驗證碼是現在管理系統常用的一種保護用戶帳戶信息的一種功能。
驗證碼可以有效防止某個黑客對某一個特定注冊用戶用特定程序暴力破解方式進行不斷的登錄嘗試，雖然這可能是我們登錄麻煩一點，但是對用戶的密碼安全來說這個功能還是很有必要，也很重要。但在這裡我還是要提醒大家要保護好自己的密碼同時盡量使自己的密碼復雜度高一點，免得你的賬號被人盜用後給自己帶來不必要的麻煩。
現在使用的驗證碼類是蘇飛論壇的蘇飛所寫，本人只是學習和使用而已，驗證碼類如下所示：
/// <summary>
/// 類說明：YZMHelper
/// 編 碼 人：蘇飛
/// 聯系方式：361983679
/// 更新網站：http://www.sufeinet.com/thread-655-1-1.html
/// </summary>
using System;
using System.Web;
using System.Drawing;
using System.Security.Cryptography;
namespace DotNet.Utilities
{
/// <summary>
/// 驗證碼類
/// </summary>
public class Rand
{
#region 生成隨機數字
/// <summary>
/// 生成隨機數字
/// </summary>
/// <param name="length">生成長度</param>
public static string Number(int Length)
{
return Number(Length, false);
}
/// <summary>
/// 生成隨機數字
/// </summary>
/// <param name="Length">生成長度</param>
/// <param name="Sleep">是否要在生成前將當前線程阻止以避免重復</param>
public static string Number(int Length, bool Sleep)
{
if (Sleep) System.Threading.Thread.Sleep(3);
string result = "";
System.Random random = new Random();
for (int i = 0; i < Length; i++)
{
result += random.Next(10).ToString();
}
return result;
}
#endregion
#region 生成隨機字母與數字
/// <summary>
/// 生成隨機字母與數字
/// </summary>
/// <param name="IntStr">生成長度</param>
public static string Str(int Length)
{
return Str(Length, false);
}
/// <summary>
/// 生成隨機字母與數字
/// </summary>
/// <param name="Length">生成長度</param>
/// <param name="Sleep">是否要在生成前將當前線程阻止以避免重復</param>
public static string Str(int Length, bool Sleep)
{
if (Sleep) System.Threading.Thread.Sleep(3);
char[] Pattern = new char[] { '0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
string result = "";
int n = Pattern.Length;
System.Random random = new Random(~unchecked((int)DateTime.Now.Ticks));
for (int i = 0; i < Length; i++)
{
int rnd = random.Next(0, n);
result += Pattern[rnd];
}
return result;
}
#endregion
#region 生成隨機純字母隨機數
/// <summary>
/// 生成隨機純字母隨機數
/// </summary>
/// <param name="IntStr">生成長度</param>
public static string Str_char(int Length)
{
return Str_char(Length, false);
}
/// <summary>
/// 生成隨機純字母隨機數
/// </summary>
/// <param name="Length">生成長度</param>
/// <param name="Sleep">是否要在生成前將當前線程阻止以避免重復</param>
public static string Str_char(int Length, bool Sleep)
{
if (Sleep) System.Threading.Thread.Sleep(3);
char[] Pattern = new char[] { 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z' };
string result = "";
int n = Pattern.Length;
System.Random random = new Random(~unchecked((int)DateTime.Now.Ticks));
for (int i = 0; i < Length; i++)
{
int rnd = random.Next(0, n);
result += Pattern[rnd];
}
return result;
}
#endregion
}
/// <summary>
/// 驗證圖片類
/// </summary>
public class YZMHelper
{
#region 私有字段
private string text;
private Bitmap image;
private int letterCount = 4; //驗證碼位數
private int letterWidth = 16; //單個字體的寬度范圍
private int letterHeight = 20; //單個字體的高度范圍
private static byte[] randb = new byte[4];
private static RNGCryptoServiceProvider rand = new RNGCryptoServiceProvider();
private Font[] fonts =
{
new Font(new FontFamily("Times New Roman"),10 +Next(1),System.Drawing.FontStyle.Regular),
new Font(new FontFamily("Georgia"), 10 + Next(1),System.Drawing.FontStyle.Regular),
new Font(new FontFamily("Arial"), 10 + Next(1),System.Drawing.FontStyle.Regular),
new Font(new FontFamily("Comic Sans MS"), 10 + Next(1),System.Drawing.FontStyle.Regular)
};
#endregion
#region 公有屬性
/// <summary>
/// 驗證碼
/// </summary>
public string Text
{
get { return this.text; }
}
/// <summary>
/// 驗證碼圖片
/// </summary>
public Bitmap Image
{
get { return this.image; }
}
#endregion
#region 構造函數
public YZMHelper()
{
HttpContext.Current.Response.Expires = 0;
HttpContext.Current.Response.Buffer = true;
HttpContext.Current.Response.ExpiresAbsolute = DateTime.Now.AddSeconds(-1);
