Download Encryption and Decryption Project in c++

Objective

Encryption and decryption of user text massage.

Scope

First of all  user  fulfill the agreement form of this program then  user insert a text massage or include  text massage file (.txt/doc extension )with
encryption key as an input as a result, this program   will encrypt and decrypt this text massage and save it in a file.

Hard ware capability

The hard requirement for this project is  minimum  (Pentium 2) and onwards with 128Mb Ram and 2Mb hard disk.

Analysis

Key generator

We have analyzed the project that we will take a an input (encryption key) from user ,we will convert this key in to10 bit  binary .then we will divide the 10 bit binary key in 5-5 bits .we will do LS-1(LEFT [1bit]) of these 5-5 bits .we will merge and arrange these bits according to the following rule

                        Through this we will get a key(K1)  of 8 bit.

From those 5-5 bits of (LS-1),along with generating the key (K1) ,we will doLS-2(left shift [2bit]) by the  help of above rule (P8) we have  merged(LS-2),we will get key(key2).

Flow chart of key generator

Encryption detail

we will take any  alphabet or integer from the user and will convert  into an 8 bit (IP BINARY),we will divide the this 8 bit binary in to 4-4 bit as left 4bit and right  4bit IP.we will convert right 4bit binary into 8 bit binary and arrange it  according to the following rule.

After applying this rule ,we will add (key 1)with it which we have already generated .we will divide these 8 bits  into 4-4 bits from first 4 bots we will find so and  from remaining 4 bits ,we will find S1.

After  solving S0 and S1 ,we will get 2-2 bit binary  and arrange them through RULE P 4.

Now we will add the left 4 bit IP with this arranged 2-2 bit binary. by using switch function we will repeat this method and use key 2 instead of key 1 as a result of this whole scheme the user ‘s given massage will encrypt.

Decryption detail

All method is same as encryption but here we will use sub key2.

How to run this program

• For Encryption

Follow the following steps.

• Right click on the file encryption and decryption program file and click “RUN”.
• Press “ENTER” to continue.
• Read all the instruction carefully if you fallow this instruction press”1” .
• Here two option are available either user insert directly massage or inert massage file (.txt .doc extension) press “2” .
• There are two option for encrypt  and decrypt first time user try to encrypt press”1”.
• Now user insert text massage with encryption key. Be alert your massage words must equal to your insert key and press enter to continue.
• In this step program will ask to user to  create  two  files(.txt/doc extension)  in which your key and your encryption result  will save .
• As a result key and output of the encryption will save in following two files.
• When the above mentioned file will create ,at a same time   program will show user txt massage in encrypt form.

• For Decryption

• First three step of decryption same as encryption which are mentioned as above.
• In this step user will include encrypted file for decryption press “1”
• When step 02 program ask to user what do you want either encryption or decryption ,while we are going for decryption and  we will press “2”.
• Now we will insert the names of the encrypted file and key file  i-e (out.txt  & key.txt) .
• In this step user create third file in which the result of decryption will save.

