RSACryptoServiceProvider 类，不是已经提供了生成方法了么

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1、生成独一无二的密钥

Dim rsa As New System.Security.Cryptography.RSACryptoServiceProvider()
Using writer As New IO.StreamWriter("d:\\test\\PrivateKey.xml")
writer.WriteLine(rsa.ToXmlString(True))
End Using
Using writer As New IO.StreamWriter("d:\\test\\PublicKey.xml")
writer.WriteLine(rsa.ToXmlString(False))
End Using

2、对文件进行加密

\'读取文件
Dim file As new IO.FileStream("d:\\test\\test.txt", IO.FileMode.Open)
Dim data(file.Length-1) As Byte
file.Read(data, 0, data.Length)
file.Close ()
\'加密
Dim oRSA As New System.Security.Cryptography.RSACryptoServiceProvider()
Dim sr As New IO.StreamReader("d:\\test\\PublicKey.xml")
Dim publickey = sr.ReadToEnd
sr.Close()
oRSA.FromXmlString(publickey)
Dim AOutput As Byte() = oRSA.Encrypt(data ,False)
\'生成加密文件
file = new IO.FileStream("d:\\test\\test加密.txt", IO.FileMode.Create)
file.Write(AOutput, 0, AOutput.Length)
file.Flush()
file.Close()

3、对加密文件进行加密

\'读取文件
Dim file As new IO.FileStream("d:\\test\\test加密.txt", IO.FileMode.Open)
Dim data(file.Length-1) As Byte
file.Read(data, 0, data.Length)
file.Close ()
\'解密
Dim oRSA As New System.Security.Cryptography.RSACryptoServiceProvider()
Dim sr As New IO.StreamReader("d:\\test\\PrivateKey.xml")
Dim PrivateKey = sr.ReadToEnd
sr.Close()
oRSA.FromXmlString(PrivateKey)
Dim AInput As Byte() = oRSA.Decrypt(data ,False)
\'生成加密文件
file = new IO.FileStream("d:\\test\\test解密.txt", IO.FileMode.Create)
file.Write(AInput, 0, AInput.Length)
file.Flush()
file.Close()

 我是一次性获取，大文件的话，一段一段的获取、加密、写入

分段加密处理

\'获取key
Dim oRSA As New System.Security.Cryptography.RSACryptoServiceProvider()
Dim sr As New IO.StreamReader("d:\\test\\PublicKey.xml")
Dim publickey = sr.ReadToEnd
sr.Close()
oRSA.FromXmlString(publickey)

\'读取和写入文件文件
Dim read As new IO.FileStream("d:\\test\\test.txt", IO.FileMode.Open)
Dim maxLength As Integer = oRSA.KeySize/8-11
Dim data(maxlength-1) As Byte
Dim write As new IO.FileStream("d:\\test\\test加密.txt", IO.FileMode.Create)
Dim dataSize As Integer = read.Read(data, 0, data.Length)
Do While dataSize = maxLength
    Dim AOutput As Byte() = oRSA.Encrypt(data ,False)
    write.Write(AOutput, 0, AOutput.Length)
    write.Flush()
    dataSize = read.Read(data, 0, data.Length)
    If dataSize < maxLength
        \'最后一次的情况
        Dim lsData(dataSize-1) As Byte
        Array.Copy(data, 0, lsData, 0, dataSize)
        Dim lsAOutput As Byte() = oRSA.Encrypt(lsData,False)
        write.Write(lsAOutput, 0, lsAOutput.Length)
        write.Flush()
    End If
Loop

read.Close ()
write.Close()

分段解密处理

\'获取key
Dim oRSA As New System.Security.Cryptography.RSACryptoServiceProvider()
Dim sr As New IO.StreamReader("d:\\test\\PrivateKey.xml")
Dim PrivateKey = sr.ReadToEnd
sr.Close()
oRSA.FromXmlString(PrivateKey)

\'读取和写入文件文件
Dim read As new IO.FileStream("d:\\test\\test加密.txt", IO.FileMode.Open)
Dim data(oRSA.KeySize/8-1) As Byte
Dim write As new IO.FileStream("d:\\test\\test解密.txt", IO.FileMode.Create)

Do While read.Read(data, 0, data.Length) > 0
    Dim AInput As Byte() = oRSA.Decrypt(data ,False)
    write.Write(AInput, 0, AInput.Length)
    write.Flush()
Loop
read.Close ()
write.Close()