Add sshauthentication-api v1 support

sshauthentication-api/build.gradle

@@ -0,0 +1,36 @@
+apply plugin: 'com.android.library'
+
+buildscript {
+    repositories {
+        jcenter()
+    }
+    dependencies {
+        classpath 'com.android.tools.build:gradle:2.3.2'
+        // NOTE: Do not place application dependencies here
+    }
+}
+
+android {
+    if (project.hasProperty('rootProject.ext.compileSdkVersion')) {
+        compileSdkVersion rootProject.ext.compileSdkVersion
+    } else {
+        compileSdkVersion 25
+    }
+    if (project.hasProperty('rootProject.ext.buildToolsVersion')) {
+        buildToolsVersion rootProject.ext.buildToolsVersion
+    } else {
+        buildToolsVersion '25.0.2'
+    }
+
+    defaultConfig {
+        minSdkVersion 9
+        targetSdkVersion 25
+        versionCode 1
+        versionName "1.0"
+    }
+
+    // Do not abort build if lint finds errors
+    lintOptions {
+        abortOnError false
+    }
+}

sshauthentication-api/src/main/AndroidManifest.xml

@@ -0,0 +1,7 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+
+    package="org.openintents.ssh.authentication">
+
+    <application/>
+
+</manifest>

sshauthentication-api/src/main/aidl/org/openintents/ssh/authentication/ISshAuthenticationService.aidl

@@ -0,0 +1,6 @@
+// ISshAuthenticationService.aidl
+package org.openintents.ssh.authentication;
+
+interface ISshAuthenticationService {
+    Intent execute(in Intent intent);
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/SshAuthenticationApi.java