         Decryption has completed………

Coding

#include<iostream> #include<fstream> #include<conio.h> using namespace std; void binary(int num,int bin[]) { int loop=9; while(loop>=0) { bin[loop]=num%2; num=num/2; loop--; } } void p10_arrange(int bin[],int p10[]) { p10[0]=bin[2]; p10[1]=bin[4]; p10[2]=bin[1]; p10[3]=bin[6]; p10[4]=bin[3]; p10[5]=bin[9]; p10[6]=bin[0]; p10[7]=bin[8]; p10[8]=bin[7]; p10[9]=bin[5]; } void LS1(int p10[],int left_LS1[],int right_LS1[]) { left_LS1[0]=p10[1]; left_LS1[1]=p10[2]; left_LS1[2]=p10[3]; left_LS1[3]=p10[4]; left_LS1[4]=p10[0]; right_LS1[0]=p10[6]; right_LS1[1]=p10[7]; right_LS1[2]=p10[8]; right_LS1[3]=p10[9]; right_LS1[4]=p10[5]; } void p8(int left_LS1[],int right_LS1[],int subkey1[]) { subkey1[0]=right_LS1[0]; subkey1[1]=left_LS1[2]; subkey1[2]=right_LS1[1]; subkey1[3]=left_LS1[3]; subkey1[4]=right_LS1[2]; subkey1[5]=left_LS1[4]; subkey1[6]=right_LS1[4]; subkey1[7]=right_LS1[3]; } void LS2(int left_LS1[],int right_LS1[],int left_LS2[],int right_LS2[]) { left_LS2[0]=left_LS1[2]; left_LS2[1]=left_LS1[3]; left_LS2[2]=left_LS1[4]; left_LS2[3]=left_LS1[0]; left_LS2[4]=left_LS1[1]; right_LS2[0]=right_LS1[2]; right_LS2[1]=right_LS1[3]; right_LS2[2]=right_LS1[4]; right_LS2[3]=right_LS1[0]; right_LS2[4]=right_LS1[1]; } void key_generator(int num,int subkey1[],int subkey2[]) { int bin[10]; binary(num,bin); ///////////////// P10 ////////////////////////// int p10[10]; p10_arrange(bin,p10); ///////////////// LS-1 //////////////////// int left_LS1[5],right_LS1[5]; LS1(p10,left_LS1,right_LS1); ////////////////// p8 ////////////////////////// p8(left_LS1,right_LS1,subkey1); /////////////// LS2 //////////////////////// int left_LS2[5],right_LS2[5]; LS2(left_LS1,right_LS1,left_LS2,right_LS2); ////////////////// p8 //////////////////////// p8(left_LS2,right_LS2,subkey2); } ////////////////////////////////// all above functions are about key generat ////////////////////////// void IP(int bin[],int ip_arrange[]) { ip_arrange[0]=bin[3]; ip_arrange[1]=bin[7]; ip_arrange[2]=bin[4]; ip_arrange[3]=bin[2]; ip_arrange[4]=bin[5]; ip_arrange[5]=bin[9]; ip_arrange[6]=bin[6]; ip_arrange[7]=bin[8]; } void seperate(int ip_arrange[],int left_ip[],int right_ip[]) { left_ip[0]=ip_arrange[0]; left_ip[1]=ip_arrange[1]; left_ip[2]=ip_arrange[2]; left_ip[3]=ip_arrange[3]; right_ip[0]=ip_arrange[4]; right_ip[1]=ip_arrange[5]; right_ip[2]=ip_arrange[6]; right_ip[3]=ip_arrange[7]; } void FP_arrange(int right_ip[],int fp[]) { fp[0]=right_ip[3]; fp[1]=right_ip[0]; fp[2]=right_ip[1]; fp[3]=right_ip[2]; fp[4]=right_ip[1]; fp[5]=right_ip[2]; fp[6]=right_ip[3]; fp[7]=right_ip[0]; } void Zor(int fp[],int subkey1[],int left_zor[4],int right_zor[4]) { if(fp[3]==subkey1[0]) left_zor[0]=0; else if (fp[3]!=subkey1[0]) left_zor[0]=1; if(fp[0]==subkey1[1]) left_zor[1]=0; else if (fp[0]!=subkey1[1]) left_zor[1]=1; if(fp[1]==subkey1[2]) left_zor[2]=0; else if (fp[1]!=subkey1[2]) left_zor[2]=1; if(fp[2]==subkey1[3]) left_zor[3]=0; else if (fp[2]!=subkey1[3]) left_zor[3]=1; ////////////////////////////// right_zor /////////////////////////////////// if(fp[1]==subkey1[4]) right_zor[0]=0; else if (fp[1]!=subkey1[4]) right_zor[0]=1; if(fp[2]==subkey1[5]) right_zor[1]=0; else if (fp[2]!=subkey1[5]) right_zor[1]=1; if(fp[3]==subkey1[6]) right_zor[2]=0; else if (fp[3]!=subkey1[6]) right_zor[2]=1; if(fp[0]==subkey1[7]) right_zor[3]=0; else if (fp[0]!