i2c md 1 0x50
时间: 2023-09-27 16:06:31 浏览: 133
这条命令看起来像是在使用 i2c 工具对地址为 0x50 的设备进行读取操作。i2c 是一种串行总线协议,用于连接各种外设,可以进行读写操作,md 是 i2c 工具中的一个命令,表示进行内存读取操作。因此这条命令的含义是从地址为 0x50 的设备中读取内存数据,并将其打印出来。如果您需要更详细的解答,请提供更多上下文信息。
相关问题
md5哈希算法c实现
MD5是一种常用的哈希算法,它将任意长度的消息压缩成一个128位的消息摘要(或称为指纹)。下面是一个简单的C语言实现:
```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#define LEFTROTATE(x, c) (((x) << (c)) | ((x) >> (32 - (c))))
void md5(uint8_t *initial_msg, size_t initial_len, uint8_t *digest) {
uint32_t h0, h1, h2, h3;
uint8_t *msg = NULL;
// 初始化常量
uint32_t k[] = {
0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5,
0x3956c25b, 0x59f111f1, 0x923f82a4, 0xab1c5ed5,
0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3,
0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174,
0xe49b69c1, 0xefbe4786, 0x0fc19dc6, 0x240ca1cc,
0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da,
0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7,
0xc6e00bf3, 0xd5a79147, 0x06ca6351, 0x14292967,
0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13,
0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85,
0xa2bfe8a1, 0xa81a664b, 0xc24b8b70, 0xc76c51a3,
0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070,
0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5,
0x391c0cb3, 0x4ed8aa4a, 0x5b9cca4f, 0x682e6ff3,
0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208,
0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2
};
// 初始化变量
uint32_t a, b, c, d, i, j;
// 初始化消息
size_t new_len = ((((initial_len + 8) / 64) + 1) * 64) - 8;
msg = calloc(new_len + 64, 1);
memcpy(msg, initial_msg, initial_len);
msg[initial_len] = 128;
uint32_t bits_len = 8 * initial_len;
memcpy(msg + new_len, &bits_len, 4);
// 初始化哈希值
h0 = 0x67452301;
h1 = 0xefcdab89;
h2 = 0x98badcfe;
h3 = 0x10325476;
// 处理消息
for (i = 0; i < new_len; i += 64) {
a = h0;
b = h1;
c = h2;
d = h3;
uint32_t *chunk = (uint32_t *)(msg + i);
uint32_t *w = (uint32_t *)calloc(64, 1);
for (j = 0; j < 16; j++) {
w[j] = chunk[j];
}
for (j = 16; j < 64; j++) {
uint32_t s0 = LEFTROTATE(w[j - 15], 7) ^ LEFTROTATE(w[j - 15], 18) ^ (w[j - 15] >> 3);
uint32_t s1 = LEFTROTATE(w[j - 2], 17) ^ LEFTROTATE(w[j - 2], 19) ^ (w[j - 2] >> 10);
w[j] = w[j - 16] + s0 + w[j - 7] + s1;
}
for (j = 0; j < 64; j++) {
uint32_t s0 = LEFTROTATE(a, 12) ^ LEFTROTATE(a, 25) ^ LEFTROTATE(a, 27);
uint32_t maj = (a & b) ^ (a & c) ^ (b & c);
uint32_t t2 = s0 + maj;
uint32_t s1 = LEFTROTATE(d, 5) ^ LEFTROTATE(d, 13) ^ LEFTROTATE(d, 22);
uint32_t ch = (d & b) ^ ((~d) & c);
uint32_t t1 = h[j] + s1 + ch + k[j] + w[j];
d = c;
c = b;
b = a;
a = t1 + t2;
}
h0 += a;
h1 += b;
h2 += c;
h3 += d;
free(w);
}
// 生成摘要
memcpy(digest, &h0, 4);
memcpy(digest + 4, &h1, 4);
memcpy(digest + 8, &h2, 4);
memcpy(digest + 12, &h3, 4);
free(msg);
}
int main(int argc, char **argv) {
uint8_t digest[16];
char *msg = "hello world";
