TripleDES 類別
定義
重要
部分資訊涉及發行前產品，在發行之前可能會有大幅修改。 Microsoft 對此處提供的資訊，不做任何明確或隱含的瑕疵擔保。
代表三重資料加密標準演算法的基底類別，所有 TripleDES 實作都必須從此衍生出來。
public ref class TripleDES abstract : System::Security::Cryptography::SymmetricAlgorithmpublic abstract class TripleDES : System.Security.Cryptography.SymmetricAlgorithm[System.Runtime.Versioning.UnsupportedOSPlatform("browser")]
public abstract class TripleDES : System.Security.Cryptography.SymmetricAlgorithm[System.Runtime.InteropServices.ComVisible(true)]
public abstract class TripleDES : System.Security.Cryptography.SymmetricAlgorithmtype TripleDES = class
inherit SymmetricAlgorithm[<System.Runtime.Versioning.UnsupportedOSPlatform("browser")>]
type TripleDES = class
inherit SymmetricAlgorithm[<System.Runtime.InteropServices.ComVisible(true)>]
type TripleDES = class
inherit SymmetricAlgorithmPublic MustInherit Class TripleDES
Inherits SymmetricAlgorithm- 繼承
- 衍生
- 屬性
範例
以下程式碼範例展示了如何建立並使用 TripleDES 物件來加密和解密檔案中的資料。
using System;
using System.IO;
using System.Security.Cryptography;
using System.Text;
class TripleDESSample
{
static void Main()
{
try
{
byte[] key;
byte[] iv;
// Create a new TripleDES object to generate a random key
// and initialization vector (IV).
using (TripleDES tripleDes = TripleDES.Create())
{
key = tripleDes.Key;
iv = tripleDes.IV;
}
// Create a string to encrypt.
string original = "Here is some data to encrypt.";
// The name/path of the file to write.
string filename = "CText.enc";
// Encrypt the string to a file.
EncryptTextToFile(original, filename, key, iv);
// Decrypt the file back to a string.
string decrypted = DecryptTextFromFile(filename, key, iv);
// Display the decrypted string to the console.
Console.WriteLine(decrypted);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
public static void EncryptTextToFile(string text, string path, byte[] key, byte[] iv)
{
try
{
// Create or open the specified file.
using (FileStream fStream = File.Open(path, FileMode.Create))
// Create a new TripleDES object.
using (TripleDES tripleDes = TripleDES.Create())
// Create a TripleDES encryptor from the key and IV
using (ICryptoTransform encryptor = tripleDes.CreateEncryptor(key, iv))
// Create a CryptoStream using the FileStream and encryptor
using (var cStream = new CryptoStream(fStream, encryptor, CryptoStreamMode.Write))
{
// Convert the provided string to a byte array.
byte[] toEncrypt = Encoding.UTF8.GetBytes(text);
// Write the byte array to the crypto stream.
cStream.Write(toEncrypt, 0, toEncrypt.Length);
}
}
catch (CryptographicException e)
{
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
throw;
}
}
public static string DecryptTextFromFile(string path, byte[] key, byte[] iv)
{
try
{
// Open the specified file
using (FileStream fStream = File.OpenRead(path))
// Create a new TripleDES object.
using (TripleDES tripleDes = TripleDES.Create())
// Create a TripleDES decryptor from the key and IV
using (ICryptoTransform decryptor = tripleDes.CreateDecryptor(key, iv))
// Create a CryptoStream using the FileStream and decryptor
using (var cStream = new CryptoStream(fStream, decryptor, CryptoStreamMode.Read))
// Create a StreamReader to turn the bytes back into text
using (StreamReader reader = new StreamReader(cStream, Encoding.UTF8))
{
// Read back all of the text from the StreamReader, which receives
// the decrypted bytes from the CryptoStream, which receives the
// encrypted bytes from the FileStream.
return reader.ReadToEnd();
}
}
catch (CryptographicException e)
{
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
throw;
}
}
}
Imports System.IO
Imports System.Security.Cryptography
Imports System.Text
Module TripleDESSample
Sub Main()
Try
Dim key As Byte()
Dim iv As Byte()
' Create a new TripleDES object to generate a key
' and initialization vector (IV).
