Code:
/ DotNET / DotNET / 8.0 / untmp / whidbey / REDBITS / ndp / clr / src / BCL / System / Security / Cryptography / PasswordDeriveBytes.cs / 1 / PasswordDeriveBytes.cs
// ==++== // // Copyright (c) Microsoft Corporation. All rights reserved. // // ==--== // // PasswordDerivedBytes.cs // namespace System.Security.Cryptography { using System.IO; using System.Runtime.CompilerServices; using System.Security.Cryptography.X509Certificates; using System.Text; using System.Globalization; [System.Runtime.InteropServices.ComVisible(true)] public class PasswordDeriveBytes : DeriveBytes { private int _extraCount; private int _prefix; private int _iterations; private byte[] _baseValue; private byte[] _extra; private byte[] _salt; private string _hashName; private byte[] _password; private HashAlgorithm _hash; private CspParameters _cspParams; private SafeProvHandle _safeProvHandle = null; private SafeProvHandle ProvHandle { get { if (_safeProvHandle == null) { lock (this) { if (_safeProvHandle == null) { SafeProvHandle safeProvHandle = Utils.AcquireProvHandle(_cspParams); System.Threading.Thread.MemoryBarrier(); _safeProvHandle = safeProvHandle; } } } return _safeProvHandle; } } // // public constructors // public PasswordDeriveBytes (String strPassword, byte[] rgbSalt) : this (strPassword, rgbSalt, new CspParameters()) {} public PasswordDeriveBytes (byte[] password, byte[] salt) : this (password, salt, new CspParameters()) {} public PasswordDeriveBytes (string strPassword, byte[] rgbSalt, string strHashName, int iterations) : this (strPassword, rgbSalt, strHashName, iterations, new CspParameters()) {} public PasswordDeriveBytes (byte[] password, byte[] salt, string hashName, int iterations) : this (password, salt, hashName, iterations, new CspParameters()) {} public PasswordDeriveBytes (string strPassword, byte[] rgbSalt, CspParameters cspParams) : this (strPassword, rgbSalt, "SHA1", 100, cspParams) {} public PasswordDeriveBytes (byte[] password, byte[] salt, CspParameters cspParams) : this (password, salt, "SHA1", 100, cspParams) {} public PasswordDeriveBytes (string strPassword, byte[] rgbSalt, String strHashName, int iterations, CspParameters cspParams) : this ((new UTF8Encoding(false)).GetBytes(strPassword), rgbSalt, strHashName, iterations, cspParams) {} public PasswordDeriveBytes (byte[] password, byte[] salt, String hashName, int iterations, CspParameters cspParams) { this.IterationCount = iterations; this.Salt = salt; this.HashName = hashName; _password = password; _cspParams = cspParams; } // // public properties // public String HashName { get { return _hashName; } set { if (_baseValue != null) throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_PasswordDerivedBytes_ValuesFixed"), "HashName")); _hashName = value; _hash = (HashAlgorithm) CryptoConfig.CreateFromName(_hashName); } } public int IterationCount { get { return _iterations; } set { if (_baseValue != null) throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_PasswordDerivedBytes_ValuesFixed"), "IterationCount")); if (value <= 0) throw new ArgumentOutOfRangeException("value", Environment.GetResourceString("ArgumentOutOfRange_NeedNonNegNum")); _iterations = value; } } public byte[] Salt { get { if (_salt == null) return null; return (byte[]) _salt.Clone(); } set { if (_baseValue != null) throw new CryptographicException(String.Format(CultureInfo.CurrentCulture, Environment.GetResourceString("Cryptography_PasswordDerivedBytes_ValuesFixed"), "Salt")); if (value == null) _salt = null; else _salt = (byte[]) value.Clone(); } } // // public methods // [Obsolete("Rfc2898DeriveBytes replaces PasswordDeriveBytes for deriving key material from a password and is preferred in new applications.")] public override byte[] GetBytes(int cb) { int ib = 0; byte[] rgb; byte[] rgbOut = new byte[cb]; if (_baseValue == null) { ComputeBaseValue(); } else if (_extra != null) { ib = _extra.Length - _extraCount; if (ib >= cb) { Buffer.InternalBlockCopy(_extra, _extraCount, rgbOut, 0, cb); if (ib > cb) _extraCount += cb; else _extra = null; return rgbOut; } else { // // Note: The second parameter should really be _extraCount instead // However, changing this would constitute a breaking change compared // to what has shipped in V1.x. // Buffer.InternalBlockCopy(_extra, ib, rgbOut, 0, ib); _extra = null; } } rgb = ComputeBytes(cb-ib); Buffer.InternalBlockCopy(rgb, 0, rgbOut, ib, cb-ib); if (rgb.Length + ib > cb) { _extra = rgb; _extraCount = cb-ib; } return rgbOut; } public override void Reset() { _prefix = 0; _extra = null; _baseValue = null; } public byte[] CryptDeriveKey (string algname, string alghashname, int keySize, byte[] rgbIV) { if (keySize < 0) throw new CryptographicException(Environment.GetResourceString("Cryptography_InvalidKeySize")); int algidhash = X509Utils.OidToAlgId(alghashname); if (algidhash == 0) throw new CryptographicException(Environment.GetResourceString("Cryptography_PasswordDerivedBytes_InvalidAlgorithm")); int algid = X509Utils.OidToAlgId(algname); if (algid == 0) throw new CryptographicException(Environment.GetResourceString("Cryptography_PasswordDerivedBytes_InvalidAlgorithm")); // Validate the rgbIV array if (rgbIV == null) throw new CryptographicException(Environment.GetResourceString("Cryptography_PasswordDerivedBytes_InvalidIV")); return Utils._CryptDeriveKey(ProvHandle, algid, algidhash, _password, keySize << 16, rgbIV); } // // private methods // private byte[] ComputeBaseValue() { _hash.Initialize(); _hash.TransformBlock(_password, 0, _password.Length, _password, 0); if (_salt != null) _hash.TransformBlock(_salt, 0, _salt.Length, _salt, 0); _hash.TransformFinalBlock(new byte[0], 0, 0); _baseValue = _hash.Hash; _hash.Initialize(); for (int i=1; i<(_iterations-1); i++) { _hash.ComputeHash(_baseValue); _baseValue = _hash.Hash; } return _baseValue; } private byte[] ComputeBytes(int cb) { int cbHash; int ib = 0; byte[] rgb; _hash.Initialize(); cbHash = _hash.HashSize / 8; rgb = new byte[((cb+cbHash-1)/cbHash)*cbHash]; CryptoStream cs = new CryptoStream(Stream.Null, _hash, CryptoStreamMode.Write); HashPrefix(cs); cs.Write(_baseValue, 0, _baseValue.Length); cs.Close(); Buffer.InternalBlockCopy(_hash.Hash, 0, rgb, ib, cbHash); ib += cbHash; while (cb > ib) { _hash.Initialize(); cs = new CryptoStream(Stream.Null, _hash, CryptoStreamMode.Write); HashPrefix(cs); cs.Write(_baseValue, 0, _baseValue.Length); cs.Close(); Buffer.InternalBlockCopy(_hash.Hash, 0, rgb, ib, cbHash); ib += cbHash; } return rgb; } void HashPrefix(CryptoStream cs) { int cb = 0; byte[] rgb = {(byte)'0', (byte)'0', (byte)'0'}; if (_prefix > 999) throw new CryptographicException(Environment.GetResourceString("Cryptography_PasswordDerivedBytes_TooManyBytes")); if (_prefix >= 100) { rgb[0] += (byte) (_prefix /100); cb += 1; } if (_prefix >= 10) { rgb[cb] += (byte) ((_prefix % 100) / 10); cb += 1; } if (_prefix > 0) { rgb[cb] += (byte) (_prefix % 10); cb += 1; cs.Write(rgb, 0, cb); } _prefix += 1; } } }
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