ASP.NET Membership使用的默认哈希算法是什么?我如何更改它?
ASP.NET Membership使用的默认哈希算法是什么?我如何更改它?
鉴于谷歌搜索“membership provider哈希算法”将此答案列为第一个结果,并且将被推断的基督教福音,我有责任警告人们不要像这样使用Membership Provider和使用SHA-1、MD5等哈希值来对数据库中的密码进行混淆。
使用派生密钥函数,如bcrypt、scrypt或(如果需要符合FIPS标准)PBKDF2,其中工作因子足以使单个密码的哈希时间尽可能接近1000ms或更长时间。
现在,哈希很容易被强力破解,最近历史上还有大量数据泄漏的例子。为了防止用户的密码在下一次黑客攻击中出现在pastebin上,请确保密码使用需要充分长时间计算的函数进行哈希!
请尝试使用IdentityReboot或至少Troy Hunt讨论的Microsoft的新实现,而不是Membership Provider。
有趣的是,在上述谷歌搜索结果中,我发现一篇教程向人们展示了使用流行工具如JtR或Hashcat轻松破解这些密码哈希的方法。在自定义GPU设备上,SHA1可以以惊人的速度每秒48867万个哈希值被破解!使用免费字典如rockyou或类似字典,一个有动力的人很快就能获得大多数用户的密码。作为开发者,保护用户密码安全是你的道德责任。
默认的哈希算法是SHA1,但他们也会对其进行盐值处理和base64编码:
public string EncodePassword(string pass, string salt)
{
byte[] bytes = Encoding.Unicode.GetBytes(pass);
byte[] src = Encoding.Unicode.GetBytes(salt);
byte[] dst = new byte[src.Length + bytes.Length];
Buffer.BlockCopy(src, 0, dst, 0, src.Length);
Buffer.BlockCopy(bytes, 0, dst, src.Length, bytes.Length);
HashAlgorithm algorithm = HashAlgorithm.Create("SHA1");
byte[] inArray = algorithm.ComputeHash(dst);
return Convert.ToBase64String(inArray);
}
private byte[] ConvertPasswordForStorage(string Password)
{
System.Text.UnicodeEncoding ue =
new System.Text.UnicodeEncoding();
byte[] uePassword = ue.GetBytes(Password);
byte[] RetVal = null;
switch (_PasswordFormat)
{
case MembershipPasswordFormat.Clear:
RetVal = uePassword;
break;
case MembershipPasswordFormat.Hashed:
HMACSHA1 SHA1KeyedHasher = new HMACSHA1();
SHA1KeyedHasher.Key = _ValidationKey;
RetVal = SHA1KeyedHasher.ComputeHash(uePassword);
break;
case MembershipPasswordFormat.Encrypted:
TripleDESCryptoServiceProvider tripleDes = new
TripleDESCryptoServiceProvider();
tripleDes.Key = _DecryptionKey;
tripleDes.IV = new byte[8];
MemoryStream mStreamEnc = new MemoryStream();
CryptoStream cryptoStream = new CryptoStream(mStreamEnc,
tripleDes.CreateEncryptor(),
CryptoStreamMode.Write);
cryptoStream.Write(uePassword, 0, uePassword.Length);
cryptoStream.FlushFinalBlock();
RetVal = mStreamEnc.ToArray();
cryptoStream.Close();
break;
}
return RetVal;
}
private string GetHumanReadablePassword(byte[] StoredPassword)
{
System.Text.UnicodeEncoding ue = new System.Text.UnicodeEncoding();
string RetVal = null;
switch (_PasswordFormat)
{
case MembershipPasswordFormat.Clear:
RetVal = ue.GetString(StoredPassword);
break;
case MembershipPasswordFormat.Hashed:
throw new ApplicationException(
"Password cannot be recovered from a hashed format");
case MembershipPasswordFormat.Encrypted:
TripleDESCryptoServiceProvider tripleDes =
new TripleDESCryptoServiceProvider();
tripleDes.Key = _DecryptionKey;
tripleDes.IV = new byte[8];
CryptoStream cryptoStream =
new CryptoStream(new MemoryStream(StoredPassword),
tripleDes.CreateDecryptor(), CryptoStreamMode.Read);