@@ -0,0 +1,219 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ * Copyright (C) 2017 Michael Perk
+ *
+ * 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 org.openintents.ssh.authentication;
+
+import android.annotation.TargetApi;
+import android.content.Context;
+import android.content.Intent;
+import android.os.AsyncTask;
+import android.os.Build;
+import android.util.Log;
+
+public class SshAuthenticationApi {
+    private static final String TAG = "SshAuthenticationApi";
+
+    public static final String SERVICE_INTENT = "org.openintents.ssh.authentication.ISshAuthenticationService";
+
+    public static final String EXTRA_API_VERSION = "api_version";
+    public static final int API_VERSION = 1;
+
+    public static final String EXTRA_RESULT_CODE = "result_code";
+    public static final int RESULT_CODE_ERROR = 0;
+    public static final int RESULT_CODE_SUCCESS = 1;
+    public static final int RESULT_CODE_USER_INTERACTION_REQUIRED = 2;
+
+    /**
+     * ACTION_SIGN
+     *
+     * Sign a given challenge
+     *
+     * required extras:
+     * String        EXTRA_KEY_ID
+     * byte[]        EXTRA_CHALLENGE
+     * int           EXTRA_HASH_ALGORITHM
+     *
+     * returned extras:
+     * byte[]        EXTRA_SIGNATURE
+     */
+    public static final String ACTION_SIGN = "org.openintents.ssh.action.SIGN";
+    public static final String EXTRA_CHALLENGE = "challenge";
+    public static final String EXTRA_HASH_ALGORITHM = "hash_algorithm";
+    public static final String EXTRA_SIGNATURE = "signature";
+
+    /* hash algorithms used in signature generation */
+    public static final int SHA1 = 0;
+    public static final int SHA224 = 1;
+    public static final int SHA256 = 2;
+    public static final int SHA384 = 3;
+    public static final int SHA512 = 4;
+    public static final int RIPEMD160 = 5;
+
+    /**
+     * ACTION_SELECT_KEY
+     *
+     * Select a key
+     *
+     * returned extras:
+     * String        EXTRA_KEY_ID
+     * String        EXTRA_KEY_DESCRIPTION
+     */
+    public static final String ACTION_SELECT_KEY = "org.openintents.ssh.action.SELECT_KEY";
+    public static final String EXTRA_KEY_DESCRIPTION = "key_description";
+
+    /**
+     * ACTION_GET_PUBLIC_KEY
+     *
+     * Get the public key for a key
+     *
+     * returns the public key encoded according to the ASN.1 type
+     * 'SubjectPublicKeyInfo' as defined in the X.509 standard,
+     * see RFC5280, RFC3279 and draft-ietf-curdle-pkix
+     * and their respective updates
+     *
+     * required extras:
+     * String        EXTRA_KEY_ID
+     *
+     * returned extras:
+     * byte[]        EXTRA_PUBLIC_KEY
+     * int           EXTRA_PUBLIC_KEY_ALGORITHM
+     */
+    public static final String ACTION_GET_PUBLIC_KEY = "org.openintents.ssh.action.GET_PUBLIC_KEY";
+    public static final String EXTRA_PUBLIC_KEY = "public_key";
+    public static final String EXTRA_PUBLIC_KEY_ALGORITHM = "public_key_algorithm";
+
+    /* public key algorithms */
+    public static final int RSA = 0;
+    public static final int ECDSA = 1;
+    public static final int EDDSA = 2;
+    public static final int DSA = 3;
+
+    /**
+     * ACTION_GET_SSH_PUBLIC_KEY
+     *
+     * Get the SSH public key for a key
+     *
+     * returns the public key in SSH public key format,
+     * as described in RFC4253, RFC5656 and draft-ietf-curdle-ssh-ed25519
+     * and their respective updates
+     *
+     * required extras:
+     * String        EXTRA_KEY_ID
+     *
+     * returned extras:
+     * String        EXTRA_SSH_PUBLIC_KEY
+     */
+    public static final String ACTION_GET_SSH_PUBLIC_KEY = "org.openintents.ssh.action.GET_SSH_PUBLIC_KEY";
+    public static final String EXTRA_SSH_PUBLIC_KEY = "ssh_public_key";
+
+    /**
+     * Error result of type SshAuthenticationApiError
+     */
+    public static final String EXTRA_ERROR = "error";
+
+    /**
+     * Pending Intent requiring user interaction
+     */
+    public static final String EXTRA_PENDING_INTENT = "intent";
+
+    /**
+     * Key identifier
+     */
+    public static final String EXTRA_KEY_ID = "key_id";
+
+
+    private final ISshAuthenticationService mService;
+    private final Context mContext;
+
+
+    public SshAuthenticationApi(Context context, ISshAuthenticationService service) {
+        mService = service;
+        mContext = context;
+    }
+
+    public interface ISshAgentCallback {
+        void onReturn(final Intent result);
+    }
+
+    private class SshAgentAsyncTask extends AsyncTask<Void, Integer, Intent> {
+        Intent data;
+        ISshAgentCallback callback;
+
+        private SshAgentAsyncTask(Intent data, ISshAgentCallback callback) {
+            this.data = data;
+            this.callback = callback;
+        }
+
+        @Override
+        protected Intent doInBackground(Void... unused) {
+            return executeApi(data);
+        }
+
+        protected void onPostExecute(Intent result) {
+            callback.onReturn(result);
+        }
+
+    }
+
+    @TargetApi(Build.VERSION_CODES.HONEYCOMB)
+    public void executeApiAsync(Intent data, ISshAgentCallback callback) {
+        SshAgentAsyncTask task = new SshAgentAsyncTask(data, callback);
+
+        // don't serialize async tasks, always execute them in parallel
+        // http://commonsware.com/blog/2012/04/20/asynctask-threading-regression-confirmed.html
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
+            task.executeOnExecutor(AsyncTask.THREAD_POOL_EXECUTOR, (Void[]) null);
+        } else {
+            task.execute((Void[]) null);
+        }
+    }
+
+    public Intent executeApi(Intent data) {
+        try {
+            // always send version from client
+            data.putExtra(SshAuthenticationApi.EXTRA_API_VERSION, SshAuthenticationApi.API_VERSION);
+
+            Intent result;
+
+            // blocks until result is ready
+            result = mService.execute(data);
+
+            // set class loader to current context to allow unparcelling of SshAuthenticationApiError
+            // http://stackoverflow.com/a/3806769
+            result.setExtrasClassLoader(mContext.getClassLoader());
+
+            return result;
+        } catch (Exception e) {
+            Log.e(TAG, "Exception in executeApi call", e);
+            return createExceptionErrorResult(SshAuthenticationApiError.CLIENT_SIDE_ERROR,
+                    "Exception in executeApi call", e);
+        }
+    }
+
+    private Intent createErrorResult(int errorCode, String errorMessage) {
+        Log.e(TAG, errorMessage);
+        Intent result = new Intent();
+        result.putExtra(SshAuthenticationApi.EXTRA_ERROR, new SshAuthenticationApiError(errorCode, errorMessage));
+        result.putExtra(SshAuthenticationApi.EXTRA_RESULT_CODE, SshAuthenticationApi.RESULT_CODE_ERROR);
+        return result;
+    }
+
+    private Intent createExceptionErrorResult(int errorCode, String errorMessage, Exception e) {
+        String message = errorMessage + " : " + e.getMessage();
+        return createErrorResult(errorCode, message);
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/SshAuthenticationApiError.java

