RSAOAEPKeyExchangeFormatter Class
Updated: March 2011
Creates Optimal Asymmetric Encryption Padding (OAEP) key exchange data using RSA.
System.Security.Cryptography.AsymmetricKeyExchangeFormatter
System.Security.Cryptography.RSAOAEPKeyExchangeFormatter
Assembly: mscorlib (in mscorlib.dll)
The RSAOAEPKeyExchangeFormatter type exposes the following members.
| Name | Description | |
|---|---|---|
![]() | RSAOAEPKeyExchangeFormatter | Initializes a new instance of the RSAOAEPKeyExchangeFormatter class. |
![]() | RSAOAEPKeyExchangeFormatter(AsymmetricAlgorithm) | Initializes a new instance of the RSAOAEPKeyExchangeFormatter class with the specified key. |
| Name | Description | |
|---|---|---|
![]() | Parameter | Infrastructure. Gets or sets the parameter used to create padding in the key exchange creation process. |
![]() | Parameters | Infrastructure. Gets the parameters for the Optimal Asymmetric Encryption Padding (OAEP) key exchange. (Overrides AsymmetricKeyExchangeFormatter.Parameters.) |
![]() | Rng | Gets or sets the random number generator algorithm to use in the creation of the key exchange. |
| Name | Description | |
|---|---|---|
![]() | CreateKeyExchange(Byte()) | Creates the encrypted key exchange data from the specified input data. (Overrides AsymmetricKeyExchangeFormatter.CreateKeyExchange(Byte()).) |
![]() | CreateKeyExchange(Byte(), Type) | Creates the encrypted key exchange data from the specified input data. (Overrides AsymmetricKeyExchangeFormatter.CreateKeyExchange(Byte(), Type).) |
![]() | Equals(Object) | Determines whether the specified Object is equal to the current Object. (Inherited from Object.) |
![]() | Finalize | Allows an object to try to free resources and perform other cleanup operations before it is reclaimed by garbage collection. (Inherited from Object.) |
![]() | GetHashCode | Serves as a hash function for a particular type. (Inherited from Object.) |
![]() | GetType | Gets the Type of the current instance. (Inherited from Object.) |
![]() | MemberwiseClone | Creates a shallow copy of the current Object. (Inherited from Object.) |
![]() | SetKey | Sets the public key to use for encrypting the key exchange data. (Overrides AsymmetricKeyExchangeFormatter.SetKey(AsymmetricAlgorithm).) |
![]() | ToString | Returns a string that represents the current object. (Inherited from Object.) |
Key exchange allows a sender to create secret information, for example, random data that can be used as a key in a symmetric encryption algorithm, and use encryption to send it to the intended recipient.
Use RSAOAEPKeyExchangeDeformatter to receive the key exchange and extract the secret information from it.
Caution |
|---|
It is highly recommended that you not attempt to create your own key exchange method from the basic functionality provided, because many details of the operation must be performed carefully in order for the key exchange to be successful. |
The following example shows how to use the RSAOAEPKeyExchangeFormatter class to create an exchange key for a message recipient.
Imports System Imports System.IO Imports System.Security.Cryptography Imports System.Text Class Alice Public Shared Sub Main(ByVal args() As String) Using bob As New Bob() Using rsaKey As New RSACryptoServiceProvider() ' Get Bob's public key rsaKey.ImportCspBlob(bob.key) Dim encryptedSessionKey As Byte() = Nothing Dim encryptedMessage As Byte() = Nothing Dim iv As Byte() = Nothing Send(rsaKey, "Secret message", iv, encryptedSessionKey, encryptedMessage) bob.Receive(iv, encryptedSessionKey, encryptedMessage) End Using End Using End Sub 'Main Private Shared Sub Send(ByVal key As RSA, ByVal secretMessage As String, ByRef iv() As Byte, ByRef encryptedSessionKey() As Byte, ByRef encryptedMessage() As Byte) Using aes = New AesCryptoServiceProvider() iv = aes.IV ' Encrypt the session key Dim keyFormatter As New RSAOAEPKeyExchangeFormatter(key) encryptedSessionKey = keyFormatter.CreateKeyExchange(aes.Key, GetType(Aes)) ' Encrypt the message Using ciphertext As New MemoryStream() Using cs As New CryptoStream(ciphertext, aes.CreateEncryptor(), CryptoStreamMode.Write) Dim plaintextMessage As Byte() = Encoding.UTF8.GetBytes(secretMessage) cs.Write(plaintextMessage, 0, plaintextMessage.Length) cs.Close() encryptedMessage = ciphertext.ToArray() End Using End Using End Using End Sub 'Send End Class 'Alice Public Class Bob Implements IDisposable Public key() As Byte Private rsaKey As New RSACryptoServiceProvider() Public Sub New() key = rsaKey.ExportCspBlob(False) End Sub 'New Public Sub Receive(ByVal iv() As Byte, ByVal encryptedSessionKey() As Byte, ByVal encryptedMessage() As Byte) Using aes = New AesCryptoServiceProvider() aes.IV = iv ' Decrypt the session key Dim keyDeformatter As New RSAOAEPKeyExchangeDeformatter(rsaKey) aes.Key = keyDeformatter.DecryptKeyExchange(encryptedSessionKey) ' Decrypt the message Using plaintext As New MemoryStream() Using cs As New CryptoStream(plaintext, aes.CreateDecryptor(), CryptoStreamMode.Write) cs.Write(encryptedMessage, 0, encryptedMessage.Length) cs.Close() Dim message As String = Encoding.UTF8.GetString(plaintext.ToArray()) Console.WriteLine(message) End Using End Using End Using End Sub 'Receive Public Overloads Sub Dispose() Implements IDisposable.Dispose rsaKey.Dispose() End Sub 'Dispose End Class 'Bob
Windows 7, Windows Vista SP1 or later, Windows XP SP3, Windows XP SP2 x64 Edition, Windows Server 2008 (Server Core not supported), Windows Server 2008 R2 (Server Core supported with SP1 or later), Windows Server 2003 SP2
The .NET Framework does not support all versions of every platform. For a list of the supported versions, see .NET Framework System Requirements.



Caution