=subkey1[7]) right_zor[3]=1; } void S_box(int left_zor[],int right_zor[],int s0[] ,int s1[] ) { int s_box0[4][4]={{1,0,3,2},{3,2,1,0},{0,2,1,3},{3,1,3,2}}; int row=(left_zor[0]*2)+(left_zor[3]*1),col=(left_zor[1]*2)+(left_zor[2]*1); int num; //////////////// for s0 //////////////////// num=s_box0[row][col]; for(int l=1;l>=0;l--) { s0[l]=num%2; num=num/2; } //////////////// for s1 ///////////////////////////// int s_box1[4][4]={{0,1,2,3},{2,0,1,3},{3,0,1,0},{2,1,0,3}}; int row1=(right_zor[0]*2)+(right_zor[3]*1),col1=(right_zor[1]*2)+(right_zor[2]*1); num=s_box1[row1][col1]; for(int l=1;l>=0;l--) { s1[l]=num%2; num=num/2; } } void P4_arrange(int s0[],int s1[],int p4[]) { p4[0]=s0[1]; p4[1]=s1[1]; p4[2]=s1[0]; p4[3]=s0[0]; } void P4_zor(int left_ip[],int p4[],int sw_right_ip[]) { for(int l=0;l<4;l++) { if(left_ip[l]==p4[l]) sw_right_ip[l]=0; if(left_ip[l]!=p4[l]) sw_right_ip[l]=1; } } void Ip_invers(int sw_zor[],int sw_right_ip[],int ip_inv[]) { ip_inv[0]=sw_zor[3]; ip_inv[1]=sw_zor[0]; ip_inv[2]=sw_zor[2]; ip_inv[3]=sw_right_ip[0]; ip_inv[4]=sw_right_ip[2]; ip_inv[5]=sw_zor[1]; ip_inv[6]=sw_right_ip[3]; ip_inv[7]=sw_right_ip[1]; } int E(int leter_num,int key_num ) { int subkey1[8],subkey2[8]; key_generator(key_num,subkey1,subkey2); int bin[10]; binary(leter_num,bin); ///////////////////////////// IP /////////////////////// int ip_arrange[8]; IP(bin,ip_arrange); ////////////////// left_ip and right_ip /////////////////////////// int left_ip[4],right_ip[4]; seperate(ip_arrange,left_ip,right_ip); ////////////////// F/P ////////////////////////////////////////// int fp[8]; FP_arrange(right_ip,fp); /////////////////////// Zor ////////////////////////////// int left_zor[4],right_zor[4]; Zor(fp,subkey1,left_zor,right_zor); ///////////////////// s box /////////////////////////////////////// int s0[2],s1[2]; S_box(left_zor,right_zor,s0,s1); ///////////////////// P4 //////////////////////////////////// int p4[4]; P4_arrange(s0,s1,p4); ////////////////////// p4_zor //////////////////////////// int sw_right_ip[4]; P4_zor(left_ip,p4,sw_right_ip); ///////////////////////// switch fucntion portion //////////////////////////////////////////// int sw_fp[8]; FP_arrange(sw_right_ip,sw_fp); ///////////////////////////// sub key2 and sw_fp zor ////////////////////////////////// int sw_left_zor[4],sw_right_zor[4]; Zor(sw_fp,subkey2,sw_left_zor,sw_right_zor); ////////////////////////////////// sw s-box ///////////////////////////// int sw_s0[2],sw_s1[2]; S_box(sw_left_zor,sw_right_zor,sw_s0,sw_s1); ////////////////////// sw p4 /////////////////////////////////////// int sw_p4[4]; P4_arrange(sw_s0,sw_s1,sw_p4); ///////////////////////// right_ip and sw_p4 zor ////////////////////////////// int sw_zor[4]; P4_zor(right_ip,sw_p4,sw_zor); ////////////////////////// IP invers //////////////////////////////// int ip_inv[8]; Ip_invers(sw_zor,sw_right_ip,ip_inv); int sum; sum=(ip_inv[0]*128)+(ip_inv[1]*64)+(ip_inv[2]*32)+(ip_inv[3]*16)+(ip_inv[4]*8)+(ip_inv[5]*4)+(ip_inv[6]*2)+(ip_inv[7]*1); return(sum); } int D(int leter_num,int key_num ) { int subkey1[8],subkey2[8]; key_generator(key_num,subkey1,subkey2); int bin[10]; binary(leter_num,bin); ///////////////////////////// IP /////////////////////// int ip_arrange[8]; IP(bin,ip_arrange); ////////////////// left_ip and right_ip /////////////////////////// int left_ip[4],right_ip[4]; seperate(ip_arrange,left_ip,right_ip); ////////////////// F/P ////////////////////////////////////////// int fp[8]; FP_arrange(right_ip,fp); /////////////////////// Zor ////////////////////////////// int left_zor[4],right_zor[4]; Zor(fp,subkey2,left_zor,right_zor); ///////////////////// s box /////////////////////////////////////// int s0[2],s1[2]; S_box(left_zor,right_zor,s0,s1); ///////////////////// P4 //////////////////////////////////// int p4[4]; P4_arrange(s0,s1,p4); ////////////////////// p4_zor //////////////////////////// int sw_right_ip[4]; P4_zor(left_ip,p4,sw_right_ip); ///////////////////////// switch fucntion portion //////////////////////////////////////////// int sw_fp[8]; FP_arrange(sw_right_ip,sw_fp); ///////////////////////////// sub key2 and sw_fp zor ////////////////////////////////// int