MemoryStream msPasswordDec = new MemoryStream();
int BytesRead = 0;
byte[] Buffer = new byte[32];
while ((BytesRead = cryptoStream.Read(Buffer, 0, 32)) > 0)
{
msPasswordDec.Write(Buffer, 0, BytesRead);
}
cryptoStream.Close();
RetVal = ue.GetString(msPasswordDec.ToArray());
msPasswordDec.Close();
break;
}
return RetVal;
}
Ryan Christensen的上面回答并不完整。它将盐转换为byte[]的部分不正确。
这是我在为客户实现解决方案时使用的可行示例:
public string Hash(string value, string salt)
{
byte[] bytes = Encoding.Unicode.GetBytes(value);
byte[] src = Convert.FromBase64String(salt);
byte[] dst = new byte[src.Length + bytes.Length];
Buffer.BlockCopy(src, 0, dst, 0, src.Length);
Buffer.BlockCopy(bytes, 0, dst, src.Length, bytes.Length);
HashAlgorithm algorithm = HashAlgorithm.Create("SHA1");
byte[] inArray = algorithm.ComputeHash(dst);
return Convert.ToBase64String(inArray);
}
var fixedSalt = Convert.ToBase64String(Encoding.Unicode.GetBytes(oldSalt);
- jpatteHashAlgorithm algorithm = HashAlgorithm.Create("SHA512");
。 PBKDF2或SCRYPT或ARGON2是最新一代的密码哈希算法。不幸的是,它们目前还不是.NET类库的一部分。 - jitin142) 如果您正在使用IIS 6,可以通过web.config文件中的membership元素更改哈希算法类型:
<membership
defaultProvider="provider name"
userIsOnlineTimeWindow="number of minutes"
hashAlgorithmType="SHA1">
<providers>...</providers>
</membership>
MD5
、RIPEMD160
、SHA1
、SHA256
、SHA384
、SHA512
。重要的部分在于所有这些类都继承自 HashAlgorithm
。
hashAlgorithmType 属性的值也可以是 machine.config 文件中 cryptoNameMapping 元素的条目。如果需要第三方哈希算法,则可以使用此选项。如果您正在使用 ASP.Net 2 或更高版本,则可以在 C:\WINDOWS\Microsoft.NET\Framework\v2.0.50727\CONFIG
中找到 machine.config 文件。您可以在 here 中阅读更多关于设置这些值的信息。在 .NET 4.0 Framework 中,默认的哈希算法已更改为HMACSHA256。
请注意,与 SHA-1 不同,HMAC SHA-256 是一种密钥哈希。如果您的哈希表现出非确定性行为,则可能没有设置密钥,强制使用随机密钥。类似以下内容可能会是罪魁祸首(这就是我刚刚花了一个小时找出来的 :p)。
HashAlgorithm.Create(Membership.HashAlgorithmType)
如果您希望它能够与现有的提供程序一起使用,您可以使用此指南将其恢复为以前的默认设置。
哈希算法中有一个更正,你必须使用:
byte[] src = Convert.FromBase64String(salt);
byte[] src = Encoding.Unicode.GetBytes(salt);
阅读文章 http://svakodnevnica.com.ba/index.php?option=com_kunena&func=view&catid=4&id=4&Itemid=5&lang=en#6
Zetetic 只需两行代码就可以完成! 哈希算法PBKDF2比使用SHA1或SHA256-SHA512等更好。像PBKDF2、SCRYPT或ARGON2这样的最新算法在哈希方面处于领先地位。但在这种情况下使用PBKDF2很有用,因为.NET中的Rfc2898DeriveBytes
类实现了它。使用这个库到目前为止非常棒,但是还有一些小问题,例如:
a. Zetetic默认使用5000次迭代。如果使用Pbkdf2Hash256K
,则可自定义。
b. Zetetic使用Rfc2898DeriveBytes
,而Rfc2898DeriveBytes
基于某种原因的HMACSHA1
,无法自定义。
好消息!我已经定制了Rfc2898DeriveBytes
,以使用128,000次迭代的HMACSHA512
,以便SQLMembershipProvider可以使用迄今为止不可用的PBKDF2。为了实现这一点,我将Zetetic的代码与我的Rfc2898DeriveBytes
实现组合起来,如下所示:
using System.Security.Cryptography;
namespace custom.hashing.keyderivation
{
/// <summary>
/// This derived class of PBKDF2Hash provided necessary capabilities to SQLMembershipProvider in order to hash passwords in PBKDF2 way with 128,000 iterations.
