This article introduces a C# function that can calculate the MD5 value of a file and can be used for validity verification after file transfer.
We know that it is the most common MD5 application to get a 32-bit string by hashing a string and saving it as a password. I don’t know if you have noticed that in some places where files are downloaded online, the MD5 check value is indicated next to it, which is also a 32-bit sixteen-type string. How to use this string? This is the MD5 encryption of the file.
After we download a file from the Internet, we can calculate the MD5 value of the file and compare it with the MD5 value published online. The results are consistent, which means there is no problem with the file. If the results are inconsistent, there are two possibilities: one is that the file is corrupted and cannot be used; the other is that the file is replaced by someone. When downloading an exe file, you should pay special attention to it. If you download a file that has been replaced by someone, it is quite dangerous. This file may be implanted into a *.
So how should we calculate the MD5 value of the file? Brother Hong gave a C# source code. Friends who are interested can refer to it. Note that the following code must contain a namespace.
/// <summary>
/// MD5 verification of calculation files
/// </summary>
/// <param name="fileName"></param>
/// <returns></returns>
public static string GetMD5HashFromFile(string fileName)
{
try
{
FileStream file = new FileStream(fileName, );
.MD5 md5 = new .MD5CryptoServiceProvider();
byte[] retVal = (file);
();
StringBuilder sb = new StringBuilder();
for (int i = 0; i < ; i++)
{
(retVal[i].ToString("x2"));
}
return ();
}
catch (Exception ex)
{
throw new Exception("GetMD5HashFromFile() fail,error:" + );
}
}
As you can see, the above C# code mainly creates the .MD5 class and uses its ComputeHash method. Then convert the byte array into a hexadecimal string to return.
You can use the above main function to write a mini program to calculate the MD value of a file by yourself in C#.
This article introduces so much about the code for calculating the MD5 value of C# file. I hope it will be helpful to you. Thank you!