crypt.h File Reference

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Macros
#define	CRC32(c, b)   ((*(pcrc_32_tab+(((int)(c) ^ (b)) & 0xff))) ^ ((c) >> 8))
#define	zdecode(pkeys, pcrc_32_tab, c)    (update_keys(pkeys,pcrc_32_tab,c ^= decrypt_byte(pkeys,pcrc_32_tab)))
#define	zencode(pkeys, pcrc_32_tab, c, t)    (t=decrypt_byte(pkeys,pcrc_32_tab), update_keys(pkeys,pcrc_32_tab,c), (Byte)t^(c))

Functions
static int	decrypt_byte (unsigned long *pkeys, const z_crc_t *pcrc_32_tab)
static int	update_keys (unsigned long *pkeys, const z_crc_t *pcrc_32_tab, int c)
static void	init_keys (const char *passwd, unsigned long *pkeys, const z_crc_t *pcrc_32_tab)

Macro Definition Documentation

CRC32

#define CRC32	(		c,
			b
	)		((*(pcrc_32_tab+(((int)(c) ^ (b)) & 0xff))) ^ ((c) >> 8))

Definition at line 30 of file crypt.h.

zdecode

#define zdecode	(		pkeys,
			pcrc_32_tab,
			c
	)		(update_keys(pkeys,pcrc_32_tab,c ^= decrypt_byte(pkeys,pcrc_32_tab)))

Definition at line 77 of file crypt.h.

zencode

#define zencode	(		pkeys,
			pcrc_32_tab,
			c,
			t
	)		(t=decrypt_byte(pkeys,pcrc_32_tab), update_keys(pkeys,pcrc_32_tab,c), (Byte)t^(c))

Definition at line 80 of file crypt.h.

Function Documentation

decrypt_byte()

static int decrypt_byte ( unsigned long *  pkeys, const z_crc_t *  pcrc_32_tab  )

static

Definition at line 35 of file crypt.h.

{
    unsigned temp;  /* POTENTIAL BUG:  temp*(temp^1) may overflow in an
                     * unpredictable manner on 16-bit systems; not a problem
                     * with any known compiler so far, though */
 
    (void)pcrc_32_tab;
    temp = ((unsigned)(*(pkeys+2)) & 0xffff) | 2;
    return (int)(((temp * (temp ^ 1)) >> 8) & 0xff);
}

init_keys()

static void init_keys ( const char *  passwd, unsigned long *  pkeys, const z_crc_t *  pcrc_32_tab  )

static

Definition at line 66 of file crypt.h.

{
    *(pkeys+0) = 305419896L;
    *(pkeys+1) = 591751049L;
    *(pkeys+2) = 878082192L;
    while (*passwd != '\0') {
        update_keys(pkeys,pcrc_32_tab,(int)*passwd);
        passwd++;
    }
}

update_keys()

static int update_keys ( unsigned long *  pkeys, const z_crc_t *  pcrc_32_tab, int  c  )

static

Definition at line 49 of file crypt.h.

{
    (*(pkeys+0)) = CRC32((*(pkeys+0)), c);
    (*(pkeys+1)) += (*(pkeys+0)) & 0xff;
    (*(pkeys+1)) = (*(pkeys+1)) * 134775813L + 1;
    {
      register int keyshift = (int)((*(pkeys+1)) >> 24);
      (*(pkeys+2)) = CRC32((*(pkeys+2)), keyshift);
    }
    return c;
}

Referenced by init_keys().