AesManaged.CreateDecryptor Method (Byte[], Byte[])

 

Creates a symmetric decryptor object using the specified key and initialization vector (IV).

Namespace:   System.Security.Cryptography
Assembly:  System.Core (in System.Core.dll)

public override ICryptoTransform CreateDecryptor(
	byte[] key,
	byte[] iv
)

Parameters

key
Type: System.Byte[]

The secret key to use for the symmetric algorithm.

iv
Type: System.Byte[]

The initialization vector to use for the symmetric algorithm.

Return Value

Type: System.Security.Cryptography.ICryptoTransform

A symmetric decryptor object.

Exception Condition
ArgumentNullException

key or iv is null.

ArgumentException

key is invalid.

The following example shows how to use the AesManaged.CreateDecryptor method to decrypt an encrypted message. This code example is part of a larger example provided for the AesManaged class.

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 decrytor 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;

}

.NET Framework
Available since 3.5
Silverlight
Available since 2.0
Windows Phone Silverlight
Available since 7.0
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