AesCryptoServiceProvider.CreateDecryptor 方法

定義

命名空間:

System.Security.Cryptography

組件:

System.Security.Cryptography.dll

建立對稱的 AES 解密子物件。

多載

CreateDecryptor()	建立對稱的 AES 解密子物件，使用目前的金鑰和初始化向量 (IV)。
CreateDecryptor(Byte[], Byte[])	建立對稱的 AES 解密子物件，使用指定的金鑰和初始化向量 (IV)。

CreateDecryptor()

來源:

AesCryptoServiceProvider.cs

建立對稱的 AES 解密子物件，使用目前的金鑰和初始化向量 (IV)。

public:
 override System::Security::Cryptography::ICryptoTransform ^ CreateDecryptor();

public override System.Security.Cryptography.ICryptoTransform CreateDecryptor ();

override this.CreateDecryptor : unit -> System.Security.Cryptography.ICryptoTransform

Public Overrides Function CreateDecryptor () As ICryptoTransform

傳回

ICryptoTransform

對稱 AES 解密子物件。

例外狀況

CryptographicException

目前的金鑰無效或遺失。

CreateDecryptor(Byte[], Byte[])

來源:

AesCryptoServiceProvider.cs

建立對稱的 AES 解密子物件，使用指定的金鑰和初始化向量 (IV)。

public:
 override System::Security::Cryptography::ICryptoTransform ^ CreateDecryptor(cli::array <System::Byte> ^ rgbKey, cli::array <System::Byte> ^ rgbIV);

public override System.Security.Cryptography.ICryptoTransform CreateDecryptor (byte[] rgbKey, byte[]? rgbIV);

override this.CreateDecryptor : byte[] * byte[] -> System.Security.Cryptography.ICryptoTransform

Public Overrides Function CreateDecryptor (rgbKey As Byte(), rgbIV As Byte()) As ICryptoTransform

參數

rgbKey

Byte[]

對稱演算法所用的祕密金鑰。

rgbIV

Byte[]

對稱演算法所用的初始化向量。

傳回

ICryptoTransform

對稱 AES 解密子物件。

例外狀況

ArgumentNullException

key 或 iv 為 null。

ArgumentException

key 無效。

範例

下列範例示範如何使用 AesCryptoServiceProvider.CreateDecryptor 方法來解密加密的訊息。 此程式代碼範例是針對 類別提供的較大範例的 AesCryptoServiceProvider 一部分。

static string DecryptStringFromBytes_Aes(byte[] cipherText, byte[] Key, byte[] IV)
{
    // Check arguments.
    if (cipherText == null || cipherText.Length <= 0)
        throw new ArgumentNullException("cipherText");
    if (Key == null || Key.Length <= 0)
        throw new ArgumentNullException("Key");
    if (IV == null || IV.Length <= 0)
        throw new ArgumentNullException("IV");

    // Declare the string used to hold
    // the decrypted text.
    string plaintext = null;

    // Create an AesCryptoServiceProvider object
    // with the specified key and IV.
    using (AesCryptoServiceProvider aesAlg = new AesCryptoServiceProvider())
    {
        aesAlg.Key = Key;
        aesAlg.IV = IV;

        // Create a decryptor to perform the stream transform.
        ICryptoTransform decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV);

        // Create the streams used for decryption.
        using (MemoryStream msDecrypt = new MemoryStream(cipherText))
        {
            using (CryptoStream csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read))
            {
                using (StreamReader srDecrypt = new StreamReader(csDecrypt))
                {

                    // Read the decrypted bytes from the decrypting stream
                    // and place them in a string.
                    plaintext = srDecrypt.ReadToEnd();
                }
            }
        }
    }

    return plaintext;
}

    Shared Function DecryptStringFromBytes_Aes(ByVal cipherText() As Byte,ByVal Key() As Byte, ByVal IV() As Byte) As String
        ' Check arguments.
        If cipherText Is Nothing OrElse cipherText.Length <= 0 Then
            Throw New ArgumentNullException("cipherText")
        End If
        If Key Is Nothing OrElse Key.Length <= 0 Then
            Throw New ArgumentNullException("Key")
        End If
        If IV Is Nothing OrElse IV.Length <= 0 Then
            Throw New ArgumentNullException("IV")
        End If
        ' Declare the string used to hold
        ' the decrypted text.
        Dim plaintext As String = Nothing

        ' Create an AesCryptoServiceProvider object
        ' with the specified key and IV.
        Using aesAlg As New AesCryptoServiceProvider()

            aesAlg.Key = Key
            aesAlg.IV = IV

            ' Create a decryptor to perform the stream transform.
            Dim decryptor As ICryptoTransform = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV)

            ' Create the streams used for decryption.
            Using msDecrypt As New MemoryStream(cipherText)

                Using csDecrypt As New CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)

                    Using srDecrypt As New StreamReader(csDecrypt)

                        ' Read the decrypted bytes from the decrypting stream
                        ' and place them in a string.
                        plaintext = srDecrypt.ReadToEnd()
                    End Using
                End Using
            End Using
        End Using
        Return plaintext

    End Function 'DecryptStringFromBytes_Aes 
End Class

let decryptStringFromBytes_Aes (cipherText : byte[], key : byte[], iv : byte[]) : string =

    // Check arguments.
    if (isNull cipherText || cipherText.Length <= 0) then nullArg "cipherText"
    if (isNull key || key.Length <= 0) then nullArg "key"
    if (isNull iv || iv.Length <= 0) then nullArg "iv"

    // Create an AesCryptoServiceProvider object
    // with the specified key and IV.
    use aesAlg = new AesCryptoServiceProvider()
    aesAlg.Key <- key
    aesAlg.IV <- iv

    // Create a decryptor to perform the stream transform.
    let decryptor = aesAlg.CreateDecryptor(aesAlg.Key, aesAlg.IV)

    // Create the streams used for decryption.
    use msDecrypt = new MemoryStream(cipherText)
    use csDecrypt = new CryptoStream(msDecrypt, decryptor, CryptoStreamMode.Read)
    use srDecrypt = new StreamReader(csDecrypt)

    // Read the decrypted bytes from the decrypting stream
    // and return the resulting string.
    srDecrypt.ReadToEnd()