高手请进，关于伪随机数生成器的实现。至少200分。
首先说明不是函数库里面的random（）函数，那个生成的随机数不安全。
这里要求的是在密码学安全领域相对安全的伪随机数生成器。
生成数的周期至少要2的200次方以上。
谢谢各位高手指导，不知道的麻烦up下，谢谢。
麻烦各位指明下参考什么材料。谢谢。！！
问题点数：100、回复次数：32Top
1 楼flying_dancing（小混混-_-）回复于 2005-05-08 18:21:22 得分 1
伪随机数???为什么不安全Top
2 楼flying_dancing（小混混-_-）回复于 2005-05-08 18:21:52 得分 1
random（）函数，那个生成的随机数不安全??为什么不安全
刚才问错Top
3 楼lbing7（向青润老大学习!!!）回复于 2005-05-08 18:24:22 得分 1
生成数的周期至少要2的200次方以上。
本来就是随机的,为什么要规定生成周期呢?
想不通,规定了生成周期还是你要的"安全的"吗?Top
4 楼ltc_mouse（野地芳菲）回复于 2005-05-08 19:28:46 得分 1
生成数的周期至少要2的200次方以上。
呵呵，首先要找到能生成这么长周期的公式吧。按公式生成就是了～Top
5 楼diaoni（三条腿的废柴）回复于 2005-05-08 20:23:14 得分 1
将一个与系统有关的数值（例如系统时间）mod上2的200次方然后再做一次线形变换
这样不知行不行？Top
6 楼jingyueid（干宁）回复于 2005-05-08 20:31:49 得分 3
楼主是为了防止随机数破解？？
TO：楼上的，那种做法无意义，2的200次方，表现困难不说，计算机产生的随机数也没有那样的精度。
你可以提供多种方案啊，用产生的随机数做种子再生成新的随机数，或者将内存中的某个自动变量的地址等等只要方法不单一，破解能力就会下降。
加密技术里不也有多种方法组合吗？Top
7 楼mostideal（三甲）回复于 2005-05-08 20:34:42 得分 1
这个我不知道，，帮你顶了。/。Top
8 楼somedummy（某人马甲）回复于 2005-05-08 21:01:32 得分 5
可以说相当不易……
C标准库里面的RAND_MAX一般也就是32767（VC++和gcc都是这么大），对于这样的东西来说，循环周期要达到2^200困难相当大，因为作为一个产生随机数的源，不可能太大，最多也就2^10个数而已。因此最大的可能就是想办法改变中间选择随机数值的过程，并且减少每次选择的相关性。选择多个不相关的随机化种子是一种可能的解决方案，一般选择的是时间，再加上一些其他的和运行空间相关的量也许可以。
不过我觉得，其实可以使用rtdsc指令这样的东西辅助以产生随机数种子比较好，因为你不知道你的程序的运行过程中的系统会产生多少中断的调用，以及你的系统的进程运行情况。
以上仅供参考……Top
9 楼thewintersun（巴斯光年）回复于 2005-05-09 18:48:31 得分 0
程序是纯软件的，不借助于硬件。
如果能借助于硬件就能产生真随机数了。
安全只是理论上相对安全。
编译器提供的函数周期太少，攻击者容易根据生成的规律破译它。
Top
10 楼somedummy（某人马甲）回复于 2005-05-09 21:14:15 得分 1
不借助于硬件是不太现实的，你能找到那么多完全可以通过关键取得的随机量？Top
11 楼du51（郁郁思扬）回复于 2005-05-09 21:26:33 得分 1
防真?