/// </summary>
public class PBKDF2Hash : KeyedHashAlgorithm
{
private const int kHashBytes = 64;
private System.IO.MemoryStream _ms;
public int WorkFactor { get; set; }
public PBKDF2Hash()
: base()
{
this.WorkFactor = 128000;
this.Key = new byte[32]; // 32 Bytes will give us 256 bits.
using (var rngCsp = new RNGCryptoServiceProvider())
{
// Fill the array with cryptographically secure random bytes.
rngCsp.GetBytes(this.Key);
}
}
/// <summary>
/// Hash size in bits
/// </summary>
public override int HashSize
{
get
{
return kHashBytes * 8;
}
}
protected override void HashCore(byte[] array, int ibStart, int cbSize)
{
(_ms = _ms ?? new System.IO.MemoryStream()).Write(array, ibStart, cbSize);
}
protected override byte[] HashFinal()
{
if (this.Key == null || this.Key.Length == 0)
{
throw new CryptographicException("Missing KeyedAlgorithm key");
}
_ms.Flush();
var arr = _ms.ToArray();
_ms = null;
using (var hmac = new HMACSHA512())
{
return new MyRfc2898DeriveBytes(arr, this.Key, this.WorkFactor, hmac).GetBytes(kHashBytes);
}
}
public override void Initialize()
{
_ms = null;
}
}
// ==++==
//
// Copyright (c) Microsoft Corporation. All rights reserved.
//
// ==--==
// <OWNER>Microsoft</OWNER>
//
//
// Rfc2898DeriveBytes.cs
//
// This implementation follows RFC 2898 recommendations. See http://www.ietf.org/rfc/Rfc2898.txt
/// <summary>
/// Microsoft has implemented PBKDF2 but with HMACSHA1. We are customizing this class to use HMACSHA512 in hashing process.
/// </summary>
public class MyRfc2898DeriveBytes : DeriveBytes
{
private byte[] m_buffer;
private byte[] m_salt;
private HMAC m_hmac; // The pseudo-random generator function used in PBKDF2
private uint m_iterations;
private uint m_block;
private int m_startIndex;
private int m_endIndex;
private int m_blockSize;
//
// public constructors
//
// This method needs to be safe critical, because in debug builds the C# compiler will include null
// initialization of the _safeProvHandle field in the method. Since SafeProvHandle is critical, a
// transparent reference triggers an error using PasswordDeriveBytes.
[SecuritySafeCritical]
public MyRfc2898DeriveBytes(byte[] password, byte[] salt, int iterations, HMAC hmac)
{
Salt = salt;
IterationCount = iterations;
hmac.Key = password;
m_hmac = hmac;
// m_blockSize is in bytes, HashSize is in bits.
