C 应用哈希函数n次
我需要高效地实现特定哈希函数的迭代应用,例如输入xn次的SHA1,即SHA1(…SHA1(x)))。我正试图用下面的代码来实现这一点,但是这对于n=2^16来说是如此缓慢的2秒。在下面的代码中,$n$是应用SHA1、x=seedj1和temp=SHA1(…SHA1(x))的次数。你能帮我吗C 应用哈希函数n次,c,hash,C,Hash,我需要高效地实现特定哈希函数的迭代应用,例如输入xn次的SHA1,即SHA1(…SHA1(x)))。我正试图用下面的代码来实现这一点,但是这对于n=2^16来说是如此缓慢的2秒。在下面的代码中,$n$是应用SHA1、x=seedj1和temp=SHA1(…SHA1(x))的次数。你能帮我吗 int hashcwe_n1(int n, unsigned char * seedj1, unsigned char * temp) { int i, j; int r = 160; memcpy(temp
int hashcwe_n1(int n, unsigned char * seedj1, unsigned char * temp) {
int i, j;
int r = 160;
memcpy(temp, seedj1, r);
for (i = 0; i < n; i++) {
SHA1(seedj1, r, temp);
if (n % 2 != 0)
swapStrings(&temp, &seedj1);
else {
if (i == n - 1) {
memcpy(seedj1, R, r);
} else {
swapStrings(&temp, &seedj1);
}
}
}
return 1;
}
void swapStrings(unsigned char** a, unsigned char** b) {
unsigned char *temp = *a;
*a = *b;
*b = temp;
}
int hashcwe_n1(int n,无符号字符*seedj1,无符号字符*temp){
int i,j;
int r=160;
memcpy(温度、种子J1、r);
对于(i=0;i
我甚至不相信你的算法是正确的,所以衡量它的性能在某种程度上类似于在母鸡下蛋之前数鸡,更不用说在蛋孵化之前了
迭代工作负载函数没有理由表现出如此糟糕的性能,除非
- 您的SHA实现效率极低
- 您的测试平台是在Windows 3.11全新且令人兴奋时制作的
- MacBook Air(2011),Intel Core i7 Duo,4GB 1333mhz内存
- 苹果LLVM版本6.1.0(clang-602.0.53)(基于LLVM 3.6.0svn)
- OpenSSL libcrypto版本0.9.8zd 2015年1月8日
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
输出控制台
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
对于同一个示例,在Coliru上实时运行
祝你好运我甚至不相信你的算法是正确的,因此衡量它的性能在某种程度上类似于在母鸡下蛋之前数鸡,更不用说在蛋孵化之前了 迭代工作负载函数没有理由表现出如此糟糕的性能,除非
- 您的SHA实现效率极低
- 您的测试平台是在Windows 3.11全新且令人兴奋时制作的
- MacBook Air(2011),Intel Core i7 Duo,4GB 1333mhz内存
- 苹果LLVM版本6.1.0(clang-602.0.53)(基于LLVM 3.6.0svn)
- OpenSSL libcrypto版本0.9.8zd 2015年1月8日
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
输出控制台
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
对于同一个示例,在Coliru上实时运行
祝你好运我甚至不相信你的算法是正确的,因此衡量它的性能在某种程度上类似于在母鸡下蛋之前数鸡,更不用说在蛋孵化之前了 迭代工作负载函数没有理由表现出如此糟糕的性能,除非
- 您的SHA实现效率极低
- 您的测试平台是在Windows 3.11全新且令人兴奋时制作的
- MacBook Air(2011),Intel Core i7 Duo,4GB 1333mhz内存
- 苹果LLVM版本6.1.0(clang-602.0.53)(基于LLVM 3.6.0svn)
- OpenSSL libcrypto版本0.9.8zd 2015年1月8日
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
输出控制台
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
对于同一个示例,在Coliru上实时运行
祝你好运我甚至不相信你的算法是正确的,因此衡量它的性能在某种程度上类似于在母鸡下蛋之前数鸡,更不用说在蛋孵化之前了 迭代工作负载函数没有理由表现出如此糟糕的性能,除非
- 您的SHA实现效率极低
- 您的测试平台是在Windows 3.11全新且令人兴奋时制作的
- MacBook Air(2011),Intel Core i7 Duo,4GB 1333mhz内存
- 苹果LLVM版本6.1.0(clang-602.0.53)(基于LLVM 3.6.0svn)
- OpenSSL libcrypto版本0.9.8zd 2015年1月8日
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
输出控制台
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <limits.h>
#include <openssl/sha.h>
// simple hex-print utility
void hex_print(const void *buf, size_t n)
{
const unsigned char *beg = buf, *end = beg+n;
while (beg != end)
printf("%02x", *beg++);
fputc('\n', stdout);
}
// iterate n-times
void hashcwe_n
(
unsigned short n, // iteration count
void *src, // source bytes
size_t slen, // souce length
void *dst // target buffer
)
{
unsigned char md1[SHA_DIGEST_LENGTH];
unsigned char md2[SHA_DIGEST_LENGTH];
unsigned char *p1 = md1, *p2 = md2;
unsigned short i;
if (n == 0)
return;
// perform initial digest
SHA1(src, slen, md1);
// iterate the remainder of the loop
for (i=0; i<(n-1); ++i)
{
unsigned char *tmp = p1;
SHA1(p1, SHA_DIGEST_LENGTH, p2);
p1 = p2;
p2 = tmp;
}
memcpy(dst, p1, SHA_DIGEST_LENGTH);
}
// main entry point
int main()
{
unsigned char data[] = {0x61,0x62,0x63}; // "abc"
unsigned char md[SHA_DIGEST_LENGTH] = {0};
hashcwe_n(USHRT_MAX, data, sizeof(data), md);
hex_print(md, SHA_DIGEST_LENGTH);
return 0;
}
$ time ./sample
a21b4b42e20066a1046d3c81b42b7cd8a6403bf2
real 0m0.031s
user 0m0.026s
sys 0m0.003s
对于同一个示例,在Coliru上实时运行
祝你好运抛开优化不谈,你的代码看起来有点可疑。SHA1产生160位,但数组的长度似乎是160字节。另外,您正在将
R
复制到末尾的种子j1
,但此代码中没有R
。它运行是否正确?swapString()只会更改hashcwe_n1()函数参数列表中指针副本中的指针(在C中通过值传递)。撇开优化不谈,您的代码似乎有点错误。SHA1产生160位,但数组的长度似乎是160字节。另外,您正在将R
复制到末尾的种子j1
,但此代码中没有R
。它运行是否正确?swapString()只会更改hashcwe_n1()函数参数列表中指针副本中的指针(在C中通过值传递)。撇开优化不谈,您的代码似乎有点错误。SHA1产生160位,但数组的长度似乎是160字节。另外,您正在将R
复制到末尾的种子j1
,但此代码中没有R
。它运行是否正确?swapString()只更改hashcwe_n1()函数参数列表中指针副本中的指针(在C中通过值传递)