猜的.错了,别骂.Top
12 楼guyaguya（我只愿面朝大海，春暖花开）回复于 2005-05-09 21:29:38 得分 1
学习Top
13 楼Melody1508（披着羊皮的狼）回复于 2005-05-09 21:30:36 得分 1
upTop
14 楼Zz_Benjin（）回复于 2005-05-10 08:38:24 得分 37
////////////////////////////////////////////////////////////////////////////////
//
// MyRandom.CPP: Marsaglia的"mother"随机数生成函数
//
////////////////////////////////////////////////////////////////////////////////
//#include "DgRandom.h"
#include <iostream>
#include <string.h>
using namespace std;
static short mother1[10];
static short mother2[10];
static short mStart=1;
#define m16Long 65536L /* 2^16 */
#define m16Mask 0xFFFF /* mask for lower 16 bits */
#define m15Mask 0x7FFF /* mask for lower 15 bits */
#define m31Mask 0x7FFFFFFF /* mask for 31 bits */
#define m32Double 4294967295.0 /* 2^32-1 */
/* Mother *****************************************************************
| George Marsaglia's The mother of all random number generators producing
| uniformly distributed pseudo random 32 bit values with period about 2^250.
|
| The text of Marsaglia's posting is appended at the end of the function.
|
| The arrays mother1 and mother2 store carry values in their first element,
| and random 16 bit numbers in elements 1 to 8.
|
| These random numbers are moved to elements 2 to 9 and a new carry and
| number are generated and placed in elements 0 and 1.
|
| The arrays mother1 and mother2 are filled with random 16 bit values on
| first call of Mother by another generator. mStart is the switch.
|
| Returns:
| A 32 bit random number is obtained by combining the output of the two
| generators and returned in *pSeed. It is also scaled by 2^32-1 and re-
| turned as a double between 0 and 1
|
| SEED:
| The inital value of *pSeed may be any long value
|
| Bob Wheeler 8/8/94
**************************************************************************/
static double Mother(unsigned long *pSeed)
{
unsigned long number, number1, number2;
short n, *p;
unsigned short sNumber;
/* Initialize motheri with 9 random values the first time */
if (mStart)
{
sNumber= *pSeed&m16Mask; /* The low 16 bits */
number= *pSeed&m31Mask; /* Only want 31 bits */
p=mother1;
for (n=18;n--;)
{
number=30903*sNumber+(number>>16); /* One line multiply-with-cary */
*p++=sNumber=number&m16Mask;
if (n==9)
p=mother2;
}
/* make cary 15 bits */
mother1[0]&=m15Mask;
mother2[0]&=m15Mask;
mStart=0;
}
/* Move elements 1 to 8 to 2 to 9 */
memmove(mother1+2,mother1+1,8*sizeof(short));
memmove(mother2+2,mother2+1,8*sizeof(short));
/* Put the carry values in numberi */
number1=mother1[0];
number2=mother2[0];
/* Form the linear combinations */
number1+=1941*mother1[2]+1860*mother1[3]+1812*mother1[4]+1776*mother1[5]+
1492*mother1[6]+1215*mother1[7]+1066*mother1[8]+12013*mother1[9];
number2+=1111*mother2[2]+2222*mother2[3]+3333*mother2[4]+4444*mother2[5]+
5555*mother2[6]+6666*mother2[7]+7777*mother2[8]+9272*mother2[9];
/* Save the high bits of numberi as the new carry */
mother1[0]=number1/m16Long;
mother2[0]=number2/m16Long;
/* Put the low bits of numberi into motheri[1] */
mother1[1]=m16Mask&number1;
mother2[1]=m16Mask&number2;
/* Combine the two 16 bit random numbers into one 32 bit */
*pSeed=(((long)mother1[1])<<16)+(long)mother2[1];
/* Return a double value between 0 and 1 */
return ((double)*pSeed)/m32Double;
}
Top
15 楼Zz_Benjin（）回复于 2005-05-10 08:38:46 得分 0
/*******************************************************************************
Marsaglia's comments
Yet another RNG
Random number generators are frequently posted on the network; my colleagues and
I posted ULTRA in 1992 and, from the number of requests for releases to use it in
software packages, it seems to be widely used.
