AesManaged.CreateDecryptor メソッド

定義

名前空間:

System.Security.Cryptography

アセンブリ:

System.Security.Cryptography.Algorithms.dll

アセンブリ:

System.Security.Cryptography.dll

アセンブリ:

System.Core.dll

アセンブリ:

netstandard.dll

対称復号化オブジェクトを作成します。

オーバーロード

CreateDecryptor()	現在のキーおよび IV を使用して、対称復号化オブジェクトを作成します。
CreateDecryptor(Byte[], Byte[])	指定したキーおよび IV を使用して、対称復号化オブジェクトを作成します。

CreateDecryptor()

現在のキーおよび IV を使用して、対称復号化オブジェクトを作成します。

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

戻り値

ICryptoTransform

対称復号化オブジェクト。

CreateDecryptor(Byte[], Byte[])

指定したキーおよび IV を使用して、対称復号化オブジェクトを作成します。

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

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

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

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

public override System.Security.Cryptography.ICryptoTransform CreateDecryptor (byte[] key, byte[] iv);

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

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

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

Public Overrides Function CreateDecryptor (key As Byte(), iv As Byte()) As ICryptoTransform

パラメーター

rgbKeykey

Byte[]

対称アルゴリズムに使用する共有キー。

rgbIViv

Byte[]

対称アルゴリズムに使用する初期化ベクター。

戻り値

ICryptoTransform

対称復号化オブジェクト。

例外

ArgumentNullException

key または iv が null です。

ArgumentException

key が無効です。

例

次の例は、このメソッドを使用 AesManaged.CreateDecryptor して暗号化されたメッセージの暗号化を解除する方法を示しています。 このコード例は、AesManaged クラスのために提供されている大規模な例の一部です。

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 AesManaged object
    // with the specified key and IV.
    using (AesManaged aesAlg = new AesManaged())
    {
        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 AesManaged object
        ' with the specified key and IV.
        Using aesAlg As New AesManaged
            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 AesManaged object
    // with the specified key and IV.
    use aesAlg = new AesManaged()
    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()