加密算法(包含证书)加密解密签名验签

什么是对称加密和非对称加密？
对称加密是指：有一个密钥，加密用它来加密，解密也需要用到它。因为加密解密都是用同一个密钥所以叫对称加密。
非对称加密是指：就是有 2 个密钥，一个是公钥，一个是私钥。私钥是自己的，不能随便给人，公钥随便给，无所谓。一般是别人用你的公钥加密，然后把密文给你，你用你的私钥解密，这样一样加密和解密不是同一个密钥，所以叫非对称。

对称和非对称的优劣？
对称加密有一个坏处只要拥有密钥的人都可以解密。
非对称的好处是假如没有私钥，别人是无法解密的，就算加密的那个人他把数据加密了他也无法解密，加密者把密文和公钥随便给那个人都无法解密。

什么是数字签名？
数字签名是指：用一段密码与原文进行加密，检测原文有没有被 篡改。意义就是这些数据与原文数据比对是否修改过，这个解释有点麻烦，一般是用自己的私钥对数据进行签名，然后用公钥去验证这个数据是否修改过
1、用 RSACryptoServiceProvider 加密解密
'要加密的数据  
Dim messageBytes As Byte() = Text.Encoding.UTF8.GetBytes('激情燃烧的木炭[http://www.woodcoal.cn/]')  
 
'1. 产生公匙和私匙,两个数据都要保存  
Dim oRsa As New Security.Cryptography.RSACryptoServiceProvider  
Dim privateKey As String = oRsa.ToXmlString(True)  
Dim publicKey As String = oRsa.ToXmlString(False)  
 
'2. 用公匙加密数据  
Dim oRsaEncode As New Security.Cryptography.RSACryptoServiceProvider  
'导入公匙  
oRsaEncode.FromXmlString(publicKey)  
'输出加密后的数据  
Dim resultByte As Byte() = oRsaEncode.Encrypt(messageBytes, False)  
 
'3. 用私匙解密数据  
Dim oRsaDecode As New Security.Cryptography.RSACryptoServiceProvider  
'导入私匙  
oRsaDecode.FromXmlString(privateKey)  
'输出解密后的数据  
messageBytes = oRsaDecode.Decrypt(resultByte, False)  
 
'结果  
Return Text.Encoding.UTF8.GetString(messageBytes) 


2、用 RSACryptoServiceProvider 签名验签
'要加密的数据  
Dim messageBytes As Byte() = Text.Encoding.UTF8.GetBytes('激情燃烧的木炭[http://www.woodcoal.cn/]')  
 
'1. 产生公匙和私匙,两个数据都要保存  
Dim oRsa As New Security.Cryptography.RSACryptoServiceProvider  
Dim privateKey As String = oRsa.ToXmlString(True)  
Dim publicKey As String = oRsa.ToXmlString(False)  
 
'2. 用私钥匙签名数据  
Dim oRsaEncode As New Security.Cryptography.RSACryptoServiceProvider  
'导入私钥  
oRsaEncode.FromXmlString(privateKey)  
'输出签名后的数据  
Dim resultByte As Byte() = oRsaEncode.SignData(messageBytes, 'SHA1')  
 
'3. 用公钥验证数据  
Dim oRsaDecode As New Security.Cryptography.RSACryptoServiceProvider  
'导入公钥  
oRsaDecode.FromXmlString(publicKey)  
'输出验证后的结果，是否验证成功  
Return oRsaDecode.VerifyData(resultByte, 'SHA1', messageBytes) 

3、用证书进行签名
因为一般证书的私钥是不可以导出的，所以用第 2 种方法导入私钥的来进行签名行不通。
'要加密的数据  
Dim messageBytes As Byte() = Text.Encoding.UTF8.GetBytes('激情燃烧的木炭[http://www.woodcoal.cn/]')  
Dim certificatePath As String = 'E:\Certificate.P12' 
 