Using tripleDes As TripleDES = TripleDES.Create
key = tripleDes.Key
iv = tripleDes.IV
End Using
' Create a string to encrypt.
Dim original As String = "Here is some data to encrypt."
' The name/path of the file to write.
Dim filename As String = "CText.enc"
' Encrypt the string to a file.
EncryptTextToFile(original, filename, key, iv)
' Decrypt the file back to a string.
Dim decrypted As String = DecryptTextFromFile(filename, key, iv)
' Display the decrypted string to the console.
Console.WriteLine(decrypted)
Catch e As Exception
Console.WriteLine(e.Message)
End Try
End Sub
Sub EncryptTextToFile(text As String, path As String, key As Byte(), iv As Byte())
Try
' Create or open the specified file.
' Create a new TripleDES object,
' Create a TripleDES encryptor from the key and IV,
' Create a CryptoStream using the MemoryStream And encryptor
Using fStream As FileStream = File.Open(path, FileMode.Create),
tripleDes As TripleDES = TripleDES.Create,
encryptor As ICryptoTransform = tripleDes.CreateEncryptor(key, iv),
cStream = New CryptoStream(fStream, encryptor, CryptoStreamMode.Write)
' Convert the passed string to a byte array.
Dim toEncrypt As Byte() = Encoding.UTF8.GetBytes(text)
' Write the byte array to the crypto stream.
cStream.Write(toEncrypt, 0, toEncrypt.Length)
End Using
Catch e As CryptographicException
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
Throw
End Try
End Sub
Function DecryptTextFromFile(path As String, key As Byte(), iv As Byte()) As String
Try
' Open the specified file
' Create a new TripleDES object.
' Create a TripleDES decryptor from the key and IV
' Create a CryptoStream using the MemoryStream and decryptor
' Create a StreamReader to turn the bytes back into text
Using mStream As FileStream = File.OpenRead(path),
tripleDes As TripleDES = TripleDES.Create,
decryptor As ICryptoTransform = tripleDes.CreateDecryptor(key, iv),
cStream = New CryptoStream(mStream, decryptor, CryptoStreamMode.Read),
reader = New StreamReader(cStream, Encoding.UTF8)
' Read back all of the text from the StreamReader, which receives
' the decrypted bytes from the CryptoStream, which receives the
' encrypted bytes from the FileStream.
Return reader.ReadToEnd()
End Using
Catch e As CryptographicException
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
Return Nothing
End Try
End Function
End Module
以下程式碼範例展示如何建立並使用 TripleDES 物件來加密與解密記憶體中的資料。
using System;
using System.Security.Cryptography;
using System.Text;
using System.IO;
class TripleDESSample2
{
static void Main()
{
try
{
byte[] key;
byte[] iv;
// Create a new TripleDES object to generate a random key
// and initialization vector (IV).
using (TripleDES tripleDes = TripleDES.Create())
{
key = tripleDes.Key;
iv = tripleDes.IV;
}
// Create a string to encrypt.
string original = "Here is some data to encrypt.";
// Encrypt the string to an in-memory buffer.
byte[] encrypted = EncryptTextToMemory(original, key, iv);
// Decrypt the buffer back to a string.
string decrypted = DecryptTextFromMemory(encrypted, key, iv);
// Display the decrypted string to the console.
Console.WriteLine(decrypted);
}
catch (Exception e)
{
Console.WriteLine(e.Message);
}
}
public static byte[] EncryptTextToMemory(string text, byte[] key, byte[] iv)
{
try
{
// Create a MemoryStream.
using (MemoryStream mStream = new MemoryStream())
{
// Create a new TripleDES object.
using (TripleDES tripleDes = TripleDES.Create())
// Create a TripleDES encryptor from the key and IV
using (ICryptoTransform encryptor = tripleDes.CreateEncryptor(key, iv))
// Create a CryptoStream using the MemoryStream and encryptor
using (var cStream = new CryptoStream(mStream, encryptor, CryptoStreamMode.Write))
{
// Convert the provided string to a byte array.
byte[] toEncrypt = Encoding.UTF8.GetBytes(text);
// Write the byte array to the crypto stream and flush it.
cStream.Write(toEncrypt, 0, toEncrypt.Length);
// Ending the using statement for the CryptoStream completes the encryption.
