在.NET中产生随机密码字符串

using System;using System.Security.Cryptography;using System.Text;namespace Utility {public class PasswordGenerator {public PasswordGenerator() {this.Minimum = DefaultMinimum;this.Maximum = DefaultMaximum;this.ConsecutiveCharacters = false;this.RepeatCharacters = true;this.ExcludeSymbols = false;this.Exclusions = null;rng = new RNGCryptoServiceProvider();}protected int GetCryptographicRandomNumber(int lBound, int uBound) {// 假定 lBound >= 0 && lBound < uBound// 返回一个 int >= lBound and < uBounduint urndnum;byte[] rndnum = new Byte[4];if (lBound == uBound-1) {// 只有iBound返回的情况return lBound;}uint xcludeRndBase = (uint.MaxValue - (uint.MaxValue%(uint)(uBound-lBound)));do {rng.GetBytes(rndnum);urndnum = System.BitConverter.ToUInt32(rndnum,0);} while (urndnum >= xcludeRndBase);return (int)(urndnum % (uBound-lBound)) + lBound;}protected char GetRandomCharacter() {int upperBound = pwdCharArray.GetUpperBound(0);if ( true == this.ExcludeSymbols ) {upperBound = PasswordGenerator.UBoundDigit;}int randomCharPosition = GetCryptographicRandomNumber(pwdCharArray.GetLowerBound(0), upperBound);char randomChar = pwdCharArray[randomCharPosition];return randomChar;}public string Generate() {// 得到minimum 和 maximum 之间随机的长度int pwdLength = GetCryptographicRandomNumber(this.Minimum, this.Maximum);StringBuilder pwdBuffer = new StringBuilder();pwdBuffer.Capacity = this.Maximum;// 产生随机字符char lastCharacter, nextCharacter;// 初始化标记lastCharacter = nextCharacter = '/n';for ( int i = 0; i < pwdLength; i++ ) {nextCharacter = GetRandomCharacter();if ( false == this.ConsecutiveCharacters ) {while ( lastCharacter == nextCharacter ) {nextCharacter = GetRandomCharacter();}}if ( false == this.RepeatCharacters ) {string temp = pwdBuffer.ToString();int duplicateIndex = temp.IndexOf(nextCharacter);while ( -1 != duplicateIndex ) {nextCharacter = GetRandomCharacter();duplicateIndex = temp.IndexOf(nextCharacter);}}if ( ( null != this.Exclusions ) ) {while ( -1 != this.Exclusions.IndexOf(nextCharacter) ) {nextCharacter = GetRandomCharacter();}}pwdBuffer.Append(nextCharacter);lastCharacter = nextCharacter;}if ( null != pwdBuffer ) {return pwdBuffer.ToString();}else {return String.Empty;}}public bool ConsecutiveCharacters {get { return this.hasConsecutive; }set { this.hasConsecutive = value;}}public bool ExcludeSymbols {get { return this.hasSymbols; }set { this.hasSymbols = value;}}public string Exclusions {get { return this.exclusionSet; }set { this.exclusionSet = value; }}public int Maximum {get { return this.maxSize; }set {this.maxSize = value;if ( this.minSize >= this.maxSize ) {this.maxSize = PasswordGenerator.DefaultMaximum;}}}public int Minimum {get { return this.minSize; }set {this.minSize = value;if ( PasswordGenerator.DefaultMinimum > this.minSize ) {this.minSize = PasswordGenerator.DefaultMinimum;}}}public bool RepeatCharacters {get { return this.hasRepeating; }set { this.hasRepeating = value;}}private const int DefaultMaximum = 10;private const int DefaultMinimum = 6;private const int UBoundDigit = 61;private string exclusionSet;private bool hasConsecutive;private bool hasRepeating;private bool hasSymbols;private int maxSize;private int minSize;private char[] pwdCharArray = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789`~!@#$^*()-_=+[]{}//|;:'/",./".ToCharArray();private RNGCryptoServiceProvider rng;}}