@@ -0,0 +1,88 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication;
+
+import android.os.Parcel;
+import android.os.Parcelable;
+
+public class SshAuthenticationApiError implements Parcelable {
+
+    /**
+     * Error codes
+     */
+    /* values chosen for compatibility with openpgp-api */
+    public static final int CLIENT_SIDE_ERROR = -1;
+    public static final int GENERIC_ERROR = 0;
+    public static final int INCOMPATIBLE_API_VERSIONS = 1;
+    public static final int INTERNAL_ERROR = 2;
+
+    /* values chosen for no intersection with openpgp-api */
+    public static final int UNKNOWN_ACTION = -128;
+    public static final int NO_KEY_ID = -129;
+    public static final int NO_SUCH_KEY = -130;
+    public static final int NO_AUTH_KEY = -131;
+
+    /* values chosen to be invalid enumeration values in their respective domain */
+    public static final int INVALID_ALGORITHM = -254;
+    public static final int INVALID_HASH_ALGORITHM = -253;
+
+
+    private int mError;
+    private String mMessage;
+
+
+    public SshAuthenticationApiError(int error, String message) {
+        mError = error;
+        mMessage = message;
+    }
+
+    protected SshAuthenticationApiError(Parcel in) {
+        mError = in.readInt();
+        mMessage = in.readString();
+    }
+
+    public static final Creator<SshAuthenticationApiError> CREATOR = new Creator<SshAuthenticationApiError>() {
+        @Override
+        public SshAuthenticationApiError createFromParcel(Parcel in) {
+            return new SshAuthenticationApiError(in);
+        }
+
+        @Override
+        public SshAuthenticationApiError[] newArray(int size) {
+            return new SshAuthenticationApiError[size];
+        }
+    };
+
+    public int getError() {
+        return mError;
+    }
+
+    public String getMessage() {
+        return mMessage;
+    }
+
+    @Override
+    public int describeContents() {
+        return 0;
+    }
+
+    @Override
+    public void writeToParcel(Parcel dest, int flags) {
+        dest.writeInt(mError);
+        dest.writeString(mMessage);
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/SshAuthenticationConnection.java

