         encrypt(txt, 1);   /* decode */
       }

NOTE
       In glibc2.2 these functions use the DES algorithm.

CONFORMING TO
       The functions encrypt() and setkey() conform to SVID, SUSv2, and POSIX 1003.1-2001.
       The functions encrypt_r() and setkey_r() are GNU extensions.

SEE ALSO
       cbc_crypt(3), crypt(3), ecb_crypt(3), fcrypt(3)



glibc2                            2003-04-04                        ENCRYPT(3)

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