c# - 从字符串计算 MD5 哈希

Question

我使用以下 C# 代码从字符串计算 MD5 哈希。它运行良好并生成一个 32 个字符的十六进制字符串，如下所示： 900150983cd24fb0d6963f7d28e17f72

string sSourceData;
byte[] tmpSource;
byte[] tmpHash;
sSourceData = "MySourceData";

//Create a byte array from source data.
tmpSource = ASCIIEncoding.ASCII.GetBytes(sSourceData);
tmpHash = new MD5CryptoServiceProvider().ComputeHash(tmpSource);

// and then convert tmpHash to string...

有没有办法使用这样的代码来生成 16 个字符的十六进制字符串（或 12 个字符的字符串）？一个 32 个字符的十六进制字符串很好，但我认为客户输入代码会很无聊！

score 283 · Accepted Answer

根据MSDN

创建MD5：

public static string CreateMD5(string input)
{
    // Use input string to calculate MD5 hash
    using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
    {
        byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
        byte[] hashBytes = md5.ComputeHash(inputBytes);

        // Convert the byte array to hexadecimal string
        StringBuilder sb = new StringBuilder();
        for (int i = 0; i < hashBytes.Length; i++)
        {
            sb.Append(hashBytes[i].ToString("X2"));
        }
        return sb.ToString();
    }
}

score 103 · Accepted Answer

// given, a password in a string
string password = @"1234abcd";

// byte array representation of that string
byte[] encodedPassword = new UTF8Encoding().GetBytes(password);

// need MD5 to calculate the hash
byte[] hash = ((HashAlgorithm) CryptoConfig.CreateFromName("MD5")).ComputeHash(encodedPassword);

// string representation (similar to UNIX format)
string encoded = BitConverter.ToString(hash)
   // without dashes
   .Replace("-", string.Empty)
   // make lowercase
   .ToLower();

// encoded contains the hash you want

score 18 · Accepted Answer

试图使用 LINQ 创建 MD5 哈希的字符串表示，但是，没有一个答案是 LINQ 解决方案，因此将其添加到可用解决方案的大杂烩中。

string result;
using (MD5 hash = MD5.Create())
{
    result = String.Join
    (
        "",
        from ba in hash.ComputeHash
        (
            Encoding.UTF8.GetBytes(observedText)
        ) 
        select ba.ToString("x2")
    );
}

score 12 · Accepted Answer

您可以使用Convert.ToBase64String将 MD5 的 16 字节输出转换为 ~24 字符字符串。在不降低安全性的情况下好一点。（j9JIbSY8HuT89/pwdC8jlw==对于你的例子）

score 10 · Accepted Answer

完全取决于您要达到的目标。从技术上讲，您可以只从 MD5 散列的结果中获取前 12 个字符，但 MD5 的规范是生成一个 32 个字符的字符。

减小散列的大小会降低安全性，并增加冲突和系统被破坏的机会。

也许如果您让我们更多地了解您正在努力实现的目标，我们可能会提供更多帮助。

score 8 · Accepted Answer

我想最好在字符串 MD5 中使用 UTF-8 编码。

public static string MD5(this string s)
{
    using var provider = System.Security.Cryptography.MD5.Create();        
    StringBuilder builder = new StringBuilder();                           

    foreach (byte b in provider.ComputeHash(Encoding.UTF8.GetBytes(s)))
        builder.Append(b.ToString("x2").ToLower());

    return builder.ToString();        
}

score 7 · Accepted Answer

支持字符串和文件流。

例子

string hashString = EasyMD5.Hash("My String");

string hashFile = EasyMD5.Hash(System.IO.File.OpenRead("myFile.txt"));

