public async Task KeyVault_CapacityLimitOfCachingKeyResolver()
{
var mockedResolver = new Mock<IKeyResolver>();
var ct = default(CancellationToken);
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.Returns(Task.FromResult<IKey>(new RsaKey(KeyId)));
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId2, ct))
.Returns(Task.FromResult<IKey>(new RsaKey(KeyId2)));
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId3, ct))
.Returns(Task.FromResult<IKey>(new RsaKey(KeyId3)));
using (var resolver = new CachingKeyResolver(2, mockedResolver.Object))
{
// Three items are added to the cache and because the size of the cache is 2
// after the third key is added the least recently used (LRU) key (first key) is evicted
await resolver.ResolveKeyAsync(KeyId, ct);
await resolver.ResolveKeyAsync(KeyId2, ct);
await resolver.ResolveKeyAsync(KeyId3, ct);
// First Key is evicted; so it is going to be added to the cache again when its key is resolved
// and second key is evicted to open space for first key as it is the LRU key
await resolver.ResolveKeyAsync(KeyId2, ct);
await resolver.ResolveKeyAsync(KeyId3, ct);
await resolver.ResolveKeyAsync(KeyId, ct);
await resolver.ResolveKeyAsync(KeyId3, ct);
}
mockedResolver.Verify(r => r.ResolveKeyAsync(KeyId2, ct), Times.Once());
mockedResolver.Verify(r => r.ResolveKeyAsync(KeyId3, ct), Times.Once());
mockedResolver.Verify(r => r.ResolveKeyAsync(KeyId, ct), Times.Exactly(2));
}
static void Main(string[] args)
{
Console.WriteLine("Blob encryption with Key Vault integration demonstrating key rotation from Key 1 to Key 2");
Console.WriteLine();
// Create two secrets and obtain their IDs. This is normally a one-time setup step.
// Although it is possible to use keys (rather than secrets) stored in Key Vault, this prevents caching.
// Therefore it is recommended to use secrets along with a caching resolver (see below).
string keyID1 = EncryptionShared.KeyVaultUtility.SetUpKeyVaultSecret("KeyRotationSampleSecret1");
string keyID2 = EncryptionShared.KeyVaultUtility.SetUpKeyVaultSecret("KeyRotationSampleSecret2");
// Retrieve storage account information from connection string
// How to create a storage connection string - https://azure.microsoft.com/en-us/documentation/articles/storage-configure-connection-string/
CloudStorageAccount storageAccount = EncryptionShared.Utility.CreateStorageAccountFromConnectionString();
CloudBlobClient client = storageAccount.CreateCloudBlobClient();
CloudBlobContainer container = client.GetContainerReference(DemoContainer + Guid.NewGuid().ToString("N"));
// Construct a resolver capable of looking up keys and secrets stored in Key Vault.
KeyVaultKeyResolver cloudResolver = new KeyVaultKeyResolver(EncryptionShared.KeyVaultUtility.GetAccessToken);
// Set up a caching resolver so the secrets can be cached on the client. This is the recommended usage
// pattern since the throttling targets for Storage and Key Vault services are orders of magnitude
// different.
CachingKeyResolver cachingResolver = new CachingKeyResolver(2, cloudResolver);
// Create key instances corresponding to the key IDs. This will cache the secrets.
IKey cloudKey1 = cachingResolver.ResolveKeyAsync(keyID1, CancellationToken.None).GetAwaiter().GetResult();
IKey cloudKey2 = cachingResolver.ResolveKeyAsync(keyID2, CancellationToken.None).GetAwaiter().GetResult();
// We begin with cloudKey1, and a resolver capable of resolving and caching Key Vault secrets.
BlobEncryptionPolicy encryptionPolicy = new BlobEncryptionPolicy(cloudKey1, cachingResolver);
client.DefaultRequestOptions.EncryptionPolicy = encryptionPolicy;
client.DefaultRequestOptions.RequireEncryption = true;
try
{
container.Create();
int size = 5 * 1024 * 1024;
byte[] buffer1 = new byte[size];
byte[] buffer2 = new byte[size];
Random rand = new Random();
rand.NextBytes(buffer1);
rand.NextBytes(buffer2);
// Upload the first blob using the secret stored in Azure Key Vault.