@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ * Copyright (C) 2017 Jonas Dippel
+ *
+ * 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 org.openintents.ssh.authentication;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.ServiceConnection;
+import android.os.IBinder;
+
+public class SshAuthenticationConnection {
+
+    private final Context mContext;
+    private final String mTargetPackage;
+
+    private ISshAuthenticationService mSSHAgent;
+
+    /**
+     * Callback for signaling connection events
+     */
+    public interface OnBound {
+        /**
+         * Called when the connection is bound to the service
+         *
+         * @param sshAgent the bound remote service stub
+         */
+        void onBound(ISshAuthenticationService sshAgent);
+
+        /**
+         * Called when the connection is disconnected due to some error
+         */
+        void onError();
+    }
+
+    private OnBound mOnBoundListener;
+
+    /**
+     * Construct an SshAuthenticationConnection instance with the desired attributes
+     *
+     * @param context       the application context
+     * @param targetPackage the package of the service to bind to
+     */
+    public SshAuthenticationConnection(Context context, String targetPackage) {
+        mContext = context;
+        mTargetPackage = targetPackage;
+    }
+
+    private final ServiceConnection mServiceConnection = new ServiceConnection() {
+        @Override
+        public void onServiceConnected(ComponentName name, IBinder service) {
+            mSSHAgent = ISshAuthenticationService.Stub.asInterface(service);
+            mOnBoundListener.onBound(mSSHAgent);
+        }
+
+        @Override
+        public void onServiceDisconnected(ComponentName name) {
+            mSSHAgent = null;
+            mOnBoundListener.onError();
+        }
+    };
+
+    /**
+     * Connect to the Service via a Connection
+     *
+     * @return false if service was not found or an error occured, else true
+     */
+    public boolean connect(final OnBound onBoundListener) {
+        mOnBoundListener = onBoundListener;
+		if (mSSHAgent == null) {
+            Intent intent = new Intent(SshAuthenticationApi.SERVICE_INTENT);
+            intent.setPackage(mTargetPackage);
+            return mContext.bindService(intent, mServiceConnection, Context.BIND_AUTO_CREATE);
+        } else {
+            mOnBoundListener.onBound(mSSHAgent);
+            return true;
+        }
+    }
+
+    /**
+     * Check whether the Connection is bound to a service
+     *
+     * @return whether the Connection is bound to a service
+     */
+    public boolean isConnected() {
+        return mSSHAgent != null;
+    }
+
+    public void disconnect() {
+        mSSHAgent = null;
+        mContext.unbindService(mServiceConnection);
+    }
+
+    public ISshAuthenticationService getService() {
+        return mSSHAgent;
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/request/KeySelectionRequest.java

@@ -0,0 +1,36 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.request;
+
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+
+public class KeySelectionRequest extends Request {
+
+    @Override
+    protected void getData(Intent intent) {
+    }
+
+    @Override
+    protected void putData(Intent request) {
+    }
+
+    @Override
+    protected String getAction() {
+        return SshAuthenticationApi.ACTION_SELECT_KEY;
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/request/PublicKeyRequest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.request;
+
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+
+public class PublicKeyRequest extends Request {
+
+    private String mKeyId;
+
+    public PublicKeyRequest(String keyId) {
+        mKeyId = keyId;
+    }
+
+    @Override
+    protected void getData(Intent intent) {
+        mKeyId = intent.getStringExtra(SshAuthenticationApi.EXTRA_KEY_ID);
+    }
+
+    @Override
+    protected void putData(Intent request) {
+        request.putExtra(SshAuthenticationApi.EXTRA_KEY_ID, mKeyId);
+    }
+
+    @Override
+    protected String getAction() {
+        return SshAuthenticationApi.ACTION_GET_PUBLIC_KEY;
+    }
+
+    public String getKeyID() {
+        return mKeyId;
+    }
+
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/request/Request.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.request;
+
+import android.content.Intent;
+
+public abstract class Request {
+
+    public Intent toIntent() {
+        Intent request = new Intent();
+        request.setAction(getAction());
+
+        putData(request);
+
+        return request;
+    }
+
+    private void populatefromIntent(Intent intent) {
+        getData(intent);
+    }
+
+    protected abstract void getData(Intent intent);
+
+    protected abstract void putData(Intent request);
+
+    protected abstract String getAction();
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/request/SigningRequest.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ * Copyright (C) 2017 Michael Perk
+ *
+ * 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 org.openintents.ssh.authentication.request;
+
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+import org.openintents.ssh.authentication.SshAuthenticationApiError;
+
+public class SigningRequest extends Request {
+
+    private byte[] mChallenge;
+    private String mKeyIdentifier;
+    private int mHashAlgorithm;
+
+    public SigningRequest(byte[] challenge, String keyIdentifier, int hashAlgorithm) {
+        mHashAlgorithm = hashAlgorithm;
+        mKeyIdentifier = keyIdentifier;
+        mChallenge = challenge;
+    }
+
+    @Override
+    protected String getAction() {
+        return SshAuthenticationApi.ACTION_SIGN;
+    }
+
+    @Override
+    protected void getData(Intent intent) {
+        mHashAlgorithm = intent.getIntExtra(SshAuthenticationApi.EXTRA_HASH_ALGORITHM, SshAuthenticationApiError.INVALID_HASH_ALGORITHM);
+        mKeyIdentifier = intent.getStringExtra(SshAuthenticationApi.EXTRA_KEY_ID);
+        mChallenge = intent.getByteArrayExtra(SshAuthenticationApi.EXTRA_CHALLENGE);
+    }
+
+    @Override
+    protected void putData(Intent request) {
+        request.putExtra(SshAuthenticationApi.EXTRA_HASH_ALGORITHM, mHashAlgorithm);
+        request.putExtra(SshAuthenticationApi.EXTRA_KEY_ID, mKeyIdentifier);
+        request.putExtra(SshAuthenticationApi.EXTRA_CHALLENGE, mChallenge);
+    }
+
+    public int getHashAlgorithm() {
+        return mHashAlgorithm;
+    }
+
+    public String getKeyIdentifier() {
+        return mKeyIdentifier;
+    }
+
+    public byte[] getChallenge() {
+        return mChallenge;
+    }
+
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/request/SshPublicKeyRequest.java