I have long been interested in RNG's and several of my early ones are used as sy-
stem generators or in statistical packages.
So why another one? And why here?
Because I want to describe a generator, or rather, a class of generators, so pro-
mising I am inclined to call it
The Mother of All Random Number Generators
and because the generator seems promising enough to justify shortcutting the many
months, even years, before new developments are widely known through publication
in a journal.
This new class leads to simple, fast programs that produce sequences with very long
periods. They use multiplication, which experience has shown does a better job of
mixing bits than do +,- or exclusive-or, and they do it with easily-implemented ar-
ithmetic modulo a power of 2, unlike arithmetic modulo a prime. The latter, while
satisfactory, is difficult to implement. But the arithmetic here modulo 2^16 or 2^32
does not suffer the flaws of ordinary congruential generators for those moduli:
trailing bits too regular. On the contrary, all bits of the integers produced by
this new method, whether leading or trailing, have passed extensive tests of random-
ness.
Here is an idea of how it works, using, say, integers of six decimal digits from wh-
ich we return random 3-digit integers. Start with n=123456, the seed.
Then form a new n=672*456+123=306555 and return 555.
Then form a new n=672*555+306=373266 and return 266.
Then form a new n=672*266+373=179125 and return 125,
and so on. Got it? This is a multiply-with-carry sequence x(n)=672*x(n-1)+ carry
mod b=1000, where the carry is the number of b's dropped in the modular reduction.
The resulting sequence of 3-digit x's has period 335,999. Try it.
No big deal, but that's just an example to give the idea. Now consider the sequence
of 16-bit integers produced by the two C statements:
k=30903*(k&65535)+(k>>16); return(k&65535);
Notice that it is doing just what we did in the example:
multiply the bottom half (by 30903, carefully chosen), add the top half and return
the new bottom.
That will produce a sequence of 16-bit integers with period > 2^29, and if we conc-
atenate two such:
k=30903*(k&65535)+(k>>16);
j=18000*(j&65535)+(j>>16);
return((k<<16)+j);
we get a sequence of more than 2^59 32-bit integers before cycling.
The following segment in a (properly initialized) C procedure will generate more than
2^118 32-bit random integers from six random seed values i,j,k,l,m,n:
k=30903*(k&65535)+(k>>16);
j=18000*(j&65535)+(j>>16);
i=29013*(i&65535)+(i>>16);
l=30345*(l&65535)+(l>>16);
m=30903*(m&65535)+(m>>16);
n=31083*(n&65535)+(n>>16);
return((k+i+m)>>16)+j+l+n);
And it will do it much faster than any of several widely used generators designed to
use 16-bit integer arithmetic, such as that of Wichman-Hill that combines congruential
sequences for three 15-bit primes (Applied Statistics, v31, p188-190, 1982), period
about 2^42.
I call these multiply-with-carry generators. Here is an extravagant 16-bit example that
is easily implemented in C or Fortran. It does such a thorough job of mixing the bits
of the previous eight values that it is difficult to imagine a test of randomness it
could not pass:
x[n]=12013x[n-8]+1066x[n-7]+1215x[n-6]+1492x[n-5]+1776x[n-4]
+1812x[n-3]+1860x[n-2]+1941x[n-1]+carry mod 2^16.
The linear combination occupies at most 31 bits of a 32-bit integer. The bottom 16 is
the output, the top 15 the next carry. It is probably best to implement with 8 case
segments. It takes 8 microseconds on my PC. Of course it just provides 16-bit random
integers, but awfully good ones. For 32 bits you would have to combine it with another,
such as
x[n]=9272x[n-8]+7777x[n-7]+6666x[n-6]+5555x[n-5]+4444x[n-4]
+3333x[n-3]+2222x[n-2]+1111x[n-1]+carry mod 2^16.
Concatenating those two gives a sequence of 32-bit random integers (from 16 random 16-
bit seeds), period about 2^250. It is so awesome it may merit the Mother of All RNG's
title.
