https://source.android.com/ 
/*
 * Copyright 2017 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package android.privacy;


An interface for differential privacy encoder.
Applications can use it to convert privacy sensitive data to privacy protected report.
There is no decoder implemented in Android as it is not possible decode a single report by
design.

Each type of log should have its own encoder, otherwise it may leak
some information about Permanent Randomized Response(PRR, is used to create a “noisy”
answer which is memoized by the client and permanently reused in place of the real answer).

Some encoders may not support all encoding methods, and it will throw UnsupportedOperationException if you call unsupported encoding method. 
WARNING: Privacy protection works only when encoder uses a suitable DP configuration,
and the configuration and algorithm that is suitable is highly dependent on the use case.
If the configuration is not suitable for the use case, it may hurt privacy or utility or both.

@hide
/**
 * An interface for differential privacy encoder.
 * Applications can use it to convert privacy sensitive data to privacy protected report.
 * There is no decoder implemented in Android as it is not possible decode a single report by
 * design.
 *
 * <p>Each type of log should have its own encoder, otherwise it may leak
 * some information about Permanent Randomized Response(PRR, is used to create a “noisy”
 * answer which is memoized by the client and permanently reused in place of the real answer).
 *
 * <p>Some encoders may not support all encoding methods, and it will throw {@link
 * UnsupportedOperationException} if you call unsupported encoding method.
 *
 * <p><b>WARNING:</b> Privacy protection works only when encoder uses a suitable DP configuration,
 * and the configuration and algorithm that is suitable is highly dependent on the use case.
 * If the configuration is not suitable for the use case, it may hurt privacy or utility or both.
 *
 * @hide
 */
public interface DifferentialPrivacyEncoder {

    
Apply differential privacy to encode a string.

Params:
  • original – An arbitrary string
Returns:Differential privacy encoded bytes derived from the string
/**
     * Apply differential privacy to encode a string.
     *
     * @param original An arbitrary string
     * @return Differential privacy encoded bytes derived from the string
     */
    byte[] encodeString(String original);

    
Apply differential privacy to encode a boolean.

Params:
  • original – An arbitrary boolean.
Returns:Differential privacy encoded bytes derived from the boolean
/**
     * Apply differential privacy to encode a boolean.
     *
     * @param original An arbitrary boolean.
     * @return Differential privacy encoded bytes derived from the boolean
     */
    byte[] encodeBoolean(boolean original);

    
Apply differential privacy to encode sequence of bytes.

Params:
  • original – An arbitrary byte array.
Returns:Differential privacy encoded bytes derived from the bytes
/**
     * Apply differential privacy to encode sequence of bytes.
     *
     * @param original An arbitrary byte array.
     * @return Differential privacy encoded bytes derived from the bytes
     */
    byte[] encodeBits(byte[] original);

    
Returns the configuration that this encoder is using.

/**
     * Returns the configuration that this encoder is using.
     */
    DifferentialPrivacyConfig getConfig();

    
Return True if the output from encoder is NOT securely randomized, otherwise encoder should
be secure to randomize input.
 A non-secure encoder is intended only for testing only and must not be used to process
real data.


/**
     * Return True if the output from encoder is NOT securely randomized, otherwise encoder should
     * be secure to randomize input.
     *
     * <b> A non-secure encoder is intended only for testing only and must not be used to process
     * real data.
     * </b>
     */
    boolean isInsecureEncoderForTest();
}