Public Class Cls_JM
'使用
'Dim Jm As New Cls_JM(2)
'Dim strTmp As String
'Jm.jiemi(strTmp)
'Jm.Jiami(strTmp)
Private TripleDes As New System.Security.Cryptography.TripleDESCryptoServiceProvider
Private Function TruncateHash(ByVal key As String, ByVal length As Integer) As Byte()
Dim sha1 As New System.Security.Cryptography.SHA1CryptoServiceProvider ' Hash the key.
Dim keyBytes() As Byte = System.Text.Encoding.Unicode.GetBytes(key)
Dim hash() As Byte = sha1.ComputeHash(keyBytes) ' Truncate or pad the hash.
ReDim Preserve hash(length - 1)
Return hash
End Function
Sub New(ByVal key As String) ' Initialize the crypto provider.
TripleDes.Key = TruncateHash(key, TripleDes.KeySize \ 8)
TripleDes.IV = TruncateHash("", TripleDes.BlockSize \ 8)
End Sub
Public Function jiami(ByVal plaintext As String) As String ' Convert the plaintext string to a byte array.
Dim plaintextBytes() As Byte = System.Text.Encoding.Unicode.GetBytes(plaintext) ' Create the stream.
Dim ms As New System.IO.MemoryStream ' Create the encoder to write to the stream.
Dim encStream As New System.Security.Cryptography.CryptoStream(ms, TripleDes.CreateEncryptor(), System.Security.Cryptography.CryptoStreamMode.Write) ' Use the crypto stream to write the byte array to the stream.
encStream.Write(plaintextBytes, 0, plaintextBytes.Length)
encStream.FlushFinalBlock() ' Convert the encrypted stream to a printable string.
Return Convert.ToBase64String(ms.ToArray)
End Function
Public Function jiemi(ByVal encryptedtext As String) As String ' Convert the encrypted text string to a byte array.
Dim encryptedBytes() As Byte = Convert.FromBase64String(encryptedtext) ' Create the stream.
Dim ms As New System.IO.MemoryStream ' Create the decoder to write to the stream.
Dim decStream As New System.Security.Cryptography.CryptoStream(ms, TripleDes.CreateDecryptor(), System.Security.Cryptography.CryptoStreamMode.Write) ' Use the crypto stream to write the byte array to the stream.
decStream.Write(encryptedBytes, 0, encryptedBytes.Length)
decStream.FlushFinalBlock() ' Convert the plaintext stream to a string.
Return System.Text.Encoding.Unicode.GetString(ms.ToArray)
End Function
End Class
