我使用以下C＃代码从字符串计算MD5哈希。它运行良好，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生成一个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是好的，但我认为客户输入代码是无聊的！
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();
}
}
.NET Core 2.1及更高版本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);
}
}
如果你确定你的字符串足够小并且替换encoding.GetBytes by unsafe int GetBytes（ReadOnlySpan chars，Span bytes）替代，你可以进一步优化它。
StringBuilder sb= new StringBuilder();
for (int i = 0; i < tmpHash.Length; i++)
{
sb.Append(tmpHash[i].ToString("x2"));
}
这个解决方案需要c＃7.2并利用Span<T>。无论输入大小如何，这都会分配固定数量的内存，并且比接受的答案更快。注意，如果需要，您仍然需要调用.Replace("-", string.Empty).ToLowerInvariant()来格式化结果。
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 = stackalloc 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());
}
}
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);
}
// 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
完全取决于您想要实现的目标。从技术上讲，您可以从MD5哈希的结果中获取前12个字符，但MD5的规范是生成32个字符。
减小散列的大小会降低安全性，并增加冲突和系统崩溃的可能性。
也许如果你让我们更多地了解你想要实现的目标，我们可能会提供更多帮助。
您可以使用Convert.ToBase64String将MD5的16字节输出转换为~24字符串。在不降低安全性的情况下更好一点。 （以j9JIbSY8HuT89/pwdC8jlw==为例）
尝试使用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")
);
}
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);
}
}
MD5哈希是128位，因此您不能用十六进制表示少于32个字符...
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();
}
}
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();