'导入证书  
Dim x509 As New Security.Cryptography.X509Certificates.X509Certificate2(certificatePath, 'Import Password')  
Dim privateKey As Security.Cryptography.RSACryptoServiceProvider = x509.PrivateKey  
Dim publicKey As String = x509.PublicKey.Key.ToXmlString(False)  
 
'对要签名的数据进行哈希  
Dim sha1 As New Security.Cryptography.SHA1CryptoServiceProvider  
Dim hashBytes As Byte() = sha1.ComputeHash(messageBytes)  
 
'签名对象  
Dim signe As New Security.Cryptography.RSAPKCS1SignatureFormatter  
'设置签名用到的私钥   
signe.SetKey(privateKey)  
'设置签名算法   
signe.SetHashAlgorithm('SHA1')  
'返回结果  
Dim reslutBytes As Byte() = signe.CreateSignature(hashBytes)  
 
 
'3. 用公钥验证数据,与第2方法相同  
Dim oRsaDecode As New Security.Cryptography.RSACryptoServiceProvider  
'导入公钥  
oRsaDecode.FromXmlString(publicKey)  
'输出验证后的结果，是否验证成功  
Return oRsaDecode.VerifyData(resultByte, 'SHA1', messageBytes) 


4、用证书加密解密
'要加密的数据  
Dim messageBytes As Byte() = Text.Encoding.UTF8.GetBytes('激情燃烧的木炭[http://www.woodcoal.cn/]')  
Dim certificatePath As String = 'E:\Certificate.P12' 
 
'导入证书  
Dim x509 As New Security.Cryptography.X509Certificates.X509Certificate2(certificatePath, 'Import Password')  
Dim privateKey As Security.Cryptography.RSACryptoServiceProvider = x509.PrivateKey  
Dim publicKey As String = x509.PublicKey.Key.ToXmlString(False)  
 
'证书公钥加密  
Dim oRsaEncode As New Security.Cryptography.RSACryptoServiceProvider  
oRsaEncode.FromXmlString(publicKey)  
Dim resultBytes As Byte() = oRsaEncode.Encrypt(messageBytes, False)  
 
'证书私钥解密   
Dim oRsaDecode As Security.Cryptography.RSACryptoServiceProvider = DirectCast(privateKey, Security.Cryptography.RSACryptoServiceProvider)  
messageBytes = oRsaDecode.Decrypt(resultBytes, False)  
 
'返回结果  
Return Text.Encoding.UTF8.GetString(messageBytes) 

5、用证书对文件加密解密
因为文件可能特别大 所以需要用流和 Buffer 的方式，如果把文件全部读到 Byte() 里进行加密，当文件很大，比如 5G，那全部读到 Byte() 里崩溃掉
''' 用证书加密文件  
''' 证书路径  
''' 证书导入密码  
''' 需要加密的文件路径  
''' 加密后的文件路径  
'''   
Public Sub Encrypt(ByVal certificatePath As String, ByVal certificatePassword As String, ByVal sourcePath As String, ByVal targetPath As String)  
    '导入证书  
    Dim x509 As New Security.Cryptography.X509Certificates.X509Certificate2(certificatePath, certificatePassword)  
    'Dim privateKey As Security.Cryptography.RSACryptoServiceProvider = x509.PrivateKey  
    Dim publicKey As String = x509.PublicKey.Key.ToXmlString(False)  
 
    Dim oRsa As New Security.Cryptography.RSACryptoServiceProvider()  
    oRsa.FromXmlString(publicKey)  
    Dim sourceStream As New System.IO.FileStream(sourcePath, System.IO.FileMode.Open)  
    Dim targetStream As New System.IO.FileStream(targetPath, System.IO.FileMode.OpenOrCreate)  
 
    Dim blockSize As Integer = 0  
    If oRsa.KeySize = 1024 Then 
        blockSize = 16  
    Else 
        blockSize = 8  
    End If 
 
