c# - How to convert an MD5 hash to a string and use it as a file name

Question

I am taking the MD5 hash of an image file and I want to use the hash as a filename.

How do I convert the hash to a string that is valid filename?

EDIT: toString() just gives "System.Byte[]"

Answer 1

这个怎么样：

string filename = BitConverter.ToString(yourMD5ByteArray);

如果您更喜欢没有连字符的较​​短文件名，那么您可以使用：

string filename =
    BitConverter.ToString(yourMD5ByteArray).Replace("-", string.Empty);

Answer 2

System.Convert.ToBase64String

As a commenter pointed out -- normal base 64 encoding can contain a '/' character, which obivously will be a problem with filenames. However, there are other characters that are usable, such as an underscore - just replace all the '/' with an underscore.

string filename = Convert.ToBase64String(md5HashBytes).Replace("/","_");

Answer 3

Try this:

Guid guid = new Guid(md5HashBytes);
string hashString = guid.ToString("N"); 
// format: xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx

string hashString = guid.ToString("D"); 
// format: xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx

string hashString = guid.ToString("B"); 
// format: {xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx}

string hashString = guid.ToString("P"); 
// format: (xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)

Answer 4

尝试这个：

string Hash = Convert.ToBase64String(MD5.Create().ComputeHash(Encoding.UTF8.GetBytes("sample")));
//input "sample" returns = Xo/5v1W6NQgZnSLphBKb5g==

或者

string Hash = BitConverter.ToString(MD5.Create().ComputeHash(Encoding.UTF8.GetBytes("sample")));
//input "sample" returns = 5E-8F-F9-BF-55-BA-35-08-19-9D-22-E9-84-12-9B-E6

Answer 5

这可能是最安全的文件名。你总是得到一个十六进制字符串，而不必担心 / 或 + 等。

        byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(inputString));
        StringBuilder sBuilder = new StringBuilder();
        for (int i = 0; i < data.Length; i++)
        {
            sBuilder.Append(data[i].ToString("x2"));
        }
        string hashed = sBuilder.ToString();

Answer 6

如果这是 Windows，从技术上讲，使用 Base64 是不好的，文件名不区分大小写（至少在资源管理器视图中）.. 但在 base64 中，“a”与“A”不同，这意味着这可能不太可能，但你最终会得到更高的速率碰撞..

更好的选择是像 bitconverter 类这样的十六进制，或者如果您可以使用 base32 编码（在从 base64 和 base32 中删除填充后，在 128 位的情况下，将为您提供相似长度的文件名）。

Answer 7

尝试 MD5 的 Base32 哈希。它提供文件名安全的不区分大小写的字符串。

    string Base32Hash(string input)
    {
        byte[] buf = MD5.Create().ComputeHash(Encoding.UTF8.GetBytes(input));
        return String.Join("", buf.Select(b => "abcdefghijklmonpqrstuvwxyz234567"[b & 0x1F]));
    }