m_blockSize = hmac.HashSize >> 3;
Initialize();
}
//
// public properties
//
public int IterationCount
{
get { return (int)m_iterations; }
set
{
if (value <= 0)
throw new ArgumentOutOfRangeException("value", "Error: Iteration count is zero or less");
m_iterations = (uint)value;
Initialize();
}
}
public byte[] Salt
{
get { return (byte[])m_salt.Clone(); }
set
{
if (value == null)
throw new ArgumentNullException("value");
if (value.Length < 8)
throw new ArgumentException("Error: Salt size is less than 8");
m_salt = (byte[])value.Clone();
Initialize();
}
}
//
// public methods
//
public override byte[] GetBytes(int cb)
{
if (cb <= 0)
{ throw new ArgumentOutOfRangeException("cb", "Error: Hash size is zero or less"); }
Contract.Assert(m_blockSize > 0);
byte[] password = new byte[cb];
int offset = 0;
int size = m_endIndex - m_startIndex;
if (size > 0)
{
if (cb >= size)
{
Buffer.BlockCopy(m_buffer, m_startIndex, password, 0, size);
m_startIndex = m_endIndex = 0;
offset += size;
}
else
{
Buffer.BlockCopy(m_buffer, m_startIndex, password, 0, cb);
m_startIndex += cb;
return password;
}
}
Contract.Assert(m_startIndex == 0 && m_endIndex == 0, "Invalid start or end index in the internal buffer.");
while (offset < cb)
{
byte[] T_block = Func();
int remainder = cb - offset;
if (remainder > m_blockSize)
{
Buffer.BlockCopy(T_block, 0, password, offset, m_blockSize);
offset += m_blockSize;
}
else
{
Buffer.BlockCopy(T_block, 0, password, offset, remainder);
offset += remainder;
Buffer.BlockCopy(T_block, remainder, m_buffer, m_startIndex, m_blockSize - remainder);
m_endIndex += (m_blockSize - remainder);
return password;
}
}
return password;
}
public override void Reset()
{
Initialize();
}
protected override void Dispose(bool disposing)
{
base.Dispose(disposing);
if (disposing)
{
if (m_hmac != null)
{
((IDisposable)m_hmac).Dispose();
}
if (m_buffer != null)
{
Array.Clear(m_buffer, 0, m_buffer.Length);
}
if (m_salt != null)
{
Array.Clear(m_salt, 0, m_salt.Length);
}
}
}
private void Initialize()
{
if (m_buffer != null)
Array.Clear(m_buffer, 0, m_buffer.Length);
m_buffer = new byte[m_blockSize];
m_block = 1;
m_startIndex = m_endIndex = 0;
}
internal static byte[] GetBytesFromInt(uint i)
{
return unchecked(new byte[] { (byte)(i >> 24), (byte)(i >> 16), (byte)(i >> 8), (byte)i });
}
// This function is defined as follow :
// Func (S, i) = HMAC(S || i) | HMAC2(S || i) | ... | HMAC(iterations) (S || i)
// where i is the block number.
private byte[] Func()
{
byte[] INT_block = GetBytesFromInt(m_block);
m_hmac.TransformBlock(m_salt, 0, m_salt.Length, null, 0);
m_hmac.TransformBlock(INT_block, 0, INT_block.Length, null, 0);
m_hmac.TransformFinalBlock(new byte[0], 0, 0);
byte[] temp = m_hmac.Hash;
m_hmac.Initialize();
byte[] ret = temp;
for (int i = 2; i <= m_iterations; i++)
{
m_hmac.TransformBlock(temp, 0, temp.Length, null, 0);
m_hmac.TransformFinalBlock(new byte[0], 0, 0);
temp = m_hmac.Hash;
for (int j = 0; j < m_blockSize; j++)
{
ret[j] ^= temp[j];
}
m_hmac.Initialize();
}
// increment the block count.
if (m_block == uint.MaxValue)
{ throw new InvalidOperationException("Derived key too long."); }
m_block++;
return ret;
}
}
将以下行添加到Global.asax的Application_Start事件或项目的相应启动文件中:
System.Security.Cryptography.CryptoConfig.AddAlgorithm(typeof(custom.hashing.keyderivation.PBKDF2Hash), "PBKDF2Hash_HB");
并将web.config更改为:
<membership defaultProvider="sitecore" hashAlgorithmType="PBKDF2Hash_HB">
构建此答案的参考资料来自于:
我附上一个代码片段,展示了与Rawbert在上面给出的F#中的答案相同的代码
open System
open System.Security.Cryptography
open System.Text
module PasswordHelper =
let EncodePassword(pass : string, salt : string) =
let bytes = Encoding.Unicode.GetBytes(pass)
let src = Convert.FromBase64String(salt)
let dst : byte array = Array.zeroCreate (src.Length + bytes.Length)
Buffer.BlockCopy(src, 0, dst, 0, src.Length)
Buffer.BlockCopy(bytes, 0, dst, src.Length, bytes.Length)
let algorithm = HashAlgorithm.Create("SHA1")
let inArray = algorithm.ComputeHash(dst)
Convert.ToBase64String(inArray)
这是来自一个活跃应用的可运行代码