}
// Get an array of bytes from the MemoryStream that holds the encrypted data.
byte[] ret = mStream.ToArray();
// Return the encrypted buffer.
return ret;
}
}
catch (CryptographicException e)
{
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
throw;
}
}
public static string DecryptTextFromMemory(byte[] encrypted, byte[] key, byte[] iv)
{
try
{
// Create a buffer to hold the decrypted data.
// TripleDES-encrypted data will always be slightly bigger than the decrypted data.
byte[] decrypted = new byte[encrypted.Length];
int offset = 0;
// Create a new MemoryStream using the provided array of encrypted data.
using (MemoryStream mStream = new MemoryStream(encrypted))
{
// Create a new TripleDES object.
using (TripleDES tripleDes = TripleDES.Create())
// Create a TripleDES decryptor from the key and IV
using (ICryptoTransform decryptor = tripleDes.CreateDecryptor(key, iv))
// Create a CryptoStream using the MemoryStream and decryptor
using (var cStream = new CryptoStream(mStream, decryptor, CryptoStreamMode.Read))
{
// Keep reading from the CryptoStream until it finishes (returns 0).
int read = 1;
while (read > 0)
{
read = cStream.Read(decrypted, offset, decrypted.Length - offset);
offset += read;
}
}
}
// Convert the buffer into a string and return it.
return Encoding.UTF8.GetString(decrypted, 0, offset);
}
catch (CryptographicException e)
{
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message);
throw;
}
}
}
Imports System.Security.Cryptography
Imports System.Text
Imports System.IO
Module MemorySample
Sub Main()
Try
Dim key As Byte()
Dim iv As Byte()
' Create a new TripleDES object to generate a key
' and initialization vector (IV).
Using tripleDes As TripleDES = TripleDES.Create
key = tripleDes.Key
iv = tripleDes.IV
End Using
' Create a string to encrypt.
Dim original As String = "Here is some data to encrypt."
' Encrypt the string to an in-memory buffer.
Dim encrypted As Byte() = EncryptTextToMemory(original, key, iv)
' Decrypt the buffer back to a string.
Dim decrypted As String = DecryptTextFromMemory(encrypted, key, iv)
' Display the decrypted string to the console.
Console.WriteLine(decrypted)
Catch e As Exception
Console.WriteLine(e.Message)
End Try
End Sub
Function EncryptTextToMemory(text As String, key As Byte(), iv As Byte()) As Byte()
Try
' Create a MemoryStream.
Using mStream As New MemoryStream
' Create a new TripleDES object,
' Create a TripleDES encryptor from the key and IV,
' Create a CryptoStream using the MemoryStream And encryptor
Using tripleDes As TripleDES = TripleDES.Create,
encryptor As ICryptoTransform = tripleDes.CreateEncryptor(key, iv),
cStream = New CryptoStream(mStream, encryptor, CryptoStreamMode.Write)
' Convert the passed string to a byte array.
Dim toEncrypt As Byte() = Encoding.UTF8.GetBytes(text)
' Write the byte array to the crypto stream and flush it.
cStream.Write(toEncrypt, 0, toEncrypt.Length)
' Ending the using block for the CryptoStream completes the encryption.
End Using
' Get an array of bytes from the MemoryStream that holds the encrypted data.
Dim ret As Byte() = mStream.ToArray()
' Return the encrypted buffer.
Return ret
End Using
Catch e As CryptographicException
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
Throw
End Try
End Function
Function DecryptTextFromMemory(encrypted As Byte(), key As Byte(), iv As Byte()) As String
Try
' Create a buffer to hold the decrypted data.
' TripleDES-encrypted data will always be slightly bigger than the decrypted data.
Dim decrypted(encrypted.Length - 1) As Byte
Dim offset As Integer = 0
' Create a new MemoryStream using the provided array of encrypted data.
