72 lines
3.2 KiB
C#
72 lines
3.2 KiB
C#
// Copyright (c) Microsoft Open Technologies, Inc. All rights reserved.
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// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
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using System;
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using System.Xml.Linq;
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using Microsoft.AspNet.Cryptography;
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using Microsoft.AspNet.DataProtection.XmlEncryption;
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namespace Microsoft.AspNet.DataProtection.AuthenticatedEncryption
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{
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internal sealed class CngGcmAuthenticatedEncryptorConfiguration : IAuthenticatedEncryptorConfiguration
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{
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internal static readonly XNamespace XmlNamespace = XNamespace.Get("http://www.asp.net/2014/dataProtection/cng");
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internal static readonly XName EncryptionElementName = XmlNamespace.GetName("encryption");
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internal static readonly XName GcmEncryptorElementName = XmlNamespace.GetName("gcmEncryptor");
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internal static readonly XName SecretElementName = XmlNamespace.GetName("secret");
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private readonly CngGcmAuthenticatedEncryptorConfigurationOptions _options;
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private readonly ISecret _secret;
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public CngGcmAuthenticatedEncryptorConfiguration(CngGcmAuthenticatedEncryptorConfigurationOptions options, ISecret secret)
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{
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_options = options;
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_secret = secret;
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}
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public IAuthenticatedEncryptor CreateEncryptorInstance()
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{
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return _options.CreateAuthenticatedEncryptor(_secret);
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}
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private XElement EncryptSecret(IXmlEncryptor encryptor)
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{
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// First, create the inner <secret> element.
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XElement secretElement;
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byte[] plaintextSecret = new byte[_secret.Length];
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try
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{
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_secret.WriteSecretIntoBuffer(new ArraySegment<byte>(plaintextSecret));
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secretElement = new XElement(SecretElementName, Convert.ToBase64String(plaintextSecret));
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}
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finally
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{
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Array.Clear(plaintextSecret, 0, plaintextSecret.Length);
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}
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// Then encrypt it and wrap it in another <secret> element.
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var encryptedSecretElement = encryptor.Encrypt(secretElement);
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CryptoUtil.Assert(!String.IsNullOrEmpty((string)encryptedSecretElement.Attribute("decryptor")),
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@"TODO: <secret> encryption was invalid.");
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return new XElement(SecretElementName, encryptedSecretElement);
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}
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public XElement ToXml([NotNull] IXmlEncryptor xmlEncryptor)
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{
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// <cbcEncryptor reader="{TYPE}">
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// <encryption algorithm="{STRING}" provider="{STRING}" keyLength="{INT}" />
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// <secret>...</secret>
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// </cbcEncryptor>
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return new XElement(GcmEncryptorElementName,
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new XAttribute("reader", typeof(CngGcmAuthenticatedEncryptorConfigurationXmlReader).AssemblyQualifiedName),
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new XElement(EncryptionElementName,
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new XAttribute("algorithm", _options.EncryptionAlgorithm),
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new XAttribute("provider", _options.EncryptionAlgorithmProvider ?? String.Empty),
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new XAttribute("keyLength", _options.EncryptionAlgorithmKeySize)),
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EncryptSecret(xmlEncryptor));
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}
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}
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}
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