如何使用明文字符串和已知盐生成 md5 哈希

Question

我一直在疯狂地想弄明白这个问题。 C# 中是否有一种简单的方法来获取 "password123" 和盐 "vfs5%S]m(_*Y+Tk" 之类的字符串并生成单个 MD5 哈希。网站 http://free-online-web-tools.com/tool/md5 的基本功能，但使用 C#。

Answer 1

下面给出的函数为给定的纯文本值生成一个散列，returns 一个 base64 编码的结果。在计算哈希之前，会生成一个随机盐并将其附加到纯文本。这个salt存放在hash值的末尾，所以后面可以用来做hash验证。

要散列的明文值。该函数不检查此参数是否为空。

哈希算法的名称。允许的值为："MD5"、"SHA1"、"SHA256"、"SHA384" 和 "SHA512"（如果指定了任何其他值，将使用 MD5 哈希算法）。此值不区分大小写。

在您的情况下，将 hashAlgorithm 设置为 "MD5"

盐字节。此参数可以为空，在这种情况下将生成随机盐值。

哈希值格式为 base64 编码的字符串。

public static string ComputeHash(string   plainText,
                                 string   hashAlgorithm,
                                 byte[]   saltBytes)
{
    // If salt is not specified, generate it on the fly.
    if (saltBytes == null)
    {
        // Define min and max salt sizes.
        int minSaltSize = 4;
        int maxSaltSize = 8;

        // Generate a random number for the size of the salt.
        Random  random = new Random();
        int saltSize = random.Next(minSaltSize, maxSaltSize);

        // Allocate a byte array, which will hold the salt.
        saltBytes = new byte[saltSize];

        // Initialize a random number generator.
        RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();

        // Fill the salt with cryptographically strong byte values.
        rng.GetNonZeroBytes(saltBytes); 
    }

    // Convert plain text into a byte array.
    byte[] plainTextBytes = Encoding.UTF8.GetBytes(plainText);

    // Allocate array, which will hold plain text and salt.
    byte[] plainTextWithSaltBytes = 
            new byte[plainTextBytes.Length + saltBytes.Length];

    // Copy plain text bytes into resulting array.
    for (int i=0; i < plainTextBytes.Length; i++)
        plainTextWithSaltBytes[i] = plainTextBytes[i];

    // Append salt bytes to the resulting array.
    for (int i=0; i < saltBytes.Length; i++)
        plainTextWithSaltBytes[plainTextBytes.Length + i] = saltBytes[i];

    // Because we support multiple hashing algorithms, we must define
    // hash object as a common (abstract) base class. We will specify the
    // actual hashing algorithm class later during object creation.
    HashAlgorithm hash;

    // Make sure hashing algorithm name is specified.
    if (hashAlgorithm == null)
        hashAlgorithm = "";

    // Initialize appropriate hashing algorithm class.
    switch (hashAlgorithm.ToUpper())
    {
        case "SHA1":
            hash = new SHA1Managed();
            break;

        case "SHA256":
            hash = new SHA256Managed();
            break;

        case "SHA384":
            hash = new SHA384Managed();
            break;

        case "SHA512":
            hash = new SHA512Managed();
            break;

        default:
            hash = new MD5CryptoServiceProvider();
            break;
    }

    // Compute hash value of our plain text with appended salt.
    byte[] hashBytes = hash.ComputeHash(plainTextWithSaltBytes);

    // Create array which will hold hash and original salt bytes.
    byte[] hashWithSaltBytes = new byte[hashBytes.Length + 
                                        saltBytes.Length];

    // Copy hash bytes into resulting array.
    for (int i=0; i < hashBytes.Length; i++)
        hashWithSaltBytes[i] = hashBytes[i];

    // Append salt bytes to the result.
    for (int i=0; i < saltBytes.Length; i++)
        hashWithSaltBytes[hashBytes.Length + i] = saltBytes[i];

    // Convert result into a base64-encoded string.
    string hashValue = Convert.ToBase64String(hashWithSaltBytes);

    // Return the result.
    return hashValue;
}

更多详情refer here.

如何使用明文字符串和已知盐生成 md5 哈希

How to generate an md5 hash with a plaintext string and a known salt

c#

passwords

md5

salt