@@ -0,0 +1,49 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.request;
+
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+
+public class SshPublicKeyRequest extends Request {
+
+    private String mKeyId;
+
+    public SshPublicKeyRequest(String keyId) {
+        mKeyId = keyId;
+    }
+
+    @Override
+    protected void getData(Intent intent) {
+        mKeyId = intent.getStringExtra(SshAuthenticationApi.EXTRA_KEY_ID);
+    }
+
+    @Override
+    protected void putData(Intent request) {
+        request.putExtra(SshAuthenticationApi.EXTRA_KEY_ID, mKeyId);
+    }
+
+    @Override
+    protected String getAction() {
+        return SshAuthenticationApi.ACTION_GET_SSH_PUBLIC_KEY;
+    }
+
+    public String getKeyId() {
+        return mKeyId;
+    }
+
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/response/KeySelectionResponse.java

@@ -0,0 +1,66 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.response;
+
+import android.app.PendingIntent;
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+import org.openintents.ssh.authentication.SshAuthenticationApiError;
+
+public class KeySelectionResponse extends Response {
+
+    private String mKeyId;
+    private String mKeyDescription;
+
+    public KeySelectionResponse(Intent data) {
+        super(data);
+    }
+
+    public KeySelectionResponse(PendingIntent pendingIntent) {
+        super(pendingIntent);
+    }
+
+    public KeySelectionResponse(SshAuthenticationApiError error) {
+        super(error);
+    }
+
+    public KeySelectionResponse(String keyId, String keyDescription) {
+        super();
+        mKeyId = keyId;
+        mKeyDescription = keyDescription;
+    }
+
+    @Override
+    protected void getResults(Intent intent) {
+        mKeyId = intent.getStringExtra(SshAuthenticationApi.EXTRA_KEY_ID);
+        mKeyDescription = intent.getStringExtra(SshAuthenticationApi.EXTRA_KEY_DESCRIPTION);
+    }
+
+    @Override
+    protected void putResults(Intent intent) {
+        intent.putExtra(SshAuthenticationApi.EXTRA_KEY_ID, mKeyId);
+        intent.putExtra(SshAuthenticationApi.EXTRA_KEY_DESCRIPTION, mKeyDescription);
+    }
+
+    public String getKeyId() {
+        return mKeyId;
+    }
+
+    public String getKeyDescription() {
+        return mKeyDescription;
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/response/PublicKeyResponse.java

@@ -0,0 +1,68 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.response;
+
+import android.app.PendingIntent;
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+import org.openintents.ssh.authentication.SshAuthenticationApiError;
+
+public class PublicKeyResponse extends Response {
+    public static final int INVALID_ALGORITHM = SshAuthenticationApiError.INVALID_ALGORITHM;
+
+    private byte[] mEncodedPublicKey;
+    private int mKeyAlgorithm;
+
+    public PublicKeyResponse(Intent data) {
+        super(data);
+    }
+
+    public PublicKeyResponse(PendingIntent pendingIntent) {
+        super(pendingIntent);
+    }
+
+    public PublicKeyResponse(SshAuthenticationApiError error) {
+        super(error);
+    }
+
+    public PublicKeyResponse(byte[] encodedPublicKey,
+                             int keyAlgorithm) {
+        super();
+        mEncodedPublicKey = encodedPublicKey;
+        mKeyAlgorithm = keyAlgorithm;
+    }
+
+    @Override
+    protected void getResults(Intent intent) {
+        mEncodedPublicKey = intent.getByteArrayExtra(SshAuthenticationApi.EXTRA_PUBLIC_KEY);
+        mKeyAlgorithm = intent.getIntExtra(SshAuthenticationApi.EXTRA_PUBLIC_KEY_ALGORITHM, INVALID_ALGORITHM);
+    }
+
+    @Override
+    protected void putResults(Intent intent) {
+        intent.putExtra(SshAuthenticationApi.EXTRA_PUBLIC_KEY, mEncodedPublicKey);
+        intent.putExtra(SshAuthenticationApi.EXTRA_PUBLIC_KEY_ALGORITHM, mKeyAlgorithm);
+    }
+
+    public byte[] getEncodedPublicKey() {
+        return mEncodedPublicKey;
+    }
+
+    public int getKeyAlgorithm() {
+        return mKeyAlgorithm;
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/response/Response.java

