解码 OAEP 填充时出错

我的问题已经解决了一半..请帮助..

我已使用数字签名的公钥成功加密了文本，但在解密时出现错误。

解码 OAEP 填充时出错。

我的代码如下。

#region Test Encryption
public void a()
{
    using (var rsa = new RSACryptoServiceProvider())
    {
        // This String consists only Public Key Information 
        String publicKeyOnly = rsa.ToXmlString(false);

        // This String consists both Private/Public Key information 
        String publicPrivate = rsa.ToXmlString(true);
    }
}

//encrypt 
public byte[] b(String publicKeyOnly)
{
    byte[] encryptedData;

    using (var rsaPublicOnly = new RSACryptoServiceProvider())
    {
        rsaPublicOnly.FromXmlString(publicKeyOnly);
        encryptedData = rsaPublicOnly.Encrypt(
        Encoding.UTF8.GetBytes("This String is to be Secured."), true);
    }

    return encryptedData;
}

//Decrypt 
public String c(byte[] encryptedData)
{
    String decryptedPassword;

    using (var rsaPublicPrivate = new RSACryptoServiceProvider())
    {
        RSACryptoServiceProvider.UseMachineKeyStore = true;

        // Providing Private key information to RSA Object 
        rsaPublicPrivate.FromXmlString(_PrivateKeyXML);

        // Decrypting the encrypted data by using RSA object "rsaPublicPrivate" 
        decryptedPassword = rsaPublicPrivate.Decrypt(encryptedData, true).ToString();
    }

    return decryptedPassword;
}
#endregion