C# 从字符串计算 MD5 哈希
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Calculate a MD5 hash from a string
提问by Muhamad Jafarnejad
I use the following C# code to calculate a MD5 hash from a string.
It works well and generates a 32-character hex string like this:
900150983cd24fb0d6963f7d28e17f72
我使用以下 C# 代码从字符串计算 MD5 哈希值。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...
Is there a way to use code like this to generate a 16-character hex string (or 12-character string)? A 32-character hex string is good but I think it'll be boring for the customer to enter the code!
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！
回答by KingCronus
Depends entirely on what you are trying to achieve. Technically, you could just take the first 12 characters from the result of the MD5 hash, but the specification of MD5 is to generate a 32 char one.
完全取决于您要实现的目标。从技术上讲，您可以只从 MD5 散列的结果中取出前 12 个字符，但 MD5 的规范是生成一个 32 个字符的字符。
Reducing the size of the hash reduces the security, and increases the chance of collisions and the system being broken.
减少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。
Perhaps if you let us know more about what you are trying to achieve we may be able to assist more.
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。
回答by Thomas Levesque
A MD5 hash is 128 bits, so you can't represent it in hex with less than 32 characters...
MD5 散列是 128 位，所以你不能用少于 32 个字符的十六进制表示它......
回答by L.B
You can use Convert.ToBase64Stringto convert 16 byte output of MD5 to a ~24 char string. A little bit better without reducing security. (j9JIbSY8HuT89/pwdC8jlw==for your example)
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更好一点。（j9JIbSY8HuT89/pwdC8jlw==以您为例）
回答by Michael
// 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
回答by Suhrob Samiev
StringBuilder sb= new StringBuilder();
for (int i = 0; i < tmpHash.Length; i++)
{
sb.Append(tmpHash[i].ToString("x2"));
}
回答by Anant Dabhi
As per MSDN
根据MSDN
Create MD5 :
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();
}
}
回答by craigdfrench
Was trying to create a string representation of MD5 hash using LINQ, however, none of the answers were LINQ solutions, therefore adding this to the smorgasbord of available solutions.
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")
);
}
回答by Tomas Kubes
I suppose it is better to use UTF-8 encoding in the string MD5.
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();
}
}
回答by Kristian Jay
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();
回答by Think Big
Support string and file stream.
支持字符串和文件流。
examples
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);
}
}
