Michael Gordeev
83 lines
2.7 KiB
C#
83 lines
2.7 KiB
C#
using System;
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using System.Collections.Generic;
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using System.Security.Cryptography;
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using System.Text;
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namespace MyWebsite.Helpers
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{
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/// <summary>
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/// SHA512 Encryption algorithm
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/// </summary>
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public static class Encryptor
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{
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/// <summary>
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/// Computes string hash string using SHA512 encryption
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/// </summary>
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/// <param name="plainText">String which hash is to be computed</param>
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/// <param name="saltBytes">Salt bytes array (for hash verification)</param>
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/// <returns>Encrypted hash string</returns>
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public static string ComputeHash(string plainText, byte[] saltBytes = null)
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{
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// Generate salt in it's not provided.
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if (saltBytes == null)
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{
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saltBytes = new byte[new Random().Next(4, 8)];
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// Initialize a random number generator.
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using RNGCryptoServiceProvider rng = new RNGCryptoServiceProvider();
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// Fill the salt with cryptographically strong byte values.
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rng.GetNonZeroBytes(saltBytes);
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}
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// Initializing array, which will hold plain text and salt.
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List<byte> plainBytes = new List<byte>();
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plainBytes.AddRange(Encoding.UTF8.GetBytes(plainText));
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plainBytes.AddRange(saltBytes);
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// Initialize hashing algorithm class.
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using HashAlgorithm encryptor = new SHA512Managed();
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// Create array which will hold hash and original salt bytes.
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List<byte> hash = new List<byte>();
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// Compute hash value of our plain text with appended salt.
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hash.AddRange(encryptor.ComputeHash(plainBytes.ToArray()));
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hash.AddRange(saltBytes);
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// Convert result into a base64-encoded string.
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return Convert.ToBase64String(hash.ToArray());
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}
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/// <summary>
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/// Verifies that <paramref name="hash"/> belongs to <paramref name="plainText"/> string
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/// </summary>
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/// <param name="plainText">Oringinal text string</param>
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/// <param name="hash">SHA512 encrypted hash string</param>
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/// <returns><see cref="true"/> if hash belong to <paramref name="plainText"/> otherwise returns <see cref="false"/></returns>
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public static bool VerifyHash(string plainText, string hash)
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{
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// Convert base64-encoded hash value into a byte array.
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byte[] hashBytes = Convert.FromBase64String(hash);
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// Make sure that the specified hash value is long enough.
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if (hashBytes.Length < 64)
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return false;
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// Allocate array to hold original salt bytes retrieved from hash.
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byte[] saltBytes = new byte[hashBytes.Length - 64];
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// Copy salt from the end of the hash to the new array.
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for (int i = 0; i < saltBytes.Length; i++)
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saltBytes[i] = hashBytes[64 + i];
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// Compute a new hash string.
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string expectedHashString = ComputeHash(plainText, saltBytes);
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// If the computed hash matches the specified hash,
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// the plain text value must be correct.
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return hash == expectedHashString;
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}
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}
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} |