CloudBlockBlob blob = container.GetBlockBlobReference("blockblob1");
Console.WriteLine("Uploading Blob 1 using Key 1.");
// Upload the encrypted contents to the first blob.
using (MemoryStream stream = new MemoryStream(buffer1))
{
blob.UploadFromStream(stream, size);
}
Console.WriteLine("Downloading and decrypting Blob 1.");
// Download and decrypt the encrypted contents from the first blob.
using (MemoryStream outputStream = new MemoryStream())
{
blob.DownloadToStream(outputStream);
}
// At this point we will rotate our keys so new encrypted content will use the
// second key. Note that the same resolver is used, as this resolver is capable
// of decrypting blobs encrypted using either key.
Console.WriteLine("Rotating the active encryption key to Key 2.");
client.DefaultRequestOptions.EncryptionPolicy = new BlobEncryptionPolicy(cloudKey2, cachingResolver);
// Upload the second blob using the key stored in Azure Key Vault.
CloudBlockBlob blob2 = container.GetBlockBlobReference("blockblob2");
Console.WriteLine("Uploading Blob 2 using Key 2.");
// Upload the encrypted contents to the second blob.
using (MemoryStream stream = new MemoryStream(buffer2))
{
blob2.UploadFromStream(stream, size);
}
Console.WriteLine("Downloading and decrypting Blob 2.");
// Download and decrypt the encrypted contents from the second blob.
using (MemoryStream outputStream = new MemoryStream())
{
blob2.DownloadToStream(outputStream);
}
// Here we download and re-upload the first blob. This has the effect of updating
// the blob to use the new key.
using (MemoryStream memoryStream = new MemoryStream())
{
Console.WriteLine("Downloading and decrypting Blob 1.");
blob.DownloadToStream(memoryStream);
memoryStream.Seek(0, SeekOrigin.Begin);
Console.WriteLine("Re-uploading Blob 1 using Key 2.");
blob.UploadFromStream(memoryStream);
}
// For the purposes of demonstration, we now override the encryption policy to only recognize key 2.
BlobEncryptionPolicy key2OnlyPolicy = new BlobEncryptionPolicy(cloudKey2, null);
BlobRequestOptions key2OnlyOptions = new BlobRequestOptions()
{
EncryptionPolicy = key2OnlyPolicy
};
Console.WriteLine("Downloading and decrypting Blob 1.");
// The first blob can still be decrypted because it is using the second key.
using (MemoryStream outputStream = new MemoryStream())
{
blob.DownloadToStream(outputStream, options: key2OnlyOptions);
}
Console.WriteLine("Press enter key to exit");
Console.ReadLine();
}
finally
{
container.DeleteIfExists();
}
}
public async Task KeyVault_CachingKeyResolverThrows()
{
var mockedResolver = new Mock<IKeyResolver>();
var ct = default(CancellationToken);
using (var resolver = new CachingKeyResolver(10, mockedResolver.Object))
{
// Throws
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.Throws(new EmptyException());
try
{
await resolver.ResolveKeyAsync(KeyId, ct);
}
catch (EmptyException) { }
// Throws async
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.ThrowsAsync(new FalseException("test"));
try
{
await resolver.ResolveKeyAsync(KeyId, ct);
}
catch (FalseException) { }
// Succeeds and caches
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.Returns(Task.FromResult<IKey>(new RsaKey(KeyId)));
await resolver.ResolveKeyAsync(KeyId, ct);
await resolver.ResolveKeyAsync(KeyId, ct);
resolver.Dispose();
}
mockedResolver.Verify(r => r.ResolveKeyAsync(KeyId, ct), Times.Exactly(3));
}
public async Task KeyVault_CachingKeyResolverDisposeCachedKey()
{
var mockedResolver = new Mock<IKeyResolver>();
var mockedKey = new Mock<IKey>();
var ct = default(CancellationToken);
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.Returns(Task.FromResult(mockedKey.Object));
using (var resolver = new CachingKeyResolver(2, mockedResolver.Object))
{
var cachedKey = await resolver.ResolveKeyAsync(KeyId, ct);