    Dim K As Integer = 1  
    While K > 0  
        Dim buffer As Byte() = New Byte(blockSize - 1) {}  
 
        K = sourceStream.Read(buffer, 0, buffer.Length)  
        If K > 0 Then 
            Dim buffer1 As Byte(), encryblock As Byte()  
            If blockSize = K Then 
                encryblock = oRsa.Encrypt(buffer, False)  
                targetStream.Write(encryblock, 0, encryblock.Length)  
            Else 
                buffer1 = New Byte(K - 1) {}  
                For i As Integer = 0 To K - 1  
                    buffer1(i) = buffer(i)  
                Next 
                encryblock = oRsa.Encrypt(buffer1, False)  
                targetStream.Write(encryblock, 0, encryblock.Length)  
            End If 
        Else 
            sourceStream.Close()  
            targetStream.Close()  
        End If 
    End While 
End Sub 
 
''' 用证书解密文件  
''' 证书路径  
''' 证书导入密码  
''' 需要解密的文件路径  
''' 解密后的文件路径  
'''   
Public Sub Decrypt(ByVal certificatePath As String, ByVal certificatePassword As String, ByVal sourcePath As String, ByVal targetPath As String)  
    '导入证书  
    Dim x509 As New Security.Cryptography.X509Certificates.X509Certificate2(certificatePath, certificatePassword)  
    Dim privateKey As Security.Cryptography.RSACryptoServiceProvider = x509.PrivateKey  
    'Dim publicKey As String = x509.PublicKey.Key.ToXmlString(False)  
 
    Dim oRsa As Security.Cryptography.RSACryptoServiceProvider = DirectCast(privateKey, Security.Cryptography.RSACryptoServiceProvider)  
    Dim sourceStream As New System.IO.FileStream(sourcePath, System.IO.FileMode.Open)  
    Dim targetStream As New System.IO.FileStream(targetPath, System.IO.FileMode.OpenOrCreate)  
 
    Dim blockSize As Integer = oRsa.KeySize / 8  
    Dim buffer1 As Byte(), encryblock As Byte()  
 
    Dim K As Integer = 1  
    While K > 0  
        Dim buffer As Byte() = New Byte(blockSize - 1) {}  
        K = sourceStream.Read(Buffer, 0, Buffer.Length)  
        If K > 0 Then 
            If blockSize = K Then 
                encryblock = oRsa.Decrypt(buffer, False)  
                targetStream.Write(encryblock, 0, encryblock.Length)  
            Else 
                buffer1 = New Byte(K - 1) {}  
                For i As Integer = 0 To K - 1  
                    buffer1(i) = buffer(i)  
                Next 
                encryblock = oRsa.Decrypt(buffer1, False)  
                targetStream.Write(encryblock, 0, encryblock.Length)  
            End If 
        Else 
            sourceStream.Close()  
            targetStream.Close()  
        End If 
    End While 
End Sub 


6、用证书对文件进行签名验签
Private Sub Form1_Load(ByVal sender As Object, ByVal e As EventArgs)   
    x509 = New X509Certificate2(Path, '12345678')   
    SignFile('1.txt', '11.txt')   
      
    VerifyFile('1.txt', '11.txt')   
End Sub   
Private Function VerifyFile(ByVal FileName As String, ByVal SignedFileName As String) As Boolean   
      
    Dim reslut As Boolean = True   
      
    Dim objread As New System.IO.StreamReader(FileName)   
    Dim objreadSigned As New System.IO.StreamReader(SignedFileName)   
      
    Dim VeryRsa As New RSACryptoServiceProvider()   
    VeryRsa.FromXmlString(x509.PublicKey.Key.ToXmlString(False))   
      
    Dim Inblocksize As Integer = 0   
    Dim Signedblocksize As Integer = 0   
    If VeryRsa.KeySize = 1024 Then   
        Inblocksize = 16   
    Else   
        Inblocksize = 8   
    End If   
    Signedblocksize = VeryRsa.KeySize / 8   
      
