C# PasswordDeriveBytes 混淆 [英] C# PasswordDeriveBytes Confusion

问题描述

我在 C# 中有以下代码

I have following code in C#

PasswordDeriveBytes DerivedPassword = new PasswordDeriveBytes(Password, SaltValueBytes, HashAlgorithm, PasswordIterations);
byte[] KeyBytes = DerivedPassword.GetBytes(32);

我正在使用SHA1"哈希算法.

I am using "SHA1" hashing algorithm.

根据 SHA1 定义，它生成 160 位(20 字节)的密钥.我的问题是 GetBytes 方法如何从 DerivedPassword 中获取 32 个字节，GetBytes 方法背后使用了什么算法?

According to SHA1 definition, its generate 160 bits (20 bytes) key. My question is how GetBytes method get 32 bytes from DerivedPassword, what algorithm used behind GetBytes method?

推荐答案

Microsoft 对原始 PKCS#5(又名 PBKDF1)的实现包括 insecure 扩展，以提供比散列函数所能提供的更多的字节(参见错误报告此处和这里).

Microsoft's implementation of original PKCS#5 (aka PBKDF1) include insecure extensions to provide more bytes than the hash function can provide (see bug reports here and here).

即使它没有错误，您也应该避免对标准进行未记录的专有扩展(否则您将来可能永远无法解密您的数据 - 至少不能在 Windows 之外.)

Even if it was not buggy you should avoid undocumented, proprietary extensions to standards (or you might never be able to decrypt your data in the future - at least not outside Windows.)

我强烈建议您使用更新的 Rfc2898DeriveBytes，它实现了自 .NET 2.0 起可用的 PBKDF2 (PKCS#5 v2).

I strongly suggest you to use the newer Rfc2898DeriveBytes which implements PBKDF2 (PKCS#5 v2) which is available since .NET 2.0.

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