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package com.unboundid.directory.sdk.examples;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.Arrays;
import java.util.LinkedHashMap;
import java.util.List;
import java.util.Map;
import javax.crypto.Cipher;
import javax.crypto.CipherInputStream;
import javax.crypto.CipherOutputStream;
import javax.crypto.SecretKey;
import javax.crypto.SecretKeyFactory;
import javax.crypto.spec.PBEKeySpec;
import javax.crypto.spec.SecretKeySpec;
import com.unboundid.directory.sdk.ds.api.CipherStreamProvider;
import com.unboundid.directory.sdk.ds.config.CipherStreamProviderConfig;
import com.unboundid.directory.sdk.ds.types.DirectoryServerContext;
import com.unboundid.ldap.sdk.LDAPException;
import com.unboundid.ldap.sdk.ResultCode;
import com.unboundid.util.StaticUtils;
import com.unboundid.util.args.ArgumentException;
import com.unboundid.util.args.ArgumentParser;
import com.unboundid.util.args.StringArgument;
/**
* This class provides a simple example of a cipher stream provider which will
* use a password (provided as an argument to this extension) to generate the
* key to use in order to perform encryption and decryption using a 128-bit AES
* cipher. It has a single configuration argument:
* <UL>
* <LI>key-password -- The password to use to generate the encryption
* key.</LI>
* </UL>
*/
public final class ExampleCipherStreamProvider
extends CipherStreamProvider
{
/**
* The name of the argument that will be used to specify the password to use
* when generating the encryption key.
*/
private static final String ARG_NAME_KEY_PASSWORD = "key-password";
// The characters that comprise the key password.
private volatile char[] keyPassword;
// The server context for the server in which this extension is running.
private DirectoryServerContext serverContext;
/**
* Creates a new instance of this cipher stream provider. All cipher stream
* provider implementations must include a default constructor, but any
* initialization should generally be done in the
* {@code initializeCipherStreamProvider} method.
*/
public ExampleCipherStreamProvider()
{
// No implementation required.
}
/**
* Retrieves a human-readable name for this extension.
*
* @return A human-readable name for this extension.
*/
@Override()
public String getExtensionName()
{
return "Example Cipher Stream Provider";
}
/**
* Retrieves a human-readable description for this extension. Each element
* of the array that is returned will be considered a separate paragraph in
* generated documentation.
*
* @return A human-readable description for this extension, or {@code null}
* or an empty array if no description should be available.
*/
@Override()
public String[] getExtensionDescription()
{
return new String[]
{
"This cipher stream provider uses a password provided in the " +
"key-password argument in order to generate the encryption key " +
"to use for encrypting and decrypting data using a 128-bit AES " +
"cipher."
};
}
/**
* Updates the provided argument parser to define any configuration arguments
* which may be used by this cipher stream provider. The argument parser may
* also be updated to define relationships between arguments (e.g., to specify
* required, exclusive, or dependent argument sets).
*
* @param parser The argument parser to be updated with the configuration
* arguments which may be used by this cipher stream provider.
*
* @throws ArgumentException If a problem is encountered while updating the
* provided argument parser.
*/
@Override()
public void defineConfigArguments(final ArgumentParser parser)
throws ArgumentException
{
// Add an argument that allows you to specify the subject attribute.
final Character shortIdentifier = null;
final String longIdentifier = ARG_NAME_KEY_PASSWORD;
final boolean required = true;
final int maxOccurrences = 1;
final String placeholder = "{password}";
final String description = "The password to use to generate the " +
"key to use for performing 128-bit AES encryption and decryption.";
parser.addArgument(new StringArgument(shortIdentifier, longIdentifier,
required, maxOccurrences, placeholder, description));
}
/**
* Initializes this cipher stream provider.
*
* @param serverContext A handle to the server context for the server in
* which this extension is running.
* @param config The general configuration for this cipher stream
* provider.
* @param parser The argument parser which has been initialized from
* the configuration for this cipher stream provider.
*
* @throws LDAPException If a problem occurs while initializing this cipher
* stream provider.
*/
@Override()
public void initializeCipherStreamProvider(
final DirectoryServerContext serverContext,
final CipherStreamProviderConfig config,
final ArgumentParser parser)
throws LDAPException
{
serverContext.debugInfo("Beginning cipher stream provider initialization");
this.serverContext = serverContext;
// Get the key password.
final StringArgument pwArg =
(StringArgument) parser.getNamedArgument(ARG_NAME_KEY_PASSWORD);
keyPassword = pwArg.getValue().toCharArray();
}
/**
* Indicates whether the configuration contained in the provided argument
* parser represents a valid configuration for this extension.
*
* @param config The general configuration for this cipher
* stream provider.
* @param parser The argument parser which has been initialized
* with the proposed configuration.
* @param unacceptableReasons A list that can be updated with reasons that
* the proposed configuration is not acceptable.
*
* @return {@code true} if the proposed configuration is acceptable, or
* {@code false} if not.