HttpContext.Current.Response.AddHeader("pragma", "no-cache");
HttpContext.Current.Response.CacheControl = "no-cache";
this.text = Rand.Number(4);
CreateImage();
}
#endregion
#region 私有方法
/// <summary>
/// 獲得下一個隨機數
/// </summary>
/// <param name="max">最大值</param>
private static int Next(int max)
{
rand.GetBytes(randb);
int value = BitConverter.ToInt32(randb, 0);
value = value % (max + 1);
if (value < 0) value = -value;
return value;
}
/// <summary>
/// 獲得下一個隨機數
/// </summary>
/// <param name="min">最小值</param>
/// <param name="max">最大值</param>
private static int Next(int min, int max)
{
int value = Next(max - min) + min;
return value;
}
#endregion
#region 公共方法
/// <summary>
/// 繪制驗證碼
/// </summary>
public void CreateImage()
{
int int_ImageWidth = this.text.Length * letterWidth;
Bitmap image = new Bitmap(int_ImageWidth, letterHeight);
Graphics g = Graphics.FromImage(image);
g.Clear(Color.White);
for (int i = 0; i < 2; i++)
{
int x1 = Next(image.Width - 1);
int x2 = Next(image.Width - 1);
int y1 = Next(image.Height - 1);
int y2 = Next(image.Height - 1);
g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
int _x = -12, _y = 0;
for (int int_index = 0; int_index < this.text.Length; int_index++)
{
_x += Next(12, 16);
_y = Next(-2, 2);
string str_char = this.text.Substring(int_index, 1);
str_char = Next(1) == 1 ? str_char.ToLower() : str_char.ToUpper();
Brush newBrush = new SolidBrush(GetRandomColor());
Point thePos = new Point(_x, _y);
g.DrawString(str_char, fonts[Next(fonts.Length - 1)], newBrush, thePos);
}
for (int i = 0; i < 10; i++)
{
int x = Next(image.Width - 1);
int y = Next(image.Height - 1);
image.SetPixel(x, y, Color.FromArgb(Next(0, 255), Next(0, 255), Next(0, 255)));
}
image = TwistImage(image, true, Next(1, 3), Next(4, 6));
g.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, int_ImageWidth - 1, (letterHeight - 1));
this.image = image;
}
/// <summary>
/// 字體隨機顏色
/// </summary>
public Color GetRandomColor()
{
Random RandomNum_First = new Random((int)DateTime.Now.Ticks);
System.Threading.Thread.Sleep(RandomNum_First.Next(50));
Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);
int int_Red = RandomNum_First.Next(180);
int int_Green = RandomNum_Sencond.Next(180);
int int_Blue = (int_Red + int_Green > 300) ? 0 : 400 - int_Red - int_Green;
int_Blue = (int_Blue > 255) ? 255 : int_Blue;
return Color.FromArgb(int_Red, int_Green, int_Blue);
}
/// <summary>
/// 正弦曲線Wave扭曲圖片
/// </summary>
/// <param name="srcBmp">圖片路徑</param>
/// <param name="bXDir">如果扭曲則選擇為True</param>
/// <param name="nMultValue">波形的幅度倍數，越大扭曲的程度越高,一般為3</param>
/// <param name="dPhase">波形的起始相位,取值區間[0-2*PI)</param>
public System.Drawing.Bitmap TwistImage(Bitmap srcBmp, bool bXDir, double dMultValue, double dPhase)
{
double PI = 6.283185307179586476925286766559;
Bitmap destBmp = new Bitmap(srcBmp.Width, srcBmp.Height);
Graphics graph = Graphics.FromImage(destBmp);
graph.FillRectangle(new SolidBrush(Color.White), 0, 0, destBmp.Width, destBmp.Height);
graph.Dispose();
double dBaseAxisLen = bXDir ? (double)destBmp.Height : (double)destBmp.Width;
for (int i = 0; i < destBmp.Width; i++)
{
for (int j = 0; j < destBmp.Height; j++)
{
double dx = 0;
dx = bXDir ? (PI * (double)j) / dBaseAxisLen : (PI * (double)i) / dBaseAxisLen;
dx += dPhase;
double dy = Math.Sin(dx);
int nOldX = 0, nOldY = 0;
nOldX = bXDir ? i + (int)(dy * dMultValue) : i;
nOldY = bXDir ? j : j + (int)(dy * dMultValue);
Color color = srcBmp.GetPixel(i, j);
if (nOldX >= 0 && nOldX < destBmp.Width
&& nOldY >= 0 && nOldY < destBmp.Height)
{
destBmp.SetPixel(nOldX, nOldY, color);
}
}
}
srcBmp.Dispose();
return destBmp;
}
#endregion
}
}
大家一起交流哈，雖然驗證碼本身實現很簡單，但是像上面封裝成靈活好用的幫助類還是不多見的，蘇飛大神這種代碼的規范性上值得個人去學習。
這個東西沒有通用性，同一個驗證碼識別都不准確，更別說類庫了。
這個安裝了VS2010後就會有！
