MD5加密字符串的实现方法介绍
使用方法：
16位长度的md5加密 ,如： MD5("lob.cn",16)
32位长度的md5加密 ,如： MD5("lob.cn",32)
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Imports System.Security.Cryptography
Imports System.Text
Private Function MD5(ByVal StrSource As String, ByVal Code As Int16) As String
‘这里用的是ascii编码密码原文，如果要用汉字做密码，可以用UnicodeEncoding，但会与ASP中的MD5函数不兼容
Dim DataToHash As Byte() = (New System.Text.ASCIIEncoding).GetBytes(StrSource)
Dim Hashvalue As Byte() = CType(System.Security.Cryptography.CryptoConfig.CreateFromName("MD5"), System.Security.Cryptography.HashAlgorithm).ComputeHash(DataToHash)
Dim i As Integer
Dim Str_MD5 As String = ""
Select Case Code
Case 16 ‘选择16位字符的加密结果
For i = 4 To 11
Str_MD5 += Hex(Hashvalue(i)).ToLower
Next
Case Else ‘Code错误时或者选择32位字符加密时，返回全部字符串，即32位字符
For i = 0 To Hashvalue.Length - 1
Str_MD5 += Hex(Hashvalue(i)).ToLower
Next
End Select
MD5 = Str_MD5
End Function
方法二（2009-07-29在csdn论坛上看到，乐博网补充上去，虽然是换汤不换药...）：
导入名空间
- VB.NET code
-
Imports System.Text Imports System.Security.Cryptography
-
代码如下：
Private Function SetMd5Pass(ByVal InPutString As String) As String
Dim Key As MD5 = MD5.Create
Dim Bytes() As Byte = Key.ComputeHash(Encoding.Default.GetBytes(InPutString))
Dim Sbuilter As New StringBuilder
For i As Integer = 0 To Bytes.Length - 1
Sbuilter.Append(Bytes(i).ToString("x2"))
Next
Return Sbuilter.ToString
End Function
1 Private Function SetMd5Pass(ByVal InPutString As String) As String
2 Dim Key As MD5 = MD5.Create
3 Dim Bytes() As Byte = Key.ComputeHash(Encoding.Default.GetBytes(InPutString))
4 Dim Sbuilter As New StringBuilder
5 For i As Integer = 0 To Bytes.Length - 1
6 Sbuilter.Append(Bytes(i).ToString("x2"))
7 Next
8 Return Sbuilter.ToString
9 End Function