其中是.net中Sha256的更新函数

本文关键字：更新 函数 net Sha256 | 更新日期: 2023-09-27 17:58:56

我在c++代码中使用了Sha256类的更新函数，将几个字符串包含在一个哈希值中，但在.net类Sha256中找不到这个函数。这个函数在C++实现、Sha的Java实现中都有，但在.net中没有？

C++中的示例代码：

l_ceSHA2.Init();
for ( l_dwordCnt = 0; l_dwordCnt < l_dwordHashRounds; l_dwordCnt++)
{
    l_ceSHA2.Update( mp_strPassword, strlen( mp_strPassword )));
    l_ceSHA2.Update( mp_byteSalt, 32 );
}
l_ceSHA2.Final( mp_byteCryptoKey);

所以，这就像PBKDF，但更容易。

C中的Sha256代码用于参考

其中是.net中Sha256的更新函数

您可以使用TransformBlock。下面是一个示例，展示了如何：

using System;
using System.Text;
using System.Security.Cryptography;
// Example code for using TransformBlock to hash data in chunks
namespace HashTest
{
    class HashTest
    {
        static void Main(string[] args)
        {
            SHA256 hash = SHA256.Create();
            ASCIIEncoding encoding = new ASCIIEncoding();
            string password = "password";
            // Hash a string using ComputeHash
            string sourcetext = password;
            Console.WriteLine(sourcetext);
            byte[] sourcebytes = encoding.GetBytes(sourcetext);
            byte[] hashBytes = hash.ComputeHash(sourcebytes);
            string hashStr = BitConverter.ToString(hashBytes).Replace("-", "");
            Console.WriteLine(hashStr);
            // Hash exactly two copies of a string
            // (used to cross verify other methods below).
            Console.WriteLine();
            sourcetext = password + password;
            Console.WriteLine(sourcetext);
            sourcebytes = encoding.GetBytes(sourcetext);
            hashBytes = hash.ComputeHash(sourcebytes);
            hashStr = BitConverter.ToString(hashBytes).Replace("-", "");
            Console.WriteLine(hashStr);
            // Hash a string using TransformFinalBlock
            Console.WriteLine();
            sourcetext = password;
            sourcebytes = encoding.GetBytes(sourcetext);
            Console.WriteLine(sourcetext);
            hash.TransformFinalBlock(sourcebytes, 0, sourcebytes.Length);
            hashBytes = hash.Hash;
            hashStr = BitConverter.ToString(hashBytes).Replace("-", "");
            Console.WriteLine(hashStr);
            // At this point we've finalized the hash. To
            // reuse it we must first call Initialize().
            // Hash string twice using TransformBlock / TransformFinalBlock
            Console.WriteLine();
            hash.Initialize();
            sourcetext = password;
            sourcebytes = encoding.GetBytes(sourcetext);
            Console.Write(sourcetext);
            hash.TransformBlock(sourcebytes, 0, sourcebytes.Length, null, 0);
            Console.WriteLine(sourcetext);
            hash.TransformFinalBlock(sourcebytes, 0, sourcebytes.Length);
            hashBytes = hash.Hash;
            hashStr = BitConverter.ToString(hashBytes).Replace("-", "");
            Console.WriteLine(hashStr);
            // Hash string twice using TransformBlock in a loop
            Console.WriteLine();
            hash.Initialize();
            sourcetext = password;
            sourcebytes = encoding.GetBytes(sourcetext);
            for (int i = 0; i < 2; ++i)
            {
                Console.Write(sourcetext);
                hash.TransformBlock(sourcebytes, 0, sourcebytes.Length, null, 0);
            }
            Console.WriteLine();
            hash.TransformFinalBlock(sourcebytes, 0, 0);
            hashBytes = hash.Hash;
            hashStr = BitConverter.ToString(hashBytes).Replace("-", "");
            Console.WriteLine(hashStr);
        }
    }
}
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