CryptoProvider.BlockSize 属性

定义

命名空间:

System.Security.RightsManagement

程序集:

WindowsBase.dll

获取密码块大小（以字节为单位）。

public:
 property int BlockSize { int get(); };

public int BlockSize { get; }

member this.BlockSize : int

Public ReadOnly Property BlockSize As Integer

属性值

Int32

密码块大小（以字节为单位）。 高级加密标准 (AES) 的默认块大小为 8。

示例

以下示例演示如何使用 BlockSize 属性将明文数据转换为加密文本数据。

WriteStatus("   Binding the author's UseLicense and");
WriteStatus("       obtaining the CryptoProvider.");
using (CryptoProvider cryptoProvider =
            authorsUseLicense.Bind(_secureEnv))
{
    WriteStatus("   Writing encrypted content.");
    using (Stream clearTextStream =
                File.OpenRead(contentFile) )
    {
        using (Stream cryptoTextStream =
                    File.OpenWrite(encryptedFile))
        {
            // Write the length of the source content file
            // as the first four bytes of the encrypted file.
            cryptoTextStream.Write(
                BitConverter.GetBytes(clearTextStream.Length),
                0, sizeof(Int32));

            // Allocate clearText buffer.
            byte[] clearTextBlock =
                new byte[cryptoProvider.BlockSize];

            // Encrypt clearText to cryptoText block by block.
            for(;;)
            {   // Read clearText block.
                int readCount = ReliableRead(
                                    clearTextStream,
                                    clearTextBlock, 0 ,
                                    cryptoProvider.BlockSize);
                // readCount of zero is end of data.
                if (readCount == 0)  break; // for

                // Encrypt clearText to cryptoText.
                byte[] cryptoTextBlock =
                    cryptoProvider.Encrypt(clearTextBlock);

                // Write cryptoText block.
                cryptoTextStream.Write(cryptoTextBlock, 0,
                                       cryptoTextBlock.Length);
            }
            WriteStatus("   Closing '" + encryptedFilename + "'.");
        }// end:using (Stream cryptoTextStream =
    }// end:using (Stream clearTextStream =
}// end:using (CryptoProvider cryptoProvider =
WriteStatus("   Done - Content encryption complete.");

WriteStatus("   Binding the author's UseLicense and")
WriteStatus("       obtaining the CryptoProvider.")
Using cryptoProvider As CryptoProvider = authorsUseLicense.Bind(_secureEnv)
    WriteStatus("   Writing encrypted content.")
    Using clearTextStream As Stream = File.OpenRead(contentFile)
        Using cryptoTextStream As Stream = File.OpenWrite(encryptedFile)
            ' Write the length of the source content file
            ' as the first four bytes of the encrypted file.
            Dim expression As Int32
            cryptoTextStream.Write(BitConverter.GetBytes(clearTextStream.Length), 0, Len(expression))

            ' Allocate clearText buffer.
            Dim clearTextBlock(cryptoProvider.BlockSize - 1) As Byte

            ' Encrypt clearText to cryptoText block by block.
            Do
                Dim readCount As Integer = ReliableRead(clearTextStream, clearTextBlock, 0, cryptoProvider.BlockSize)
                ' readCount of zero is end of data.
                If readCount = 0 Then ' for
                    Exit Do
                End If

                ' Encrypt clearText to cryptoText.
                Dim cryptoTextBlock() As Byte = cryptoProvider.Encrypt(clearTextBlock)

                ' Write cryptoText block.
                cryptoTextStream.Write(cryptoTextBlock, 0, cryptoTextBlock.Length)
            Loop
            WriteStatus("   Closing '" & encryptedFilename & "'.")
        End Using ' end:using (Stream cryptoTextStream =
    End Using ' end:using (Stream clearTextStream =
End Using ' end:using (CryptoProvider cryptoProvider =
WriteStatus("   Done - Content encryption complete.")

注解

clearText传递给 和 cipherTextDecrypt 的 Encrypt 和 缓冲区的长度必须为 n*BlockSize 个字节，其中“n”是大于或等于 1 的整数。

如果 CanMergeBlocks 为 false，则传递给 的 Encrypt 缓冲区的长度必须与传递给 Decrypt的缓冲区的长度相同。

如果 CanMergeBlocks 为 true，则传递给 的 Encrypt 缓冲区的长度可以不同于传递给 Decrypt 的缓冲区 (所有缓冲区大小仍必须始终是长度) 字节的 BlockSize 倍数。

为 BlockSize 1 的 表示密码是流密码; BlockSize 2 或更大的 表示块密码。