The coefficients in those two linear combinations suggest that it is easy to get long-
period sequences, and that is true. The result is due to Cemal Kac, who extended the
theory we gave for add-with-carry sequences: Choose a base b and give r seed values x[1],
...,x[r] and an initial 'carry' c. Then the multiply-with-carry sequence
x[n]=a1*x[n-1]+a2*x[n-2]+...+ar*x[n-r]+carry mod b,
where the new carry is the number of b's dropped in the modular reduction, will have
period the order of b in the group of residues relatively prime to m=ar*b^r+...+a1b^1-1.
Furthermore, the x's are, in reverse order, the digits in the expansion of k/m to the
base b, for some 0<k<m.
In practice b=2^16 or b=2^32 allows the new integer and the new carry to be the bottom
and top half of a 32- or 64-bit linear combination of 16- or 32-bit integers. And it
is easy to find suitable m's if you have a primality test: just search through candi-
date coefficients until you get an m that is a safeprime---both m and (m-1)/2 are prime. Then the period of the multiply-with-
carry sequence will be the prime (m-1)/2. (It can't be m-1 because b=2^16 or 2^32 is a
square.)
Here is an interesting simple MWC generator with period> 2^92, for 32-bit arithmetic:
x[n]=1111111464*(x[n-1]+x[n-2]) + carry mod 2^32.
Suppose you have functions, say top() and bot(), that give the top and bottom halves of
a 64-bit result. Then, with initial 32-bit x, y and carry c, simple statements such as
y=bot(1111111464*(x+y)+c)
x=y
c=top(y)
will, repeated, give over 2^92 random 32-bit y's.
Not many machines have 64 bit integers yet. But most assemblers for modern CPU's permit
access to the top and bottom halves of a 64-bit product.
I don't know how to readily access the top half of a 64-bit product in C. Can anyone
suggest how it might be done? (in integer arithmetic)
George Marsaglia geo@stat.fsu.edu
*******************************************************************************/
////////////////////////////////////////////////////////////////////////////////
////////////////////////////////////////////////////////////////////////////////
Top
16 楼Zz_Benjin（）回复于 2005-05-10 08:42:42 得分 0
老兄，这是号称周期为2的250次方的伪随机数生产函数，应该能满足你的要求了吧？具体算法看上面的英文注释！Top
17 楼domestic007（杀猪的）回复于 2005-05-10 08:51:08 得分 1
顶Top
18 楼diaoni（三条腿的废柴）回复于 2005-05-10 10:22:37 得分 1
强!学习ing...Top
19 楼dzw2004（深蓝）回复于 2005-05-10 10:44:27 得分 1
好长！好强！up！~Top
20 楼bzCpp（csdn总技术值班室之饼子堂）回复于 2005-05-10 14:11:09 得分 35
openssl 上的:
static void ssleay_rand_add(const void *buf, int num, double add)
{
int i,j,k,st_idx;
long md_c[2];
unsigned char local_md[MD_DIGEST_LENGTH];
EVP_MD_CTX m;
int do_not_lock;
/*
* (Based on the rand(3) manpage)
*
* The input is chopped up into units of 20 bytes (or less for
* the last block). Each of these blocks is run through the hash
* function as follows: The data passed to the hash function
* is the current 'md', the same number of bytes from the 'state'
* (the location determined by in incremented looping index) as
* the current 'block', the new key data 'block', and 'count'
* (which is incremented after each use).
* The result of this is kept in 'md' and also xored into the
* 'state' at the same locations that were used as input into the
* hash function.