md5((uint8_t *)msg, strlen(msg), digest);
printf("MD5(\"%s\") = ", msg);
for (int i = 0; i < 16; i++) {
printf("%02x", digest[i]);
}
printf("\n");
return 0;
}
```
这个实现使用了标准的MD5算法,包括初始化常量、初始化变量、消息处理和生成摘要等步骤。你可以将任意长度的消息传递给`md5`函数,它将返回一个16字节的摘要。
c 实现md5加密
MD5是一种哈希算法,可以将任意长度的数据映射为128位的哈希值。下面是C语言实现MD5加密的示例代码:
```c
#include <stdio.h>
#include <string.h>
#include <stdint.h>
#define LEFTROTATE(x, c) (((x) << (c)) | ((x) >> (32 - (c))))
void md5(uint8_t *initial_msg, size_t initial_len, uint8_t *digest) {
//定义变量
uint32_t h0, h1, h2, h3;
uint8_t *msg = NULL;
uint32_t *chunks = NULL;
size_t new_len, offset;
uint32_t a, b, c, d, f, g, temp;
uint32_t r[] = {
7, 12, 17, 22,
7, 12, 17, 22,
7, 12, 17, 22,
7, 12, 17, 22
};
uint32_t k[] = {
0xd76aa478, 0xe8c7b756, 0x242070db, 0xc1bdceee,
0xf57c0faf, 0x4787c62a, 0xa8304613, 0xfd469501,
0x698098d8, 0x8b44f7af, 0xffff5bb1, 0x895cd7be,
0x6b901122, 0xfd987193, 0xa679438e, 0x49b40821,
0xf61e2562, 0xc040b340, 0x265e5a51, 0xe9b6c7aa,
0xd62f105d, 0x2441453, 0xd8a1e681, 0xe7d3fbc8,
0x21e1cde6, 0xc33707d6, 0xf4d50d87, 0x455a14ed,
0xa9e3e905, 0xfcefa3f8, 0x676f02d9, 0x8d2a4c8a,
0xfffa3942, 0x8771f681, 0x6d9d6122, 0xfde5380c,
0xa4beea44, 0x4bdecfa9, 0xf6bb4b60, 0xbebfbc70,
0x289b7ec6, 0xeaa127fa, 0xd4ef3085, 0x4881d05,
0xd9d4d039, 0xe6db99e5, 0x1fa27cf8, 0xc4ac5665,
0xf4292244, 0x432aff97, 0xab9423a7, 0xfc93a039,
0x655b59c3, 0x8f0ccc92, 0xffeff47d, 0x85845dd1,
0x6fa87e4f, 0xfe2ce6e0, 0xa3014314, 0x4e0811a1,
0xf7537e82, 0xbd3af235, 0x2ad7d2bb, 0xeb86d391
};
//初始化变量
h0 = 0x67452301;
h1 = 0xefcdab89;
h2 = 0x98badcfe;
h3 = 0x10325476;
//将消息填充为512位块的倍数
new_len = ((((initial_len + 8) / 64) + 1) * 64) - 8;
msg = calloc(new_len + 64, 1);
memcpy(msg, initial_msg, initial_len);
msg[initial_len] = 128;
offset = initial_len + 1;
while (offset < new_len) {
msg[offset] = 0;
offset++;
}
*((uint64_t *)(msg + new_len)) = (uint64_t)initial_len * 8;
//处理消息
chunks = (uint32_t *)msg;
for (offset = 0; offset < new_len; offset += 64) {
a = h0;
b = h1;
c = h2;
d = h3;
for (int i = 0; i < 64; i++) {
if (i < 16) {
f = (b & c) | ((~b) & d);
g = i;
} else if (i < 32) {
f = (d & b) | ((~d) & c);
g = (5 * i + 1) % 16;
} else if (i < 48) {
f = b ^ c ^ d;
g = (3 * i + 5) % 16;
} else {
f = c ^ (b | (~d));
g = (7 * i) % 16;
}
temp = d;
d = c;
c = b;
b = b + LEFTROTATE((a + f + k[i] + chunks[g]), r[i]);
a = temp;
}
h0 += a;
h1 += b;
h2 += c;
h3 += d;
}
//将结果转化为字节数组
memcpy(digest, &h0, 4);
memcpy(digest + 4, &h1, 4);
memcpy(digest + 8, &h2, 4);
memcpy(digest + 12, &h3, 4);
//释放内存
free(msg);
}
int main() {
//测试
char *msg = "hello world";
uint8_t digest[16];
md5((uint8_t *)msg, strlen(msg), digest);
for (int i = 0; i < 16; i++) {
printf("%02x", digest[i]);
}
printf("\n");
return 0;
}
```
注意,这里的MD5实现仅供学习和参考,实际应用中应该使用更安全的加密算法。
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