Microsoft .Net framework provided cryptography class object, These objects are usefully for encryption/decryption/hashing on sensitivity data files.(File transfers).
In the FTP world, Every organization transfer files to third party in a secure way using sftp protocols with pgp /custom encryption on data files.
Why Hash?
In the FTP world, Every organization transfer files to third party in a secure way using sftp protocols with pgp /custom encryption on data files.
Why Hash?
- Hash plays a role in security systems where they're used to ensure that transmitted data files have not been tampered by hacker.
- The sender generates a hash of the data file, encrypts it, and sends it with the Data file itself.
- The recipient then decrypts both the Data File and the hash,
- Recipient produces another hash from the received data file and compare sender hash and recipient generated hash
- If they're the same, there is a very high probability that the message was transmitted intact.
For demo purpose I have created a console application in C#.net using System.Security.Cryptography class and Tsql scripts in SQL Server 2014
Algorithm : SHA256
Demo
Step1:
A text file is created under C:\Hari\hari.txt and added "I am a good boy" as text.
Process generated hash on hari.txt file
-- hash value with original value text ("I am a good boy")
F8C5F1FF1157F91FF64D1EFCA65B0A0318E84A21F72C3A6F5571E186A1D49D34
Step2:
next I opened file C:\Hari\hari.txt and modified text inside "I am good boy, I am from Jamaica".
process generated hash on hari.txt file
-- hash value is changed when i modified a text file.
EC90609F3C3A58CA5DD499EB6833C4D66DA60E216A5A67BD9AAAFEB7133F6969
Step3:
when I compare both hash values, They did not match and possible tamper in the file.
the following code will give you an idea, How to generate hash.
Please find C# demo code here
using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Security.Cryptography;
using System.IO;
namespace ConsoleApplication1
{
class Program
{
static void Main(string[] args)
{
//hash some test file
string path = @"C:\hari\hari.txt";
string checksumMd5 = GetChecksum(path, Algorithms.MD5);
string checksumSha1 = GetChecksum(path, Algorithms.SHA1);
string checksumSha256 = GetChecksum(path, Algorithms.SHA256);
string checksumSha384 = GetChecksum(path, Algorithms.SHA384);
string checksumSha512 = GetChecksum(path, Algorithms.SHA512);
string checksumRipemd160 = GetChecksum(path, Algorithms.RIPEMD160);
//print buffer value.
Console.Write(checksumSha256);
//wait for userinput
Console.ReadKey();
}
// create algorithm class
public static class Algorithms
{
public static readonly HashAlgorithm MD5 = new MD5CryptoServiceProvider();
public static readonly HashAlgorithm SHA1 = new SHA1Managed();
public static readonly HashAlgorithm SHA256 = new SHA256Managed();
public static readonly HashAlgorithm SHA384 = new SHA384Managed();
public static readonly HashAlgorithm SHA512 = new SHA512Managed();
public static readonly HashAlgorithm RIPEMD160 = new RIPEMD160Managed();
}
// hashing file by reading data in the file using stream readers
public static string GetChecksum(string filePath, HashAlgorithm algorithm)
{
using (var stream = new BufferedStream(File.OpenRead(filePath), 100000))
{
byte[] hash = algorithm.ComputeHash(stream);
return BitConverter.ToString(hash).Replace("-", String.Empty);
}
}
}
}
T sql script in Sql sever 2014.
I used Binary_check sum and Hash functions.
