en/security/encryption/adiantum.html - platform/docs/source.android.com - Git at Google

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     <title>Enabling Adiantum</title>
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 <p>
 <a href="https://eprint.iacr.org/2018/720.pdf" class="external">Adiantum</a>
   is an encryption method designed for devices running Android 9 and higher
   whose CPUs lack
   <a href="https://en.wikipedia.org/wiki/Advanced_Encryption_Standard"
      class="external">AES</a> instructions. If you are shipping an ARM-based
   device with ARMv8 Cryptography Extensions or an x86-based device with AES-NI,
   you should <strong>not</strong> use Adiantum. AES is faster on those
   platforms.
 </p>
 <p>
   For devices lacking these AES CPU instructions, Adiantum provides encryption on
   your device with very little performance overhead. For benchmarking numbers,
   see the <a href="https://eprint.iacr.org/2018/720.pdf"
              class="external">Adiantum paper</a>. For the benchmarking source
   to run on your hardware, see the
   <a href="https://github.com/google/adiantum" class="external">Adiantum source
     on GitHub</a>.
 </p>
 <p>
   To enable Adiantum on a device running Android 9 or higher, you need to
   make kernel changes and userspace changes.
 </p>

 <h2 id="kernel-changes">Kernel changes</h2>
 <p>
   Cherry-pick the Adiantum changes to your kernel and apply an additional
   <code>dm-crypt</code> patch. If you're having trouble cherry-picking, devices
   using <a href="https://source.android.com/security/encryption/full-disk"
            class="external">full-disk encryption</a> (FDE) can exclude the
   "fscrypt: " patch.
 </p>

 <table>
   <tr>
    <th>Kernel version</th>
     <th>Kernel changes</th>
     <th><code>dm-crypt</code> patch</th>
   </tr>
   <tr>
    <td>4.19
    </td>
    <td><a href="https://android-review.googlesource.com/q/topic:%22adiantum-4.19%22+(status:open%20OR%20status:merged)"
           class="external">4.19 kernel</a>
    </td>
    <td><a href="https://android-review.googlesource.com/c/kernel/common/+/851273"
           class="external"><code>dm-crypt</code> patch</a>
    </td>
   </tr>
   <tr>
    <td>4.14
    </td>
    <td><a href="https://android-review.googlesource.com/q/topic:%22adiantum-4.14%22+(status:open%20OR%20status:merged)"
           class="external">4.14 kernel</a>
    </td>
    <td><a href="https://android-review.googlesource.com/c/kernel/common/+/851275"
           class="external"><code>dm-crypt</code> patch</a>
    </td>
   </tr>
   <tr>
    <td>4.9
    </td>
    <td><a href="https://android-review.googlesource.com/q/topic:%22adiantum-4.9%22+(status:open%20OR%20status:merged)"
           class="external">4.9 kernel</a>
    </td>
    <td><a href="https://android-review.googlesource.com/c/kernel/common/+/851278"
           class="external"><code>dm-crypt</code> patch</a>
    </td>
   </tr>
 </table>

 <h3 id="enable-adiantum-kernel">Enable Adiantum in your kernel</h3>

 <p>
 After integrating the kernel changes, change your kernel config by adding the
 lines:
 </p>

 <pre class="devsite-click-to-copy">CONFIG_CRYPTO_ADIANTUM=y
 CONFIG_DM_CRYPT=y
 </pre>

 <p>
 If your device uses a 4.4 kernel, also add:
 </p>


 <pre class="devsite-click-to-copy">CONFIG_CRYPTO_SEQIV=y
 </pre>
 <p>
 If your device uses file-based encryption (FBE), also add:
 </p>


 <pre class="devsite-click-to-copy">CONFIG_F2FS_FS_ENCRYPTION=y
 </pre>
 <p>
 To ensure good performance on a 32-bit ARM kernel, enable NEON instructions for
 the kernel:
 </p>


 <pre
 class="devsite-click-to-copy">CONFIG_CRYPTO_AES_ARM=y
 CONFIG_CRYPTO_CHACHA20_NEON=y
 CONFIG_CRYPTO_NHPOLY1305_NEON=y
 CONFIG_KERNEL_MODE_NEON=y
 </pre>