sw_left_zor[4],sw_right_zor[4]; Zor(sw_fp,subkey1,sw_left_zor,sw_right_zor); ////////////////////////////////// sw s-box ///////////////////////////// int sw_s0[2],sw_s1[2]; S_box(sw_left_zor,sw_right_zor,sw_s0,sw_s1); ////////////////////// sw p4 /////////////////////////////////////// int sw_p4[4]; P4_arrange(sw_s0,sw_s1,sw_p4); ///////////////////////// right_ip and sw_p4 zor ////////////////////////////// int sw_zor[4]; P4_zor(right_ip,sw_p4,sw_zor); ////////////////////////// IP invers //////////////////////////////// int ip_inv[8]; Ip_invers(sw_zor,sw_right_ip,ip_inv); int sum; sum=(ip_inv[0]*128)+(ip_inv[1]*64)+(ip_inv[2]*32)+(ip_inv[3]*16)+(ip_inv[4]*8)+(ip_inv[5]*4)+(ip_inv[6]*2)+(ip_inv[7]*1); return(sum); } ////////////////////////////program Body////////////////////////////// void get_file_data(char message_file[],char key_file[],char user_message[],char user_key[]) { //////////////// message file ///////////////////////////// fstream myline(message_file,ios::out | ios::app); myline.close(); int loop=0; fstream line(message_file,ios::in); if(!line) cout<<"There is some error so that's way file can not be open .\n\n"; else { while(!line.eof()) { user_message[loop]=line.get(); loop++; } } line.close(); ////////////////////////// key file ///////////////////////////////////// fstream mykey(key_file,ios::out | ios::app); mykey.close(); loop=0; fstream key(key_file,ios::in); if(!key) cout<<"There is some error so that's way file can not be open .\n\n"; else { while(!key.eof()) { user_key[loop]=key.get(); loop++; } } key.close(); } int E_and_D_choice() { char cchoice; int ichoice; do { system("cls"); cout<<"(1) Encrypt my message.\n\n"; cout<<"(2) Decrypt my message.\n\n"; cout<<"\n\nEnter your choice :"; cin>>cchoice; ichoice=cchoice; if((ichoice!=49)&&(ichoice!=50)) { cout<<"\n\nInvalid choice! Press enter and Try angain."; getch(); } } while((ichoice!=49)&&(ichoice!=50)); return(ichoice); } void key_store(char user_key[]) { char key_file[500]; int loop=0; cout<<"Type your file name inwhich your key will be store :"; cin.getline(key_file,500); fstream myfile(key_file,ios::out | ios:: app); while(user_key[loop]!=-52) { myfile<<user_key[loop]; loop++; } myfile.close(); } void Encryption_and_Decryption(char user_message[],char user_key[],char ED_choice) { ///////////////////////////// user output data save in file ///////////////////////////// system("cls"); char output_file[500]; system("cls"); cout<<"Type your file name inwhic your output data will be store :"; cin.getline(output_file,500); system("cls"); int line; int key; char output[99999]; int loop=0; char ch; system("cls"); if(ED_choice==49) { cout<<" Encrypt message \n\n\n\n"; while((user_message[loop]!='\0')&&(user_key[loop]!='\0')&&(user_message[loop]!=-52)&&(user_key[loop]!=-52)) { line=user_message[loop]; key=user_key[loop]; ch=E(line,key); output[loop]=ch; fstream save_file(output_file,ios::out | ios::app); save_file<<ch; save_file.close(); cout<<ch; loop++; } } loop=0; if(ED_choice==50) { system("cls"); cout<<" Decrypt message \n\n\n\n"; while((user_message[loop]!='\0')&&(user_key[loop]!='\0')&&(user_message[loop]!=-52)&&(user_key[loop]!=-52)) { line=user_message[loop]; key=user_key[loop]; if(line<0) line=line+256; ch=D(line,key); fstream key(output_file,ios::out | ios::app); key<<ch; key.close(); cout<<ch; loop++; } } getch(); cout<<"\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n"; } void message_and_key(int ichoice) { char user_message[99999]; char user_key[99999]; char message_file[500]; char key_file[500]; //////////////////////////// encryption and decryption choice //////////////////// int ED_choice; ED_choice=E_and_D_choice(); // user encrypt or decrypt choice if(ichoice==49) { system("cls"); cout<<"Enter your message file name :"; cin.sync(); cin.getline(message_file,500); cout<<"\n\n"; cout<<"Enter your key file name :"; cin.getline(key_file,500); get_file_data(message_file,key_file,user_message,user_key); // function calling Encryption_and_Decryption(user_message,user_key,ED_choice); } else if(ichoice==50) { system("cls"); cout<<" Type your message\n\n"; cin.sync(); cin.getline(user_message,99999); cout<<" Type your key\n\n"; cin.getline(user_key,99999); system("cls"); key_store(user_key); // function for save user key in a file; Encryption_and_Decryption(user_message,user_key,ED_choice); } } void file_choice() { system("cls"); char cchoice; int ichoice; do { system("cls"); cout<<"\n\nYou have two choices, you can include your text files inwhice your message and key saved otherwise your will type your message and key for encryption and decryption. \n\n\n\n\n\n"; cout<<"(1) Include my files for taking message and key.\n\n"; cout<<"(2) Don't include my files, I will type my message and key.\n\n"; cout<<"\n\nEnter your choice:"; cin>>cchoice; ichoice=cchoice; if((ichoice!=49)&&(ichoice!=50)) { cout<<"\n\nInvalid choice! Press enter and Try angain."; getch(); } } while((ichoice!=49)&&(ichoice!=50)); //////////////// funciton calling //////////////////////////// message_and_key(ichoice); // function calling } void run() { char cchoice; int ichoice; do { system("cls"); cout<<" INSTRUCTIONS\n\n\n\n"; cout<<"Read the software instructions carefully and follow them otherwise software willnot responsible for anything wrong.\n\n\n\n"; cout<<" (1) Use only word and txt file, for example \"My file.doc\" or \"My file.txt\".\n\n"; cout<<" (2) Type file name with proper extension like \"file.txt\".\n\n"; cout<<" (3) Message and key file must be same format and extension.\n\n"; cout<<" (4) Message and key character length must be equal.\n\n"; cout<<" (5) software will encrypt or decrypt only thoes characters which ASCII number \n between 0 to 256.These exe numbers and there characters are provided with software, file name is \"ASCIIs codes\".\n\n"; cout<<" (6) Your message should be under 90000 characters and also key should be \n under 90000 characters.\n\n"; cout<<" (7) Save your message file and key file in this floder where your software is store and then use these message file and key file.\n\n"; cout<<” (8) Do not use copy past material in your message and key files.\n\n”; cout<<"\n\n(1) Yes , I will fallow these instructions . \n\n(2) No , I will not fallo these instructions\n\n"; cout<<"\n\n"; cout<<"Enter your choice :"; cin>>cchoice; ichoice=cchoice; if(ichoice==49) { system("cls"); file_choice(); } else if(ichoice==50) { system("cls"); cout<<"Ok ,No problem Press enter for exit "; getch(); cout<<"\n\n"; } else { cout<<"\n\nInvalid choice! Press enter and Try angain."; getch(); } } while((ichoice!=49)&&(ichoice!=50)); } void project_name() { cout<<"\n\n\n\n\n\n"; cout<<" ##### ## # ##### ##### # # ###### ####### ##### ##### ## #\n"; cout<<" # # # # # # # # # # # # # # # # # #\n"; cout<<" ##### # # # # ##### ###### ###### # # # # # # # \n"; cout<<" # # # # # # # # # # # # # # # #\n"; cout<<" ##### # ## ##### # # ###### # # ##### ##### # ##\n"; cout<<"\n\n\n\n\n\n"; cout<<"\t\t\t ###### ## # ##### \n"; cout<<"\t\t\t # # # # # # # \n"; cout<<"\t\t\t ###### # # # # # \n"; cout<<"\t\t\t # # # # # # # \n"; cout<<"\t\t\t # # # ## ##### \n"; cout<<"\n\n\n\n\n\n"; cout<<" ##### ##### ##### ##### # # ###### ####### ##### ##### ## #\n"; cout<<" # # # # # # # # # # # # # # # # #\n"; cout<<" # # ##### # ##### ###### ###### # # # # # # # \n"; cout<<" # # # # # # # # # # # # # # #\n"; cout<<" ##### ##### ##### # # ###### # # ##### ##### # ##\n"; cout<<"\n\n\n\n\n\n\n\n\n\n\n\n\n\n\nAll CopyRights are reserved."; getch(); } void main() { project_name(); run(); // agreeement function }