*/
/* check if we already have the lock */
if (crypto_lock_rand)
{
CRYPTO_r_lock(CRYPTO_LOCK_RAND2);
do_not_lock = (locking_thread == CRYPTO_thread_id());
CRYPTO_r_unlock(CRYPTO_LOCK_RAND2);
}
else
do_not_lock = 0;
if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
st_idx=state_index;
/* use our own copies of the counters so that even
* if a concurrent thread seeds with exactly the
* same data and uses the same subarray there's _some_
* difference */
md_c[0] = md_count[0];
md_c[1] = md_count[1];
memcpy(local_md, md, sizeof md);
/* state_index <= state_num <= STATE_SIZE */
state_index += num;
if (state_index >= STATE_SIZE)
{
state_index%=STATE_SIZE;
state_num=STATE_SIZE;
}
else if (state_num < STATE_SIZE)
{
if (state_index > state_num)
state_num=state_index;
}
/* state_index <= state_num <= STATE_SIZE */
/* state[st_idx], ..., state[(st_idx + num - 1) % STATE_SIZE]
* are what we will use now, but other threads may use them
* as well */
md_count[1] += (num / MD_DIGEST_LENGTH) + (num % MD_DIGEST_LENGTH > 0);
if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
EVP_MD_CTX_init(&m);
for (i=0; i<num; i+=MD_DIGEST_LENGTH)
{
j=(num-i);
j=(j > MD_DIGEST_LENGTH)?MD_DIGEST_LENGTH:j;
MD_Init(&m);
MD_Update(&m,local_md,MD_DIGEST_LENGTH);
k=(st_idx+j)-STATE_SIZE;
if (k > 0)
{
MD_Update(&m,&(state[st_idx]),j-k);
MD_Update(&m,&(state[0]),k);
}
else
MD_Update(&m,&(state[st_idx]),j);
MD_Update(&m,buf,j);
MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
MD_Final(&m,local_md);
md_c[1]++;
buf=(const char *)buf + j;
for (k=0; k<j; k++)
{
/* Parallel threads may interfere with this,
* but always each byte of the new state is
* the XOR of some previous value of its
* and local_md (itermediate values may be lost).
* Alway using locking could hurt performance more
* than necessary given that conflicts occur only
* when the total seeding is longer than the random
* state. */
state[st_idx++]^=local_md[k];
if (st_idx >= STATE_SIZE)
st_idx=0;
}
}
EVP_MD_CTX_cleanup(&m);
if (!do_not_lock) CRYPTO_w_lock(CRYPTO_LOCK_RAND);
/* Don't just copy back local_md into md -- this could mean that
* other thread's seeding remains without effect (except for
* the incremented counter). By XORing it we keep at least as
* much entropy as fits into md. */
for (k = 0; k < sizeof md; k++)
{
md[k] ^= local_md[k];
}
if (entropy < ENTROPY_NEEDED) /* stop counting when we have enough */
entropy += add;
if (!do_not_lock) CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
#if !defined(OPENSSL_THREADS) && !defined(OPENSSL_SYS_WIN32)
assert(md_c[1] == md_count[1]);
#endif
}Top
21 楼bzCpp（csdn总技术值班室之饼子堂）回复于 2005-05-10 14:11:33 得分 0
static int ssleay_rand_bytes(unsigned char *buf, int num)
{
static volatile int stirred_pool = 0;
int i,j,k,st_num,st_idx;
int num_ceil;
int ok;
long md_c[2];
unsigned char local_md[MD_DIGEST_LENGTH];
EVP_MD_CTX m;
#ifndef GETPID_IS_MEANINGLESS
pid_t curr_pid = getpid();
#endif
int do_stir_pool = 0;
#ifdef PREDICT
if (rand_predictable)
{
static unsigned char val=0;
for (i=0; i<num; i++)
buf[i]=val++;
return(1);
}
#endif
if (num <= 0)
return 1;
EVP_MD_CTX_init(&m);
/* round upwards to multiple of MD_DIGEST_LENGTH/2 */
num_ceil = (1 + (num-1)/(MD_DIGEST_LENGTH/2)) * (MD_DIGEST_LENGTH/2);
/*
* (Based on the rand(3) manpage:)
*
* For each group of 10 bytes (or less), we do the following:
*
* Input into the hash function the local 'md' (which is initialized from
* the global 'md' before any bytes are generated), the bytes that are to
* be overwritten by the random bytes, and bytes from the 'state'
* (incrementing looping index). From this digest output (which is kept
* in 'md'), the top (up to) 10 bytes are returned to the caller and the
* bottom 10 bytes are xored into the 'state'.