// key doesn't get disposed because dispose of key is disabled
cachedKey.Dispose();
mockedKey.Verify(k => k.Dispose(), Times.Never);
await resolver.ResolveKeyAsync(KeyId, ct);
}
// Dispose on key is only called when cache is disposing
mockedKey.Verify(k => k.Dispose(), Times.Exactly(1));
mockedResolver.Verify(r => r.ResolveKeyAsync(KeyId, ct), Times.Exactly(1));
}
public async Task KeyVault_CachingKeyResolverKeyIsDisposed()
{
var mockedResolver = new Mock<IKeyResolver>();
var mockedKey = new Mock<IKey>();
var ct = default(CancellationToken);
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.Returns(Task.FromResult(mockedKey.Object));
using (var resolver = new CachingKeyResolver(2, mockedResolver.Object))
{
await resolver.ResolveKeyAsync(KeyId, ct);
}
mockedKey.Verify(k => k.Dispose(), Times.Once);
}
public void KeyVault_CachingKeyResolverCapacityThreadSafety()
{
const int parallelThreads = 30;
var mockedResolver = new Mock<IKeyResolver>();
var ct = default(CancellationToken);
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId, ct))
.Returns(() => Task.FromResult<IKey>(new RsaKey(KeyId)));
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId2, ct))
.Returns(() => Task.FromResult<IKey>(new RsaKey(KeyId2)));
mockedResolver.Setup(r => r.ResolveKeyAsync(KeyId3, ct))
.Returns(() => Task.FromResult<IKey>(new RsaKey(KeyId3)));
using (var resolver = new CachingKeyResolver(2, mockedResolver.Object))
{
var tasks = new List<Task>();
for (var i = 0; i < parallelThreads; i += 3)
{
tasks.Add(Task.Run(() => resolver.ResolveKeyAsync(KeyId, ct), ct));
tasks.Add(Task.Run(() => resolver.ResolveKeyAsync(KeyId, ct), ct));
tasks.Add(Task.Run(() => resolver.ResolveKeyAsync(KeyId, ct), ct));
}
Task.WaitAll(tasks.ToArray());
}
}
static void Main(string[] args)
{
Console.WriteLine("Blob encryption with Key Vault integration");
Console.WriteLine();
// Get the key ID from App.config if it exists.
string keyID = CloudConfigurationManager.GetSetting("KeyID");
// If no key ID was specified, we will create a new secret in Key Vault.
// To create a new secret, this client needs full permission to Key Vault secrets.
// Once the secret is created, its ID can be added to App.config. Once this is done,
// this client only needs read access to secrets.
if (string.IsNullOrEmpty(keyID))
{
Console.WriteLine("No secret specified in App.config.");
Console.WriteLine("Please enter the name of a new secret to create in Key Vault.");
Console.WriteLine("WARNING: This will delete any existing secret with the same name.");
Console.Write("Name of the new secret to create [{0}]: ", DefaultSecretName);
string newSecretName = Console.ReadLine().Trim();
if (string.IsNullOrEmpty(newSecretName))
{
newSecretName = DefaultSecretName;
}
// Although it is possible to use keys (rather than secrets) stored in Key Vault, this prevents caching.
// Therefore it is recommended to use secrets along with a caching resolver (see below).
keyID = EncryptionShared.KeyVaultUtility.SetUpKeyVaultSecret(newSecretName);
Console.WriteLine();
Console.WriteLine("Created a secret with ID: {0}", keyID);
Console.WriteLine("Copy the secret ID to App.config to reuse.");
Console.WriteLine();
}
// Retrieve storage account information from connection string
// How to create a storage connection string - https://azure.microsoft.com/en-us/documentation/articles/storage-configure-connection-string/
CloudStorageAccount storageAccount = EncryptionShared.Utility.CreateStorageAccountFromConnectionString();
CloudBlobClient client = storageAccount.CreateCloudBlobClient();
CloudBlobContainer container = client.GetContainerReference(DemoContainer + Guid.NewGuid().ToString("N"));
// Construct a resolver capable of looking up keys and secrets stored in Key Vault.
