How to get the same MD5 string in Java as in C#

Question

I have code in C# which produces MD5 encoded byte[] from String and then this byte[] is converted to String. The C# code is

byte[] valueBytes = (new UnicodeEncoding()).GetBytes(value);
byte[] newHash = (new MD5CryptoServiceProvider()).ComputeHash(valueBytes);

I need to get the same result in Java. I'm trying to do this

Charset utf16 = Charset.forName("UTF-16");
return new String(DigestUtils.md5(value.getBytes(utf16)), utf16);

The code is using Apache Commons Codec library for MD5 calculations. I'm using UTF16 charset because I've read in other SO questions that C#'s UnicodeEncoding uses it by default.

So the code snippets look like they do the same thing, but when I'm passing the string byndyusoft2014, C# gives me hV7u6mQYRgBXXF9jOWWYJg== and Java gives me ﹡둛뭶魙ꇥ늺ꢑ. I've tried UTF16LE and UTF16BE as charsets with no luck.

Has anyone idea about what I'm doing wrong?

C# gives me hV7u6mQYRgBXXF9jOWWYJg== No your code returns byte array. You convert it somewhere to base64 string. Do the same in hava too — L.B
– L.B, Commented Aug 28, 2017 at 15:10
What is byndyusoft2014? You shouldn't create a string out of the MD5 hash value bytes directly. You can use the md5Hex() method or the Base64 class to get a string representation for the bytes. And you should use the same type of string representation for the hash bytes in both languages. — vanje
– vanje, Commented Aug 28, 2017 at 15:23

dabaicai · Accepted Answer · 2017-08-28 15:52:01Z

1

I think because of the java decode string to byte[] with utf-8,but the C# is not.So the java and C# encode the different byte array,and then get the different result.You can decode the string to byte[] at c# with utf-8,and see the result.Like following code:

UTF8Encoding utf8 = new UTF8Encoding();
byte[] bytes=utf8.GetBytes("byndyusoft2014");
byte[] en=(new MD5CryptoServiceProvider()).ComputeHash(bytes);
Console.WriteLine(Convert.ToBase64String(en));

and the java code:

    byte[] en = DigestUtils.md5Digest("byndyusoft2014".getBytes());
    byte[] base64 = Base64Utils.encode(en);
    System.out.println(new String(base64));

Of course,in your description,the result of C# like be encoded with base64,so the java should encode the byte array with base64. The result of them is same as swPvmbGDI1GbPKQwL9knjQ==

The DigestUtils and Base64Utils is some implementation of MD5 and BAS64 in spring library

edited Aug 28, 2017 at 15:52

answered Aug 28, 2017 at 15:46

dabaicai

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Fyodor Sherstobitov Over a year ago

Thank you for the hint with Base64. It solved the problem.

Fyodor Sherstobitov · Accepted Answer · 2017-08-28 16:19:21Z

0

As it turned out, the main difference was not presented in my original code snippet - it was convertation from MD5 encoded byte[] to String. You need to use Base64 to get final result. This is the working code snippet in Java

Charset utf16 = Charset.forName("UTF-16LE");
return new String(Base64.encodeBase64(DigestUtils.md5(value.getBytes(utf16))));

With this code I get the same result as with C#. Thank you all for good hints!

answered Aug 28, 2017 at 16:19

Fyodor Sherstobitov

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