*
* Finally, after we have finished 'num' random bytes for the
* caller, 'count' (which is incremented) and the local and global 'md'
* are fed into the hash function and the results are kept in the
* global 'md'.
*/
CRYPTO_w_lock(CRYPTO_LOCK_RAND);
/* prevent ssleay_rand_bytes() from trying to obtain the lock again */
CRYPTO_w_lock(CRYPTO_LOCK_RAND2);
locking_thread = CRYPTO_thread_id();
CRYPTO_w_unlock(CRYPTO_LOCK_RAND2);
crypto_lock_rand = 1;
if (!initialized)
{
RAND_poll();
initialized = 1;
}
if (!stirred_pool)
do_stir_pool = 1;
ok = (entropy >= ENTROPY_NEEDED);
if (!ok)
{
/* If the PRNG state is not yet unpredictable, then seeing
* the PRNG output may help attackers to determine the new
* state; thus we have to decrease the entropy estimate.
* Once we've had enough initial seeding we don't bother to
* adjust the entropy count, though, because we're not ambitious
* to provide *information-theoretic* randomness.
*
* NOTE: This approach fails if the program forks before
* we have enough entropy. Entropy should be collected
* in a separate input pool and be transferred to the
* output pool only when the entropy limit has been reached.
*/
entropy -= num;
if (entropy < 0)
entropy = 0;
}
if (do_stir_pool)
{
/* In the output function only half of 'md' remains secret,
* so we better make sure that the required entropy gets
* 'evenly distributed' through 'state', our randomness pool.
* The input function (ssleay_rand_add) chains all of 'md',
* which makes it more suitable for this purpose.
*/
int n = STATE_SIZE; /* so that the complete pool gets accessed */
while (n > 0)
{
#if MD_DIGEST_LENGTH > 20
# error "Please adjust DUMMY_SEED."
#endif
#define DUMMY_SEED "...................." /* at least MD_DIGEST_LENGTH */
/* Note that the seed does not matter, it's just that
* ssleay_rand_add expects to have something to hash. */
ssleay_rand_add(DUMMY_SEED, MD_DIGEST_LENGTH, 0.0);
n -= MD_DIGEST_LENGTH;
}
if (ok)
stirred_pool = 1;
}
st_idx=state_index;
st_num=state_num;
md_c[0] = md_count[0];
md_c[1] = md_count[1];
memcpy(local_md, md, sizeof md);
state_index+=num_ceil;
if (state_index > state_num)
state_index %= state_num;
/* state[st_idx], ..., state[(st_idx + num_ceil - 1) % st_num]
* are now ours (but other threads may use them too) */
md_count[0] += 1;
/* before unlocking, we must clear 'crypto_lock_rand' */
crypto_lock_rand = 0;
CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
while (num > 0)
{
/* num_ceil -= MD_DIGEST_LENGTH/2 */