KeyVaultKeyResolver cloudResolver = new KeyVaultKeyResolver(EncryptionShared.KeyVaultUtility.GetAccessToken);
// To demonstrate how multiple different types of key can be used, we also create a local key and resolver.
// This key is temporary and won't be persisted.
RsaKey rsaKey = new RsaKey("rsakey");
LocalResolver resolver = new LocalResolver();
resolver.Add(rsaKey);
// If there are multiple key sources like Azure Key Vault and local KMS, set up an aggregate resolver as follows.
// This helps users to define a plug-in model for all the different key providers they support.
AggregateKeyResolver aggregateResolver = new AggregateKeyResolver()
.Add(resolver)
.Add(cloudResolver);
// Set up a caching resolver so the secrets can be cached on the client. This is the recommended usage
// pattern since the throttling targets for Storage and Key Vault services are orders of magnitude
// different.
CachingKeyResolver cachingResolver = new CachingKeyResolver(2, aggregateResolver);
// Create a key instance corresponding to the key ID. This will cache the secret.
IKey cloudKey = cachingResolver.ResolveKeyAsync(keyID, CancellationToken.None).GetAwaiter().GetResult();
try
{
container.Create();
int size = 5 * 1024 * 1024;
byte[] buffer = new byte[size];
Random rand = new Random();
rand.NextBytes(buffer);
// The first blob will use the key stored in Azure Key Vault.
CloudBlockBlob blob = container.GetBlockBlobReference("blockblob1");
// Create the encryption policy using the secret stored in Azure Key Vault to be used for upload.
BlobEncryptionPolicy uploadPolicy = new BlobEncryptionPolicy(cloudKey, null);
// Set the encryption policy on the request options.
BlobRequestOptions uploadOptions = new BlobRequestOptions() { EncryptionPolicy = uploadPolicy };
Console.WriteLine("Uploading the 1st encrypted blob.");
// Upload the encrypted contents to the blob.
using (MemoryStream stream = new MemoryStream(buffer))
{
blob.UploadFromStream(stream, size, null, uploadOptions, null);
}
// Download the encrypted blob.
BlobEncryptionPolicy downloadPolicy = new BlobEncryptionPolicy(null, cachingResolver);
// Set the decryption policy on the request options.
BlobRequestOptions downloadOptions = new BlobRequestOptions() { EncryptionPolicy = downloadPolicy };
Console.WriteLine("Downloading the 1st encrypted blob.");
// Download and decrypt the encrypted contents from the blob.
using (MemoryStream outputStream = new MemoryStream())
{
blob.DownloadToStream(outputStream, null, downloadOptions, null);
}
// Upload second blob using the local key.
blob = container.GetBlockBlobReference("blockblob2");
// Create the encryption policy using the local key.
uploadPolicy = new BlobEncryptionPolicy(rsaKey, null);
// Set the encryption policy on the request options.
uploadOptions = new BlobRequestOptions() { EncryptionPolicy = uploadPolicy };
Console.WriteLine("Uploading the 2nd encrypted blob.");
// Upload the encrypted contents to the blob.
using (MemoryStream stream = new MemoryStream(buffer))
{
blob.UploadFromStream(stream, size, null, uploadOptions, null);
}
// Download the encrypted blob. The same policy and options created before can be used because the aggregate resolver contains both
// resolvers and will pick the right one based on the key ID stored in blob metadata on the service.
Console.WriteLine("Downloading the 2nd encrypted blob.");
// Download and decrypt the encrypted contents from the blob.
using (MemoryStream outputStream = new MemoryStream())
{
blob.DownloadToStream(outputStream, null, downloadOptions, null);
}
Console.WriteLine("Press enter key to exit");
Console.ReadLine();
}
finally
{
container.DeleteIfExists();
}
}