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Create custom "loop count" system to determine how many times to hash a password when encrypting based on the datestamp.

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This data will be stored as a 2 byte entry in the header in the future (b1 and b2).
This commit is contained in:
Con Kolivas 2011-03-12 20:31:56 +11:00
parent 7fbec0a783
commit 1397c0f832
2 changed files with 35 additions and 1 deletions
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31
lrzip.c
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@ -35,6 +35,7 @@
#include <errno.h>
#endif
#include <sys/time.h>
#include <math.h>
#include "md5.h"
#include "rzip.h"
@ -44,6 +45,36 @@
#define MAGIC_LEN (39)
/* Determine how many times to hash the password when encrypting, based on
* the date such that we increase the number of loops according to Moore's
* law relative to when the data is encrypted. It is then stored as a two
* byte value in the header */
#define MOORE 1.835 // world constant [TIMES per YEAR]
#define ARBITRARY 1000000 // number of sha2 calls per one second in 2011
#define T_ZERO 1293840000 // seconds since epoch in 2011
#define SECONDS_IN_A_YEAR (365*86400)
#define MOORE_TIMES_PER_SECOND pow (MOORE, 1.0 / SECONDS_IN_A_YEAR)
#define ARBITRARY_AT_EPOCH (ARBITRARY * pow (MOORE_TIMES_PER_SECOND, -T_ZERO))
static i64 nloops(i64 seconds, uchar *b1, uchar *b2)
{
i64 nloops_encoded, nloops;
int nbits;
nloops = ARBITRARY_AT_EPOCH * pow(MOORE_TIMES_PER_SECOND, seconds);
nbits = log (nloops) / M_LN2;
*b1 = nbits - 7;
*b2 = nloops >> *b1;
nloops_encoded = (i64)*b2 << (i64)*b1;
return nloops_encoded;
}
static i64 enc_loops(uchar b1, uchar b2)
{
return (i64)b2 << (i64)b1;
}
static char *make_magic(rzip_control *control, int fd_in)
{
struct timeval tv;

5
lrzip_private.h
View file

@ -181,7 +181,10 @@ struct rzip_control {
i64 st_size;
long page_size;
int fd_out;
int encrypt;
char encrypt;
i64 encloops;
uchar loop_byte1;
uchar loop_byte2;
i64 secs;
i64 usecs;
unsigned char eof;