-

   class EasyMD5
        {
            private static string GetMd5Hash(byte[] data)
            {
                StringBuilder sBuilder = new StringBuilder();
                for (int i = 0; i < data.Length; i++)
                    sBuilder.Append(data[i].ToString("x2"));
                return sBuilder.ToString();
            }

            private static bool VerifyMd5Hash(byte[] data, string hash)
            {
                return 0 == StringComparer.OrdinalIgnoreCase.Compare(GetMd5Hash(data), hash);
            }

            public static string Hash(string data)
            {
                using (var md5 = MD5.Create())
                    return GetMd5Hash(md5.ComputeHash(Encoding.UTF8.GetBytes(data)));
            }
            public static string Hash(FileStream data)
            {
                using (var md5 = MD5.Create())
                    return GetMd5Hash(md5.ComputeHash(data));
            }

            public static bool Verify(string data, string hash)
            {
                using (var md5 = MD5.Create())
                    return VerifyMd5Hash(md5.ComputeHash(Encoding.UTF8.GetBytes(data)), hash);
            }

            public static bool Verify(FileStream data, string hash)
            {
                using (var md5 = MD5.Create())
                    return VerifyMd5Hash(md5.ComputeHash(data), hash);
            }
        }

score 6 · Accepted Answer

public static string Md5(string input, bool isLowercase = false)
{
    using (var md5 = MD5.Create())
    {
        var byteHash = md5.ComputeHash(Encoding.UTF8.GetBytes(input));
        var hash = BitConverter.ToString(byteHash).Replace("-", "");
        return (isLowercase) ? hash.ToLower() : hash;
    }
}

score 5 · Accepted Answer

此解决方案需要 c# 8 并利用Span<T>. 请注意，如果需要，您仍然需要调用.Replace("-", string.Empty).ToLowerInvariant()以格式化结果。

public static string CreateMD5(ReadOnlySpan<char> input)
{
    var encoding = System.Text.Encoding.UTF8;
    var inputByteCount = encoding.GetByteCount(input);
    using var md5 = System.Security.Cryptography.MD5.Create();

    Span<byte> bytes = inputByteCount < 1024
        ? stackalloc byte[inputByteCount]
        : new byte[inputByteCount];
    Span<byte> destination = stackalloc byte[md5.HashSize / 8];

    encoding.GetBytes(input, bytes);

    // checking the result is not required because this only returns false if "(destination.Length < HashSizeValue/8)", which is never true in this case
    md5.TryComputeHash(bytes, destination, out int _bytesWritten);

    return BitConverter.ToString(destination.ToArray());
}

score 5 · Accepted Answer

这是我的实用程序函数，如果需要UTF8，可以替换为ASCII：

    public static byte[] MD5Hash(string message)
    {
        return MD5.Create().ComputeHash(Encoding.UTF8.GetBytes(message));
    }

score 4 · Accepted Answer

4

MD5 哈希是 128 位，所以你不能用少于 32 个字符的十六进制表示它......

于 2012-07-12T14:28:52.647 回答

score 4 · Accepted Answer

System.Text.StringBuilder hash = new System.Text.StringBuilder();
        System.Security.Cryptography.MD5CryptoServiceProvider md5provider = new System.Security.Cryptography.MD5CryptoServiceProvider();
        byte[] bytes = md5provider.ComputeHash(new System.Text.UTF8Encoding().GetBytes(YourEntryString));

        for (int i = 0; i < bytes.Length; i++)
        {
            hash.Append(bytes[i].ToString("x2")); //lowerCase; X2 if uppercase desired
        }
        return hash.ToString();

score 4 · Accepted Answer

.NET Core 2.1 及更高版本的现有答案的更快替代方案：

public static string CreateMD5(string s)
{
    using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
    {
        var encoding = Encoding.ASCII;
        var data = encoding.GetBytes(s);

        Span<byte> hashBytes = stackalloc byte[16];
        md5.TryComputeHash(data, hashBytes, out int written);
        if(written != hashBytes.Length)
            throw new OverflowException();


        Span<char> stringBuffer = stackalloc char[32];
        for (int i = 0; i < hashBytes.Length; i++)
        {
            hashBytes[i].TryFormat(stringBuffer.Slice(2 * i), out _, "x2");
        }
        return new string(stringBuffer);
    }
}

如果您确定您的字符串足够小并用 unsafe int GetBytes(ReadOnlySpan chars, Span bytes) 替代 encoding.GetBytes 替换，您可以进一步优化它。

score 4 · Accepted Answer

Idk 任何关于 16 个字符的十六进制字符串....

using System;
using System.Security.Cryptography;
using System.Text;