@@ -0,0 +1,107 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.response;
+
+import android.app.PendingIntent;
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+import org.openintents.ssh.authentication.SshAuthenticationApiError;
+
+public abstract class Response {
+    public static final int RESULT_CODE_ERROR = SshAuthenticationApi.RESULT_CODE_ERROR;
+    public static final int RESULT_CODE_SUCCESS = SshAuthenticationApi.RESULT_CODE_SUCCESS;
+    public static final int RESULT_CODE_USER_INTERACTION_REQUIRED = SshAuthenticationApi.RESULT_CODE_USER_INTERACTION_REQUIRED;
+
+    protected int mResultCode;
+
+    protected PendingIntent mPendingIntent;
+
+    protected SshAuthenticationApiError mError;
+
+    protected Response() {
+        mResultCode = RESULT_CODE_SUCCESS;
+    }
+
+    public Response(Intent data) {
+        populateFromIntent(data);
+    }
+
+    public Response(PendingIntent pendingIntent) {
+        mPendingIntent = pendingIntent;
+        mResultCode = RESULT_CODE_USER_INTERACTION_REQUIRED;
+    }
+
+    public Response(SshAuthenticationApiError error) {
+        mError = error;
+        mResultCode = RESULT_CODE_ERROR;
+    }
+
+    private void populateFromIntent(Intent intent) {
+        int resultCode = intent.getIntExtra(SshAuthenticationApi.EXTRA_RESULT_CODE, SshAuthenticationApi.RESULT_CODE_ERROR);
+
+        switch (resultCode) {
+            case SshAuthenticationApi.RESULT_CODE_SUCCESS:
+                mResultCode = RESULT_CODE_SUCCESS;
+                getResults(intent);
+                break;
+            case SshAuthenticationApi.RESULT_CODE_USER_INTERACTION_REQUIRED:
+                mResultCode = RESULT_CODE_USER_INTERACTION_REQUIRED;
+                mPendingIntent = intent.getParcelableExtra(SshAuthenticationApi.EXTRA_PENDING_INTENT);
+                break;
+            case SshAuthenticationApi.RESULT_CODE_ERROR:
+                mResultCode = RESULT_CODE_ERROR;
+                mError = intent.getParcelableExtra(SshAuthenticationApi.EXTRA_ERROR);
+        }
+    }
+
+    public Intent toIntent() {
+        Intent intent = new Intent();
+
+        switch (mResultCode) {
+            case RESULT_CODE_SUCCESS:
+                intent.putExtra(SshAuthenticationApi.EXTRA_RESULT_CODE, SshAuthenticationApi.RESULT_CODE_SUCCESS);
+                putResults(intent);
+                break;
+            case RESULT_CODE_USER_INTERACTION_REQUIRED:
+                intent.putExtra(SshAuthenticationApi.EXTRA_RESULT_CODE, SshAuthenticationApi.RESULT_CODE_USER_INTERACTION_REQUIRED);
+                intent.putExtra(SshAuthenticationApi.EXTRA_PENDING_INTENT, mPendingIntent);
+                break;
+            case RESULT_CODE_ERROR:
+                intent.putExtra(SshAuthenticationApi.EXTRA_RESULT_CODE, SshAuthenticationApi.RESULT_CODE_ERROR);
+                intent.putExtra(SshAuthenticationApi.EXTRA_ERROR, mError);
+        }
+
+        return intent;
+    }
+
+    public int getResultCode() {
+        return mResultCode;
+    }
+
+    public PendingIntent getPendingIntent() {
+        return mPendingIntent;
+    }
+
+    public SshAuthenticationApiError getError() {
+        return mError;
+    }
+
+    protected abstract void getResults(Intent intent);
+
+    protected abstract void putResults(Intent intent);
+
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/response/SigningResponse.java

