现代计算机可以计算多少个SHA256哈希值？ [英] How many SHA256 hashes can a modern computer compute?

问题描述

例如，仅使用7个字母的US-ASCII字母字符，我们就会知道，知道可以使用26个可能的序列。知道计算机每分钟可以产生多少这些数据，可以让我了解产生所有可能的哈希以及破解某个7个字符的哈希（生日攻击除了）需要多长时间。例如，考虑到上面的数字，如果现代四核可以每分钟产生100万次散列，则需要 8031810176/1000000/60 = 133.86 小时，以找到该范围内的所有可能的散列。

另外，带有本地AES的新Sandy Bridge英特尔芯片如何发挥这一作用？

/ p>

解决方案

我使用OpenSSL SHA256实现在C中编写了这个测试。

  #include< stdio.h> 
 #include< string.h> 
 #includeopenssl / sha.h
 
 // http://stackoverflow.com/questions/4764608/generate-all-strings-under-length-n-in-c / 4764686＃4764686 
 int（char * str）{
 if（！str [0]）return 0; 
 
 if（str [0] =='z'）{
 str [0] ='a'; 
 return inc（str + sizeof（char））; 
} 
 
 str [0] ++; 
返回1; 
} 
 
 unsigned char buffer [65]; 
 char * hashstring（char * str，int len）{$ b $ char char [SHA256_DIGEST_LENGTH]; // openssl hash 
 SHA256_CTX sha256; 
 int i; // counter 
 
 SHA256_Init（& sha256）; 
 SHA256_Update（& sha256，str，len）; 
 SHA256_Final（hash，& sha256）; （i = 0; i< SHA256_DIGEST_LENGTH; i ++）{
 sprintf（buffer +（i * 2），％02x，hash [i]）的
 
; //将openssl hash转换为凡人字符串
} 
 
 return buffer; 
 
 
 int main（int argc，char * argv []）{
 int N = 4; //最大长度字符串
 char str [N + 1]; //字符串持有者
 int i; // counter 
 
 unsigned int tot = 0; //计算
 
的散列数（i = 0; i  str [N] = 0; 
 
 do {
 hashstring（str，N）; 
 tot ++; 
} while（inc（str））; 
 
 printf（％d\\\
，tot）; 
 
  

编译：

  gcc -lcrypto -O3 -o test test.c 
  

结果（我知道，我对计算机游戏不是很有创意）：

  nightcracker @ nightcracker-pc：〜/ c / sha256 $ time ./test 
 11881376 
 
 real 3m2.431s 
 user 3m2.335s 
 sys 0m0.008s 
  

因此，这是 11881376 / 182.4 = 65139 每秒散列值。然后它是 26 ^ 7/101821/3600 = 34 小时来计算所有哈希值。请注意，所有这些都是在单线程应用程序中的Q6600四核CPU上完成的，并且不包括将哈希写入文件。

编辑

Woops，我计算了所有N个字符和以下字符串的哈希值。更正并更新数据。

I want to know the mathematical time required for cracking hashes based off different sets of characters.

For example, using only 7 letter, US-ASCII alphabetic characters we know that there are 26⁷ possible sequences that could be used. Knowing how many of these could be generated by a computer each minute would give me an idea of how long it would take to generate all possible hashes and crack a certain 7 character hash (birthday attacks aside).

For example, taking the number above, if a modern quad core could generate 1 million hashes each minute it would take 8031810176 / 1000000 / 60 = 133.86 hours to find all possible hashes in that range.

Also, how does the new Sandy Bridge Intel chips with native AES play into this?

解决方案

I wrote this test in C using the OpenSSL SHA256 implementation.

#include <stdio.h>
#include <string.h>
#include "openssl/sha.h"

// http://stackoverflow.com/questions/4764608/generate-all-strings-under-length-n-in-c/4764686#4764686
int inc(char *str) {
    if (!str[0]) return 0;

    if (str[0] == 'z') {
        str[0] = 'a';
        return inc(str + sizeof(char));
    }

    str[0]++;
    return 1;
}

unsigned char buffer[65];
char* hashstring(char *str, int len) {
    char hash[SHA256_DIGEST_LENGTH]; // the openssl hash
    SHA256_CTX sha256;
    int i; // counter

    SHA256_Init(&sha256);
    SHA256_Update(&sha256, str, len);
    SHA256_Final(hash, &sha256);

    for (i = 0; i < SHA256_DIGEST_LENGTH; i++) {
        sprintf(buffer + (i * 2), "%02x", hash[i]); // convert openssl hash to mortal human string
    }

    return buffer;
}

int main(int argc, char *argv[]) {
    int N = 4; // max length string
    char str[N+1]; // the string holder
    int i; // counter

    unsigned int tot = 0; // number of hashes calculated

    for (i = 0; i < N; i++) str[i] = 'a';
    str[N] = 0;

    do {
        hashstring(str, N);
        tot++;
    } while(inc(str));

    printf("%d\n", tot);
}

Compile:

gcc -lcrypto -O3 -o test test.c

And results (I know, I'm not very creative with computernames):

nightcracker@nightcracker-pc:~/c/sha256$ time ./test
11881376

real    3m2.431s
user    3m2.335s
sys 0m0.008s

So that's 11881376 / 182.4 = 65139 hashes per second. Then it's 26^7/101821/3600 = 34 hours to compute all the hashes. Please note, all of this was done on a Q6600 quad-core CPU in a single-threaded application and excluded writing the hashes to file.

EDIT

Woops, I was calculating all the hashes of strings with N characters and below. Corrected and data updated.

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