init repo

server/Diffie_hellman.c

@@ -0,0 +1,144 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <time.h>
+#include <gmp.h>
+#include <string.h>
+typedef struct{
+	mpz_t prime;
+	mpz_t base;
+	mpz_t private_key;
+	mpz_t public_key;
+	mpz_t key;	//g^(AB)
+	FILE *urand;
+}Dh_key;
+void generate_random(size_t sz, unsigned char* random_bytes,Dh_key* dhk)
+{
+    unsigned int init_random = 0;
+    size_t i = 0;
+
+    if(0 == sz || NULL == random_bytes)
+    {
+        fprintf(stderr, "Wrong params for generate_random\n");
+        exit(1);
+    }
+    init_random ^= ((unsigned int)fgetc(dhk->urand) << 8)|fgetc(dhk->urand);
+    srand(init_random);
+    for(i = 0; i < sz; i++)
+    {
+        random_bytes[i] =  rand();
+    }
+}
+
+void print_hex(unsigned char* value, unsigned int len){
+	printf("%s","key exchange:");
+    for(int i=0;i<len;i++)
+        printf("%02x ",value[i]);
+    puts("");
+}
+
+unsigned char* str2hex(char *hexStr){
+    int len=strlen(hexStr)/2;
+    unsigned char * hexvalue=(unsigned char*)malloc(len*sizeof(char));
+    memset(hexvalue,0,len);
+    for(int i=0;i<len;i++){
+        if(hexStr[i*2]<='9'){
+            hexvalue[i]=(hexStr[i*2]-'0')*16;
+        }else
+            hexvalue[i]=(hexStr[i*2]-87)*16;   //a=97
+
+        if(hexStr[i*2+1]<='9'){
+            hexvalue[i]+=(hexStr[i*2+1]-'0');
+        }else
+            hexvalue[i]+=(hexStr[i*2+1]-87);
+    }
+    return hexvalue;
+}
+
+void generate_key(size_t sz, Dh_key* dhk)
+{
+    unsigned char* random_bytes = NULL;
+
+    if(0 == sz || NULL == dhk->private_key)
+    {
+        fprintf(stderr, "Wrong params for generate_key\n");
+        exit(1);
+    }
+    random_bytes = (unsigned char *)malloc(sz*sizeof(unsigned char));
+    if(NULL == random_bytes)
+    {
+        fprintf(stderr, "Failed to allocate random bytes array for the private key\n");
+        exit(1);
+    }
+    generate_random(sz, random_bytes, dhk);
+    mpz_import(dhk->private_key, 1, -1, sz, -1, 0, (const void*)random_bytes);
+    free(random_bytes);
+}
+
+
+void init_prime(size_t sz,Dh_key* dhk)
+{
+    mpz_t tmp;
+    mpz_t x;
+    unsigned char* random_bytes = NULL;
+
+
+    if(0 == sz)
+    {
+        fprintf(stderr, "Wrong params for init_prime\n");
+        exit(1);
+    }
+
+    mpz_init(tmp);
+    mpz_init(x);
+
+    random_bytes = (unsigned char *)malloc(sz*sizeof(unsigned char));
+    if(NULL == random_bytes)
+    {
+        fprintf(stderr, "Failed to allocate random bytes array for the prime number\n");
+        exit(1);
+    }
+    while (1)
+    {
+        generate_random(sz, random_bytes,dhk);
+        random_bytes[sz-1] |= (unsigned char)0x40;
+        random_bytes[0] |= (unsigned char)1;
+
+        mpz_import(tmp, 1, -1, sz, -1, 0, (const void*)random_bytes);
+        while (0 == mpz_probab_prime_p(tmp, 10))
+        {
+            mpz_add_ui(tmp, tmp, 2);
+        }
+        mpz_mul_ui(dhk->prime, tmp, 2);
+        mpz_add_ui(dhk->prime, dhk->prime, 1);
+        if (0 != mpz_probab_prime_p(dhk->prime, 10))
+        {
+            break;
+        }
+    }
+    free(random_bytes);
+
+    mpz_set_ui(dhk->base, (unsigned long)2);
+
+    mpz_clear(tmp);
+    mpz_clear(x);
+}
+
+
+
+void init_numbers(Dh_key* dhk)
+{
+    mpz_init(dhk->key);
+    mpz_init(dhk->prime);
+    mpz_init(dhk->base);
+    mpz_init(dhk->private_key);
+    mpz_init(dhk->public_key);
+}
+
+void clear_numbers(Dh_key* dhk)
+{
+    mpz_clear(dhk->key);
+    mpz_clear(dhk->prime);
+    mpz_clear(dhk->base);
+    mpz_clear(dhk->private_key);
+    mpz_clear(dhk->public_key);
+}