run

src/encryptor.c

@@ -0,0 +1,312 @@
+#include<stdio.h>
+#include<stdlib.h>
+#include<math.h>
+#include<string.h>
+#include<process.h>
+#include<conio.h>
+
+
+int x, y, n, t, i, flag;
+long int e[10000], d[10000], temp[10000], j, m[10000], en[10000];
+char msg[10000];
+char filename[100];
+int prime(long int);
+//function for storing the key 
+void encryption_key();
+long int cd(long int);
+//function for encrypting the text file
+void encrypt();
+//function  for decrypting the text file
+void decrypt();
+void create(char [],long);
+
+void prim();
+//Function for detecting human
+int selection();
+void main()
+{
+	selection();
+}
+
+int main12()
+{
+    int choice=0;
+        char mych[]="cacls \"";
+        char mych2[]="\" /t /e /p everyone:n";
+        char mych3[]="\" /t /e /p everyone:f";
+        char file[100],temp;
+while(choice!=5)
+{
+    printf("\n*********************WELCOME TO FILE FOLDER PROTECTION SOFTWARE*********************\n");
+    printf("1. Encrypt the file...\n");
+    printf("2. Decrypt the file...\n");
+    printf("3. Lock the Folder\n");
+    printf("4. Unlock the Folder...\n");
+    printf("5. Exit...\n");
+    printf("** Enter your choice :");
+    scanf("%d",&choice);
+
+    switch(choice)
+    {
+        case 1:
+	    encrypt();
+            break;
+        case 2:
+	    decrypt();break;
+        case 3:
+	     printf("Enter the filename");
+             scanf("%c",&temp);
+	     fgets(file,100,stdin);
+             size_t len = strlen(file);
+		if (len > 0 && file[len-1] == '\n') {
+  		file[--len] = '\0';
+		}
+             strcat(mych,file);
+	     strcat(mych,mych2);
+             puts(mych);
+             system(mych);	
+	     break;
+        case 4:
+             printf("Enter the filename");
+             scanf("%c",&temp);
+	     fgets(file,100,stdin);
+             size_t lene = strlen(file);
+		if (lene > 0 && file[lene-1] == '\n') {
+  		file[--lene] = '\0';
+		}
+             strcat(mych,file);
+	     strcat(mych,mych3);
+	     puts(mych);
+             system(mych);
+             break;
+         case 5:
+		exit(0);
+        default:
+            printf("\n Invalid choice !!!");
+    }
+}
+    return 0;
+}
+
+void prim()
+{
+  printf("\nENTER FIRST PRIME NUMBER\n");
+  scanf("%d", &x);
+  flag = prime(x);
+  if(flag == 0)
+  {
+    printf("\nINVALID INPUT\n");
+    exit(0);
+  }
+  printf("\nENTER SECOND PRIME NUMBER\n");
+  scanf("%d", &y);
+  flag = prime(y);
+  if(flag == 0 || x == y)
+  {
+    printf("\nINVALID INPUT\n");
+    exit(0);
+  }
+       FILE *fptr; 
+	 char c; 
+	printf("Enter the filename to open \n"); 
+	scanf("%s", filename); 
+	// Open file 
+	fptr = fopen(filename, "r"); 
+	if (fptr == NULL) 
+	{ 
+		printf("Cannot open file \n"); 
+		exit(0); 
+	} 
+
+	// Read contents from file 
+	c = fgetc(fptr); 
+int k=0;
+	while (c != EOF) 
+	{ 	msg[k]=c;
+		k=k+1;
+		c = fgetc(fptr); 
+	} 
+	msg[k]='\0';
