C++ :: Using XOR Encryption?
May 31, 2012
I am currently using a byte encryption in C# which gets decrypted in my C++ client.
It is XOR, but I can't get it to work. Is there anything that Im doing wrong?
I already wrote the C++ XOR in C#, which look pretty much the same.
C#
Code:
public byte[] XOR(byte[] strng, byte[] key) {
int string_len = strng.Length;
int key_length = key.Length;
int i, position;
for (i = 0; i < string_len; i++) {
position = i % key_length;
[code]....
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Jun 15, 2014
what i think i need to create 2 int for the FOR loop to do the encryption but how am i to do it meaning the actual encryption itself what is that i check with?Also i think i need more than just the #include <stdio.h> library due to the file functions that i will need or is C having them built in? Also what is that about the program doing all this from DOS?
Create 2 programs with the names encrypt and decrypt that will encrypt and decrypt files respectively.The encryption and decryption will be done through a command line of DOS and the program should be as follows: encrypt file1 file2 key and decrypt file1 file2 key
Where:
file1 is the source file
file2 is the destination file
key is the word with which we encrypt/decrypt file1
So when the user executes the command encrypt f1 f2 sunnyday the program will create a file with the name f2 which will have the contents of f1 encrypted with the key sunnyday.When the user executes the command decrypt f1 f2 sunnyday the program will create a file with the name f2 which will have the contents of f1 decrypted with the key sunnyday.
If the user gives a wrong key the program will continue to decrypt file1 but since the key is wrong the results will be unexpected.Finally the program must print the corresponding error messages in case of errors for example (There is no file 1).The program is expected to work corectly with not only plain text files but executable (exe) files etc.Also The program must be fully commented.
Note: The way the encryption will work is yours to choose but it is recommended that you encrypt every letter of the file with every letter of the key with the (start to finish and begin) technique meaning that if the key has 8 letters then the first leeter of the file will be encrypted with the first letter of the key, the second letter of the file with the second of the key, ..., the ninth letter of the source file with the first letter of the key, the tenth letter of the source file with the second letter of the key etc.
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Aug 9, 2013
I just want to test AES from openSSL with this 3 modes: with 128,192 and 256 key length but my decrypted text is different from my input and I dont know why. Also, when I pass a huge inputs length (lets say 1024 bytes) my program shows `core dumped`... My input is always the same but it doesnt matter, at least for now. Heres the code:
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <openssl/aes.h>
int main(int argc, char **argv){
[Code] .....
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Apr 28, 2013
I have been assigned a project by my teacher to make a program in c++ which will be able to encrypt a text file, a .docx file or a pdf document !!! Encrypting a text file is easy i have already done that but how do i encrypt a docx file or a pdf file ???
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Aug 5, 2014
Back again with a random bug that I can't seem to track down. My error is in my main.cpp file. I get a C2248 error on line 54, there I'm doing:
t.makeEmpty(t.root)
I know why, because it's a private member...but it should have access in so far as everything is concerned. I double checked my makeEmpty code and it's good to go so far as I can tell. I can't quite iron out where the disconnect is.
V/R
Brad
main.cpp
#include <iostream>
#include <string>
[Code].....
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Oct 29, 2013
We need an AES Encryption/Decryption program in C for college lab (Educational) purpose . So we cannot use any "aes.h" file for this . We need a C program which simulate the purpose of AES
Input : Text (e.g: Anes P.A)
key (e.g:123op)
Output : Cipher Text using AES
I look this functionality done in a website : [URL] ....
Attached Images : AES.jpg (36.4 KB)
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Sep 29, 2013
I am having trouble with an assignment. The assignment consists of a basic encryption and decryption program already written for me, I just have to write the encryption function. What we have to get the program to do is enter an integer and a text, and get the program to increment each letter in the text by the integer given. I did this by using a for loop and incrementing each value in the string by the integer.
However, I still can't get it to decrypt and I need the program to work with only a-z letters (if I increment each letter by 3 and I have the letter Z, it should go to Z+3 = C).
I attached the description of the attachment and below are the codes: The first file does not need to be edited.
Code:
/*******************Programming Assignment 1***************/
/****************Caesar's substitution cipher**************/
/*****************YOU MUST NOT EDIT THIS FILE**************/
/****Substitute alphabets in a string using rotation key***/
/****Leave all other characters unchanged******************/
/****Confirm correct encryption by decrypting**************/
[Code] ......
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Mar 8, 2013
I just started to work on a project which is 'Body Area Network'.
What I need to do is to take data from body with some sensor nodes and send it to mobile which would further send the data to a remote server, and I need to add some security (encryption/decryption) on the data.
So I want to know how to send data from mobile after encrypting it to the server and then decrypt it back(on server side).