    Dim Closed As Boolean = True   
    Dim Buffer As Byte()   
    '原文缓存区   
    Dim InBuffer As Byte()   
    '原文缓存区   
    Dim Buffer1 As Byte()   
    '签名文件缓存区   
    While Closed   
        Buffer = Nothing   
        Buffer = New Byte(Inblocksize - 1) {}   
        Dim k As Integer = objread.BaseStream.Read(Buffer, 0, Buffer.Length)   
        If k > 0 Then   
            If Inblocksize = k Then   
                '读出来的长度和缓存区一样大   
                Buffer1 = New Byte(Signedblocksize - 1) {}   
                objreadSigned.BaseStream.Read(Buffer1, 0, Buffer1.Length)   
                reslut = VeryRsa.VerifyData(Buffer, 'SHA1', Buffer1)   
                If Not reslut Then   
                    Closed = False   
                End If   
            Else   
                '意思是Buffer没满，只有k个字节，k字节后面全是空所以不需要验签   
                InBuffer = New Byte(k - 1) {}   
                For i As Integer = 0 To k - 1   
                    InBuffer(i) = Buffer(i)   
                Next   
                Buffer1 = New Byte(Signedblocksize - 1) {}   
                objreadSigned.BaseStream.Read(Buffer1, 0, Buffer1.Length)   
                reslut = VeryRsa.VerifyData(InBuffer, 'SHA1', Buffer1)   
                If Not reslut Then   
                    Closed = False   
                End If   
            End If   
        Else   
            '这里的意思是原文已经读完毕了，并且已经和签名文件对应验签成功，那么   
            '签名文件也必须读完毕了。   
            If objreadSigned.BaseStream.Position <> objreadSigned.BaseStream.Length Then   
                reslut = False   
            End If   
            objreadSigned.Close()   
            objread.Close()   
            Closed = False   
        End If   
    End While   
    Return reslut   
      
      
End Function   
Private Sub SignFile(ByVal InFileName As String, ByVal OutFileName As String)   
    Dim SignRsa As RSACryptoServiceProvider = DirectCast(x509.PrivateKey, RSACryptoServiceProvider)   
      
    Dim objread As New System.IO.StreamReader(InFileName)   
    Dim objwrite As New System.IO.StreamWriter(OutFileName, False)   
      
    Dim blocksize As Integer = 0   
    If SignRsa.KeySize = 1024 Then   
        blocksize = 16   
    Else   
        blocksize = 8   
    End If   
      
    Dim Closed As Boolean = True   
    Dim Buffer As Byte() = New Byte(blocksize - 1) {}   
    Dim buffer1 As Byte(), SignBytes As Byte()   
    While Closed   
        Dim k As Integer = objread.BaseStream.Read(Buffer, 0, Buffer.Length)   
        If k > 0 Then   
            If k = blocksize Then   
                SignBytes = SignRsa.SignData(Buffer, 'SHA1')   
                objwrite.BaseStream.Write(SignBytes, 0, SignBytes.Length)   
            Else   
                buffer1 = New Byte(k - 1) {}   
                For i As Integer = 0 To k - 1   
                    buffer1(i) = Buffer(i)   
                Next   
                SignBytes = SignRsa.SignData(buffer1, 'SHA1')   
                objwrite.BaseStream.Write(SignBytes, 0, SignBytes.Length)   
            End If   
        Else   
            Closed = False   
            objread.Close()   
            objwrite.Close()   
        End If   
    End While   
      
      
End Sub  

原文来源：“激情燃烧的木炭” http://www.woodcoal.cn/
原文标题：非对称加密算法(包含证书)加密解密签名验签 - Visual Basic[激情燃烧的木炭]
原文地址：http://www.woodcoal.cn/technology/visual-basic/2009331-18230-14.html