*/
@Override()
public boolean isConfigurationAcceptable(
final CipherStreamProviderConfig config,
final ArgumentParser parser,
final List<String> unacceptableReasons)
{
// This is a special case, because we don't want the password to be changed
// once it is set. If the password is changed in the same configuration
// entry (rather than defining a new configuration entry with the new
// password), then it may no longer be possible to decrypt any data that was
// previously encrypted with the old key. As a result, we will only allow
// the password change if there is no current configuration (which would be
// the case when first initializing this cipher stream provider), or if the
// new configuration has the same password as the previous one.
if (keyPassword == null)
{
return true;
}
final StringArgument pwArg =
(StringArgument) parser.getNamedArgument(ARG_NAME_KEY_PASSWORD);
final String newPW = pwArg.getValue();
if (newPW.equals(new String(keyPassword)))
{
return true;
}
else
{
unacceptableReasons.add("The password used for the cipher stream " +
"provider must not be changed once it has been set, because it " +
"can prevent previously-encrypted data from being decrypted. " +
"Instead, a new cipher stream provider instance should be " +
"created and configured for use.");
return false;
}
}
/**
* Attempts to apply the configuration contained in the provided argument
* parser.
*
* @param config The general configuration for this cipher
* stream provider.
* @param parser The argument parser which has been
* initialized with the new configuration.
* @param adminActionsRequired A list that can be updated with information
* about any administrative actions that may be
* required before one or more of the
* configuration changes will be applied.
* @param messages A list that can be updated with information
* about the result of applying the new
* configuration.
*
* @return A result code that provides information about the result of
* attempting to apply the configuration change.
*/
@Override()
public ResultCode applyConfiguration(final CipherStreamProviderConfig config,
final ArgumentParser parser,
final List<String> adminActionsRequired,
final List<String> messages)
{
// We will not apply any configuration change, so just return success
// without doing anything.
return ResultCode.SUCCESS;
}
/**
* Performs any cleanup which may be necessary when this cipher stream
* provider is to be taken out of service.
*/
@Override()
public void finalizeCipherStreamProvider()
{
// No finalization is required.
}
/**
* Wraps the provided input stream in a cipher input stream that can be used
* to decrypt data read from the given stream.
*
* @param source The input stream to be wrapped with a cipher input stream.
*
* @return The cipher input stream which wraps the provided input stream.
*
* @throws LDAPException If a problem occurs while creating the cipher input
* stream.
*/
@Override()
public CipherInputStream createCipherInputStream(final InputStream source)
throws LDAPException
{
final Cipher cipher;
try
{
final SecretKeyFactory keyFactory =
SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
final PBEKeySpec keySpec = new PBEKeySpec(keyPassword, new byte[8],
1024, 128);
final SecretKey encryptionKey =
new SecretKeySpec(keyFactory.generateSecret(keySpec).getEncoded(),
"AES");
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.DECRYPT_MODE, encryptionKey);
}
catch (final Exception e)
{
serverContext.debugCaught(e);
throw new LDAPException(ResultCode.OTHER,
"An error occurred while attempting to create the encryption " +
"cipher: " + StaticUtils.getExceptionMessage(e),
e);
}
return new CipherInputStream(source, cipher);
}
/**
* Wraps the provided output stream in a cipher output stream that can be used
* to encrypt data written to the given stream.
*
* @param target The output stream to be wrapped with a cipher output
* stream.
*
* @return The cipher output stream which wraps the provided output stream.
*
* @throws LDAPException If a problem occurs while creating the cipher
* output stream.
*/
@Override()
public CipherOutputStream createCipherOutputStream(final OutputStream target)
throws LDAPException
{
final Cipher cipher;
try
{
final SecretKeyFactory keyFactory =
SecretKeyFactory.getInstance("PBKDF2WithHmacSHA1");
final PBEKeySpec keySpec = new PBEKeySpec(keyPassword, new byte[8],
1024, 128);
final SecretKey encryptionKey =
new SecretKeySpec(keyFactory.generateSecret(keySpec).getEncoded(),
"AES");
cipher = Cipher.getInstance("AES");
cipher.init(Cipher.ENCRYPT_MODE, encryptionKey);
}
catch (final Exception e)
{
serverContext.debugCaught(e);
throw new LDAPException(ResultCode.OTHER,
"An error occurred while attempting to create the decryption " +
"cipher: " + StaticUtils.getExceptionMessage(e),
e);
}
return new CipherOutputStream(target, cipher);
}
/**
* Retrieves a map containing examples of configurations that may be used for
* this extension. The map key should be a list of sample arguments, and the
* corresponding value should be a description of the behavior that will be
* exhibited by the extension when used with that configuration.
*
* @return A map containing examples of configurations that may be used for
* this extension. It may be {@code null} or empty if there should
* not be any example argument sets.
*/
@Override()
public Map<List<String>,String> getExamplesArgumentSets()
{
final LinkedHashMap<List<String>,String> exampleMap =
new LinkedHashMap<List<String>,String>(1);
exampleMap.put(Arrays.asList(ARG_NAME_KEY_PASSWORD + "=secret123"),
"Use the password 'secret123' to generate the key to use when " +
"encrypting and decrypting data using a 128-bit AES cipher.");
return exampleMap;
}
}