j=(num >= MD_DIGEST_LENGTH/2)?MD_DIGEST_LENGTH/2:num;
num-=j;
MD_Init(&m);
#ifndef GETPID_IS_MEANINGLESS
if (curr_pid) /* just in the first iteration to save time */
{
MD_Update(&m,(unsigned char*)&curr_pid,sizeof curr_pid);
curr_pid = 0;
}
#endif
MD_Update(&m,local_md,MD_DIGEST_LENGTH);
MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
#ifndef PURIFY
MD_Update(&m,buf,j); /* purify complains */
#endif
k=(st_idx+MD_DIGEST_LENGTH/2)-st_num;
if (k > 0)
{
MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2-k);
MD_Update(&m,&(state[0]),k);
}
else
MD_Update(&m,&(state[st_idx]),MD_DIGEST_LENGTH/2);
MD_Final(&m,local_md);
for (i=0; i<MD_DIGEST_LENGTH/2; i++)
{
state[st_idx++]^=local_md[i]; /* may compete with other threads */
if (st_idx >= st_num)
st_idx=0;
if (i < j)
*(buf++)=local_md[i+MD_DIGEST_LENGTH/2];
}
}
MD_Init(&m);
MD_Update(&m,(unsigned char *)&(md_c[0]),sizeof(md_c));
MD_Update(&m,local_md,MD_DIGEST_LENGTH);
CRYPTO_w_lock(CRYPTO_LOCK_RAND);
MD_Update(&m,md,MD_DIGEST_LENGTH);
MD_Final(&m,md);
CRYPTO_w_unlock(CRYPTO_LOCK_RAND);
EVP_MD_CTX_cleanup(&m);
if (ok)
return(1);
else
{
RANDerr(RAND_F_SSLEAY_RAND_BYTES,RAND_R_PRNG_NOT_SEEDED);
ERR_add_error_data(1, "You need to read the OpenSSL FAQ, "
"http://www.openssl.org/support/faq.html");
return(0);
}
}Top
22 楼bzCpp（csdn总技术值班室之饼子堂）回复于 2005-05-10 14:24:57 得分 0
要产生密码学意义上安全的随机数, 一个强的随机数种子的产生是很重要的,在 linux/unix 下可以读大概是以下几个文件: "/dev/urandom","/dev/random","/dev/srandom" , 在 WIN32 下可以用 CryptGenRandom 产生随机数种子, 另外可以读取 当前屏幕的内容做随机数种子, 一个好的实现通常会在程序退出时将当前的随机数发生器状态 加密保存为一个文件,做为下次使用时的随机数种子的一部分,另外,程序应该在获取到一些随机性的事件(如鼠标键盘等事件)的时候更新随机数发生器.Top
23 楼arrowcy（长弓手）回复于 2005-05-10 15:05:20 得分 1
就是线性同余就可以了嘛，去查一下用哪一组参数最好就行了
或者干脆用混沌序列Top
24 楼thewintersun（巴斯光年）回复于 2005-05-12 13:16:10 得分 0
感谢 Zz_Benjin() 和 bzCpp(csdn总技术值班室之饼子堂)
Zz_Benjin() ：你的mother算法不错，周期也满足要求，但是不知道周期是根据什么算出来的。
如果用实际生成来测试点话，那要生成2^200个数，估计电脑几年都算不完。
能不能有周期可以控制的算法。
还请各位指教。！！Top
25 楼thewintersun（巴斯光年）回复于 2005-05-13 14:45:35 得分 0
upTop
26 楼ziren235（飞鹰）回复于 2005-05-13 15:05:19 得分 1
ding
有没有源代码可以借用？Top
27 楼thewintersun（巴斯光年）回复于 2005-05-13 23:32:25 得分 0
问题到现在基本上差不多了。
下回登陆结贴。Top
28 楼mostideal（三甲）回复于 2005-05-14 00:06:18 得分 1
dingTop
29 楼foochow（无聊,灌水......）回复于 2005-05-14 00:12:15 得分 1
UP学习下Top
30 楼horisly（SUN YAT-SEN UNIVERSITY (逸仙先生)）回复于 2005-05-14 00:57:01 得分 1
学习。慢慢研究，最近正好需要这个东西Top
31 楼hbyufan（）回复于 2005-05-14 05:32:37 得分 1
upTop
32 楼MagicCarmack（MagiC++）回复于 2005-05-14 06:17:41 得分 1
慢慢研究Top
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