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Feb 14, 2012
I have the following function:
Code:
public static void Des(byte[] key, byte[] inBuf, byte[] outBuf) {
if (key.Length != 8 || inBuf.Length != 8 || outBuf.Length != 8) {
throw new Exception("Des: Buffer or key length incorrect.");
}
DESCryptoServiceProvider des = new DESCryptoServiceProvider();
[Code] ....
I do not get the expected output of
Code: { 0x88, 0xBF, 0x0D, 0xB6, 0xD7, 0x0D, 0xEE, 0x56 }
instead I get
Code: { 0xC6, 0x61, 0x8D, 0x63, 0x0B, 0x39, 0x31, 0xB0 } am I doing something wrong?
I've even tried reversing the byte order of the test data, and I don't get the right result. I've tested the same data using C++ with CryptoPP on Linux, and I get the expected result, but I'm porting this code to run on .Net, and this is my main stoppage in the process at the moment.
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Jul 14, 2013
while(!in.eof()) {
in >> ch;
char d = int(ch) + 10;
out << d;
[Code] ....
The first while loop would be to encrypt it, and the second would decrypt it, the decrypting is not giving the original content. For example:
in = Hello
encrypt...
decrypt...
out = Hellooo
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Dec 3, 2013
Code:
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
int encrypt_data(FILE *);
[Code] ....
I am trying encrypt the file "encrypt" when I enter it I get "Error in reading file"
I think its a problem with the fgets() and scanf()...I tried both fgets out and then scanf but I get the same error.
I look in the directory and see that when I enter a file to be encrypted a blank file with a "?" at the end is created in the directory. so I try to encrypt "encrypt" it shows error then creates "encrypt?"
I then tested it by entering a random file name that does not exist
EXAMPLE
Please enter file to be encrypted: fakefilename
Error in reading file.
I look in the directory the non existent file now is listed "fakefilename"
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Jul 22, 2014
I am trying to make a simple program for encrypting a char* with the XOR operator. The code compiles and links perfectly, but I get an Access violation runtime error:
#include <iostream>
#include <cstdlib>
#include <cstdio>
#include <string>
#include <fstream>
using namespace std;
int main(int argc, char** argv) {
[Code] .....
Text that I am inputting:
My username is memberfunction.
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Apr 18, 2014
Write a program to do simple encryption and decryption. Encryption basically means to convert the message into unreadable form. In this assignment, it should be done by replacing each letter of a message with a different letter of the alphabet which is three positions further in the alphabet. Then, all the letters will be reversed. Decryption is the process of converting encrypted message back into its original message. Your program should use the following shifting method.
Note: You must use array.
#include <iostream>
#include <string>
using namespace std;
[Code].....
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Apr 23, 2014
I am writing a program for AES Encryption which is all but done as far as that the program encrypts the text and prints the encrypted text in the command prompt:
void main() {
int a;
unsigned char CipherKey[16] = {0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C};
unsigned char PlainText[16] = {0x32, 0x43, 0xF6, 0xA8, 0x88, 0x5A, 0x30, 0x8D, 0x31, 0x31, 0x98, 0xA2, 0xE0, 0x37, 0x07, 0x34};
for(a=0;a<16;a++)
[Code] ....
Encrypted text output on command prompt = 39 25 84 1d 02 dc 09 fb dc 11 85 97 19 6a 0b 32
However, my project asks to "read blocks of data from a data file". Therefore I need to alter the main function to read the following arrays from a data file.
Unsigned char CipherKey[16] = {0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C};
unsigned char PlainText[16] = {0x32, 0x43, 0xF6, 0xA8, 0x88, 0x5A, 0x30, 0x8D, 0x31, 0x31, 0x98, 0xA2, 0xE0, 0x37, 0x07, 0x34};
Firstly, I don't know how to take each individual part in the data file to store into each byte in the array i.e. 0x2B into CipherKey[0] of the array.
Secondly, How do I deal with the fact that each byte is in hexidecimal? How should my data file look?
this is what my data file Input.dat looks like at the minute:
0x2B, 0x7E, 0x15, 0x16, 0x28, 0xAE, 0xD2, 0xA6, 0xAB, 0xF7, 0x15, 0x88, 0x09, 0xCF, 0x4F, 0x3C
0x32, 0x43, 0xF6, 0xA8, 0x88, 0x5A, 0x30, 0x8D, 0x31, 0x31, 0x98, 0xA2, 0xE0, 0x37, 0x07, 0x34
The first line being the CipherKey array and the second being PlainText. I'm not sure if the '0x' or the commas are required.
I basically want to take the data from a file, store them in arrays in the program itself, encrypt the Input array PlainText and create a new file with the encrypted output array stored in it (I will deal with this part of the program after I get the input file done first).
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