但这是我在一行中创建 MD5 哈希的方法。

string hash = BitConverter.ToString(MD5.Create().ComputeHash(Encoding.ASCII.GetBytes("THIS STRING TO MD5"))).Replace("-","");

score 3 · Accepted Answer

扩展Anant Dabhi的答案

辅助方法：

using System.Text;

namespace XYZ.Helpers
{
    public static class EncryptionHelper
    {
        public static string ToMD5(this string input)
        {
            // Use input string to calculate MD5 hash
            using (System.Security.Cryptography.MD5 md5 = System.Security.Cryptography.MD5.Create())
            {
                byte[] inputBytes = System.Text.Encoding.ASCII.GetBytes(input);
                byte[] hashBytes = md5.ComputeHash(inputBytes);

                // Convert the byte array to hexadecimal string
                StringBuilder sb = new StringBuilder();
                for (int i = 0; i < hashBytes.Length; i++)
                {
                    sb.Append(hashBytes[i].ToString("X2"));
                }
                return sb.ToString();
            }
        }
    }
}

score 2 · Accepted Answer

https://docs.microsoft.com/en-us/dotnet/api/system.security.cryptography.md5?view=netframework-4.7.2

using System;
using System.Security.Cryptography;
using System.Text;

    static string GetMd5Hash(string input)
            {
                using (MD5 md5Hash = MD5.Create())
                {

                    // Convert the input string to a byte array and compute the hash.
                    byte[] data = md5Hash.ComputeHash(Encoding.UTF8.GetBytes(input));

                    // Create a new Stringbuilder to collect the bytes
                    // and create a string.
                    StringBuilder sBuilder = new StringBuilder();

                    // Loop through each byte of the hashed data 
                    // and format each one as a hexadecimal string.
                    for (int i = 0; i < data.Length; i++)
                    {
                        sBuilder.Append(data[i].ToString("x2"));
                    }

                    // Return the hexadecimal string.
                    return sBuilder.ToString();
                }
            }

            // Verify a hash against a string.
            static bool VerifyMd5Hash(string input, string hash)
            {
                // Hash the input.
                string hashOfInput = GetMd5Hash(input);

                // Create a StringComparer an compare the hashes.
                StringComparer comparer = StringComparer.OrdinalIgnoreCase;

                return 0 == comparer.Compare(hashOfInput, hash);

            }

score 2 · Accepted Answer

我想提供一个替代方案，它在我的测试（.NET 4.7.2）中的执行速度至少比craigdfrench 的答案快 10%：

public static string GetMD5Hash(string text)
{
    using ( var md5 = MD5.Create() )
    {
        byte[] computedHash = md5.ComputeHash( Encoding.UTF8.GetBytes(text) );
        return new System.Runtime.Remoting.Metadata.W3cXsd2001.SoapHexBinary(computedHash).ToString();
    }
}

如果您更喜欢using System.Runtime.Remoting.Metadata.W3cXsd2001;放在顶部，可以使方法主体更易于阅读：

using ( var md5 = MD5.Create() )
{
    return new SoapHexBinary( md5.ComputeHash( Encoding.UTF8.GetBytes(text) ) ).ToString();
}

很明显，但为了完整起见，在 OP 的上下文中，它将用作：

sSourceData = "MySourceData";
tmpHash = GetMD5Hash(sSourceData);

score 1 · Accepted Answer

StringBuilder sb= new StringBuilder();
for (int i = 0; i < tmpHash.Length; i++)
{
   sb.Append(tmpHash[i].ToString("x2"));
}

score 1 · Accepted Answer

    public static string GetMD5(string encryptString)
    {
        var passByteCrypt = new MD5CryptoServiceProvider().ComputeHash(Encoding.UTF8.GetBytes(encryptString));

        return ByteArrayToString(passByteCrypt);
    }
    public static string ByteArrayToString(byte[] bytes)
    {
        var output = new StringBuilder(bytes.Length);

        foreach (var t in bytes)
        {
            output.Append(t.ToString("X2"));
        }

        return output.ToString().ToLower();
    }

这是简单的 md5 ByteCrypt

score 1 · Accepted Answer

这是一个精简版。

private string CreateMD5(string myText)
{
    var hash = System.Security.Cryptography.MD5.Create()
        .ComputeHash(System.Text.Encoding.ASCII.GetBytes(myText ?? ""));
    return string.Join("", Enumerable.Range(0, hash.Length).Select(i => hash[i].ToString("x2")));
}

c# - 从字符串计算 MD5 哈希

20 回答 20

Related

Reference