@@ -0,0 +1,60 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ * Copyright (C) 2017 Jonas Dippel, Michael Perk
+ *
+ * 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 org.openintents.ssh.authentication.response;
+
+import android.app.PendingIntent;
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+import org.openintents.ssh.authentication.SshAuthenticationApiError;
+
+public class SigningResponse extends Response {
+
+    private byte[] mSignature;
+
+    public SigningResponse(Intent data) {
+        super(data);
+    }
+
+    public SigningResponse(PendingIntent pendingIntent) {
+        super(pendingIntent);
+    }
+
+    public SigningResponse(SshAuthenticationApiError error) {
+        super(error);
+    }
+
+    public SigningResponse(byte[] signature) {
+        super();
+        mSignature = signature;
+    }
+
+    @Override
+    protected void getResults(Intent intent) {
+        mSignature = intent.getByteArrayExtra(SshAuthenticationApi.EXTRA_SIGNATURE);
+    }
+
+    @Override
+    protected void putResults(Intent intent) {
+        intent.putExtra(SshAuthenticationApi.EXTRA_SIGNATURE, mSignature);
+    }
+
+    public byte[] getSignature() {
+        return mSignature;
+    }
+
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/response/SshPublicKeyResponse.java

@@ -0,0 +1,58 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.response;
+
+import android.app.PendingIntent;
+import android.content.Intent;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+import org.openintents.ssh.authentication.SshAuthenticationApiError;
+
+public class SshPublicKeyResponse extends Response {
+
+    private String mSshPublicKey;
+
+    public SshPublicKeyResponse(Intent data) {
+        super(data);
+    }
+
+    public SshPublicKeyResponse(PendingIntent pendingIntent) {
+        super(pendingIntent);
+    }
+
+    public SshPublicKeyResponse(SshAuthenticationApiError error) {
+        super(error);
+    }
+
+    public SshPublicKeyResponse(String sshPublicKey) {
+        super();
+        mSshPublicKey = sshPublicKey;
+    }
+
+    @Override
+    protected void getResults(Intent intent) {
+        mSshPublicKey = intent.getStringExtra(SshAuthenticationApi.EXTRA_SSH_PUBLIC_KEY);
+    }
+
+    @Override
+    protected void putResults(Intent intent) {
+        intent.putExtra(SshAuthenticationApi.EXTRA_SSH_PUBLIC_KEY, mSshPublicKey);
+    }
+
+    public String getSshPublicKey() {
+        return mSshPublicKey;
+    }
+}

sshauthentication-api/src/main/java/org/openintents/ssh/authentication/util/SshAuthenticationApiUtils.java

@@ -0,0 +1,41 @@
+/*
+ * Copyright (C) 2017 Christian Hagau <ach@hagau.se>
+ *
+ * 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 org.openintents.ssh.authentication.util;
+
+import android.content.Context;
+import android.content.Intent;
+import android.content.pm.ResolveInfo;
+import org.openintents.ssh.authentication.SshAuthenticationApi;
+
+import java.util.ArrayList;
+import java.util.List;
+
+
+public class SshAuthenticationApiUtils {
+    public static List<String> getAgentProviders(Context context) {
+        Intent intent = new Intent(SshAuthenticationApi.SERVICE_INTENT);
+        List<ResolveInfo> resolvedInfo = context.getPackageManager().queryIntentServices(intent, 0);
+        ArrayList<String> providers = new ArrayList<>();
+        if (resolvedInfo != null) {
+            for (ResolveInfo resolveInfoEntry : resolvedInfo) {
+                providers.add(resolveInfoEntry.serviceInfo.packageName);
+            }
+        }
+        return providers;
+    }
+
+}