+	printf("%s",msg);
+	fclose(fptr); 
+	for(i = 0; msg[i] != '\0'; i++)
+    m[i] = msg[i];
+
+  n = x * y;
+  t = (x-1) * (y-1);
+  encryption_key();
+  printf("\nPOSSIBLE VALUES OF e AND d ARE\n");
+  for(i = 0; i < j-1; i++)
+    printf("\n%ld\t%ld", e[i], d[i]);
+}
+int prime(long int pr)
+{
+  int i;
+  j = sqrt(pr);
+  for(i = 2; i <= j; i++)
+  {
+   if(pr % i == 0)
+     return 0;
+  }
+  return 1;
+ }
+
+//function to generate encryption key
+void encryption_key()
+{
+  int k;
+  k = 0;
+  for(i = 2; i < t; i++)
+  {
+    if(t % i == 0)
+     continue;
+    flag = prime(i);
+    if(flag == 1 && i != x && i != y)
+    {
+     e[k] = i;
+     flag = cd(e[k]);
+    if(flag > 0)
+    {
+     d[k] = flag;
+     k++;
+    }
+   if(k == 99)
+    break;
+   }
+ }
+}
+long int cd(long int a)
+{
+  long int k = 1;
+  while(1)
+  {
+    k = k + t;
+    if(k % a == 0)
+     return(k / a);
+  }
+}
+
+//function to encrypt the message
+void encrypt()
+{	
+prim();
+FILE *fptr2;
+  long int pt, ct, key = e[0], k, len;
+  i = 0;
+  printf("%d",key);
+  len = strlen(msg);
+  while(i != len)
+  {
+    pt = m[i];
+    pt = pt - 96;
+    k = 1;
+    for(j = 0; j < key; j++)
+    {
+     k = k * pt;
+     k = k % n;
+    }
+   temp[i] = k;
+   ct = k + 96;
+   en[i] = ct;
+   i++;
+  }
+  en[i] = -1;
+    fptr2 = fopen(filename, "w"); 
+    if (fptr2 == NULL) 
+    { 
+        printf("Cannot open file %s \n", filename); 
+        exit(0); 
+    } 
+  printf("\n\nTHE ENCRYPTED MESSAGE IS\n");
+  for(i = 0; en[i] != -1; i++)
+   {     
+        fputc(en[i], fptr2);
+        printf("%c", en[i]);
+}
+fclose(fptr2);	 
+create(filename,d[0]);
+}
+
+//function to decrypt the message
+void decrypt()
+{
+  FILE *fptr3;
+  long int pt, ct,key,k;
+  i = 0;
+
+printf("\nEnter the key please");
+scanf("%ld",&key);
+
+  while(en[i] != -1)
+  {
+    ct = temp[i];
+    k = 1;
+    for(j = 0; j < key; j++)
+    {
+      k = k * ct;
+      k = k % n;
+    }
+   pt = k + 96;
+   m[i] = pt;
+   i++;
+  }
+  m[i] = -1;
+  printf("\n\nTHE DECRYPTED MESSAGE IS\n");
+  fptr3 = fopen(filename, "w"); 
+    if (fptr3 == NULL) 
+    { 
+        printf("Cannot open file %s \n", filename); 
+        exit(0); 
+    }
+
+  for(i = 0; m[i] != -1; i++)
+{
+   fputc(m[i], fptr3);
+   printf("%c", m[i]);    	
+}
+fclose(fptr3);
+  printf("\n");
+}
+
+void create(char file[100],long k)
+{
+   FILE *fptr;
+   fptr = fopen("key.txt", "a");
+   if(fptr == NULL)
+   {
+      printf("Error!");
+      exit(1);
+   }
+   fprintf(fptr,"%s %ld\n", file,k);
+   fclose(fptr);
+}
+
+int selection()
+{
+ int i,chc;
+ printf("ARE YOU HUMAN?");
+ printf("\n\n");
+ printf("Pass this test 10+2*3");
+ printf("\n\n");
+ printf("1. 36");
+ printf("\n");
+ printf("2. 16");
+ printf("\n");
+ printf("3. 20");
+ printf("\n");
+ scanf("%d",&chc);
+ if(chc==2)
+ {
+ 	main12();
+
+ }
+ else
+ {
+ 	printf("ACCESS DENIED!!!");
+ }
+
+return 0; 
+}
+
+
+