在C＃上获取文件的SHA1二进制base64哈希

Question

I am thinking on creating a program on C# to get the SHA1 binary base64 hash of a series of very large files.

Right now I can accomplish that by running this instruction on OpenSSL:

openssl sha1 -binary FILENAME | openssl base64

however I haven´t found references for the "binary" and "base64" parts to obtain the same result with C#.

Is it possible? Maybe call openssl inside C#?

Thank you.

Answer 1

You need to use the Convert.ToBase64String method and the System.IO namespace to read binary:

string GetBase64EncodedSHA1Hash(string filename)
{
    using (FileStream fs = new FileStream(filename, FileMode.Open, FileAccess.Read, FileShare.Read))
    using (SHA1Managed sha1 = new SHA1Managed())
    {
        return Convert.ToBase64String(sha1.ComputeHash(fs));
    }
}

Answer 2

The easiest way to do this is Get-FileHash which has been available since PS 4.0

$ echo "Hello world" >1.tm
$
$ Get-FileHash 1.tm

Algorithm       Hash                                                                   
Path
---------       ----                                                                   ----
SHA256          B995A2FAFFB3F27C632CE037BDB2ADB04EC3E578D0FA794BA50CFC16F0F219BF       
C:\scratch\1.tm


$