' Create a new TripleDES object.
' Create a TripleDES decryptor from the key and IV
' Create a CryptoStream using the MemoryStream and decryptor
Using mStream As New MemoryStream(encrypted),
tripleDes As TripleDES = TripleDES.Create,
decryptor As ICryptoTransform = tripleDes.CreateDecryptor(key, iv),
cStream = New CryptoStream(mStream, decryptor, CryptoStreamMode.Read)
' Keep reading from the CryptoStream until it finishes (returns 0).
Dim read As Integer = 1
While (read > 0)
read = cStream.Read(decrypted, offset, decrypted.Length - offset)
offset += read
End While
End Using
' Convert the buffer into a string and return it.
Return New ASCIIEncoding().GetString(decrypted, 0, offset)
Catch e As CryptographicException
Console.WriteLine("A Cryptographic error occurred: {0}", e.Message)
Return Nothing
End Try
End Function
End Module
備註
TripleDES 使用演算法的三次連續迭代 DES 。 它可以使用兩個或三個 56 位元金鑰。
Note
一種更新的對稱加密演算法——先進加密標準（AES）——也可用。 考慮使用 該 Aes 類別及其衍生類別，而非類別本身 TripleDES 。 僅用於 TripleDES 與舊有應用程式及資料相容性。
此演算法支援從 128 位元到 192 位元的金鑰長度，且以 64 位元為單位遞增。
建構函式
| 名稱 | Description |
|---|---|
| TripleDES() |
初始化 TripleDES 類別的新執行個體。 |
欄位
| 名稱 | Description |
|---|---|
| BlockSizeValue |
代表密碼運算的區塊大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| FeedbackSizeValue |
代表密碼運算的反饋大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| IVValue |
代表對稱演算法的初始化向量（IV）。 (繼承來源 SymmetricAlgorithm) |
| KeySizeValue |
代表對稱演算法所使用的秘密金鑰的大小（以位元為單位）。 (繼承來源 SymmetricAlgorithm) |
| KeyValue |
代表對稱演算法的祕密金鑰。 (繼承來源 SymmetricAlgorithm) |
| LegalBlockSizesValue |
指定對稱演算法所支援的區塊大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| LegalKeySizesValue |
指定對稱演算法所支援的金鑰大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| ModeValue |
代表對稱演算法中使用的密碼模式。 (繼承來源 SymmetricAlgorithm) |
| PaddingValue |
代表對稱演算法中使用的填充模式。 (繼承來源 SymmetricAlgorithm) |
屬性
| 名稱 | Description |
|---|---|
| BlockSize |
取得或設定密碼運算的區塊大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| FeedbackSize |
取得或設定密碼反饋（CFB）與輸出反饋（OFB）密碼模式的反饋大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| IV |
取得或設定對稱演算法的初始化向量（IV）。 (繼承來源 SymmetricAlgorithm) |
| Key |
取得或設定演算法的 TripleDES 秘密金鑰。 |
| KeySize |
取得或設定對稱演算法所使用的秘密金鑰的大小（以位元為單位）。 (繼承來源 SymmetricAlgorithm) |
| LegalBlockSizes |
取得對稱演算法所支援的區塊大小（位元）。 |
| LegalBlockSizes |
取得對稱演算法所支援的區塊大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| LegalKeySizes |
取得對稱演算法所支援的金鑰大小（位元）。 |
| LegalKeySizes |
取得對稱演算法所支援的金鑰大小（位元）。 (繼承來源 SymmetricAlgorithm) |
| Mode |
取得或設定對稱演算法的運作模式。 (繼承來源 SymmetricAlgorithm) |
| Padding |
取得或設定對稱演算法中使用的填充模式。 (繼承來源 SymmetricAlgorithm) |
方法
明確介面實作
| 名稱 | Description |
|---|---|
| IDisposable.Dispose() |
此 API 支援此產品基礎結構，但無法直接用於程式碼之中。 釋放 未管理的資源， SymmetricAlgorithm 並可選擇性地釋放受管理資源。 (繼承來源 SymmetricAlgorithm) |