 <h2 id="userspace-changes">Userspace changes</h2>
 <p>
   For devices running Android 9, cherry-pick the
   <a href="https://android-review.googlesource.com/q/topic:%22userspace_adiantum_support_pie%22+(status:open%20OR%20status:merged)"
      class="external">Adiantum userspace changes</a> in the
   <code>userspace_adiantum_support_pie</code> topic on the
   <code>pie-platform-release</code> branch in AOSP.
 </p>
 <p>
 These changes are also in the
   <a href="https://android-review.googlesource.com/q/topic:%22userspace_adiantum_support%22+(status:open%20OR%20status:merged)"
      class="external">master branch of AOSP</a>.
 </p>

 <h2 id="enable-adiantum-device">Enable Adiantum in your device</h2>
 <p>
 These settings are for the userdata on the device, and also for adoptable
 storage.
 </p>

 <h3 id="fbe-devices">Devices with file-based encryption</h3>
 <p>
 To enable Adiantum and improve its performance, set these properties in
 <code>PRODUCT_PROPERTY_OVERRIDES</code>:
 </p>


 <pre
 class="devsite-click-to-copy">ro.crypto.fde_algorithm=adiantum
 ro.crypto.fde_sector_size=4096
 ro.crypto.volume.contents_mode=adiantum
 ro.crypto.volume.filenames_mode=adiantum
 </pre>

 <aside class="caution"><strong>Important</strong>:
 This setting references FDE but is needed also on FBE devices; it
 affects adoptable storage.
 </aside>

 <p>
 Setting <code>fde_sector_size</code> to 4096 improves performance, but is not
 required for Adiantum to work.
 </p>
 <p>
   In the <code>fstab</code>, for userdata use the option:
 </p>


 <pre class="devsite-click-to-copy">fileencryption=adiantum
 </pre>
 <p>
 To verify that your implementation worked, take a bug report or run:
 </p>


 <pre class="devsite-click-to-copy">
 <code class="devsite-terminal">adb root</code>
 <code class="devsite-terminal">adb shell dmesg</code>
 </pre>
 <p>
 If Adiantum is enabled correctly, you should see this in the kernel log:
 </p>


 <pre
 class="devsite-click-to-copy">fscrypt: Adiantum using implementation "adiantum(xchacha12-neon,aes-arm,nhpoly1305-neon)"
 </pre>

 <aside class="note">
 <strong>Note</strong>: For ARM-based devices, the implementation name should
 match exactly. If you don't see references to <code>neon</code>, your device
 won't perform as well. See the <em><a href="#enable-adiantum-kernel">Enable
 Adiantum in your kernel</a></em> section for details on enabling NEON
 instructions.
 </aside>

 <h3 id="fde-devices">Devices with full-disk encryption</h3>
 <p>
 To enable Adiantum and improve its performance, set these properties in
 <code>PRODUCT_PROPERTY_OVERRIDES</code>:
 </p>


 <pre
 class="devsite-click-to-copy">ro.crypto.fde_algorithm=adiantum
 ro.crypto.fde_sector_size=4096
 </pre>
 <p>
 Setting <code>fde_sector_size</code> to 4096 improves performance, but is not
 required for Adiantum to work. To use this setting, the userdata partition must
 begin at a 4096-byte aligned offset on-disk.
 </p>
 <p>
 In the <code>fstab</code>, for userdata set:
 </p>


 <pre class="devsite-click-to-copy">forceencrypt
 </pre>
 <p>
 To verify that your implementation worked, take a bug report or run:
 </p>

 <pre class="devsite-click-to-copy">
 <code class="devsite-terminal">adb root</code>
 <code class="devsite-terminal">adb shell dmesg</code>
 </pre>

 <p>
 If Adiantum is enabled correctly, you should see this in the kernel log:
 </p>


 <pre
 class="devsite-click-to-copy">device-mapper: crypt: adiantum(xchacha12,aes) using implementation "adiantum(xchacha12-neon,aes-arm,nhpoly1305-neon)"
 </pre>
 <aside class="note">
 <strong>Note</strong>: For ARM-based devices, the implementation name should
 match exactly. If you don't see references to <code>neon</code>, your device
 won't perform as well. See the <em><a href="#enable-adiantum-kernel">Enable
 Adiantum in your kernel</a></em> section for details on enabling NEON
 instructions.
 </aside>
   </body>
 </html>
	<html devsite>
	<head>
	<title>Enabling Adiantum</title>
	<meta name="project_path" value="/_project.yaml" />
	<meta name="book_path" value="/_book.yaml" />
	</head>
	<body>
	<!--
	Copyright 2018 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.
	-->

	<p>
	<a href="https://eprint.iacr.org/2018/720.pdf" class="external">Adiantum</a>
	is an encryption method designed for devices running Android 9 and higher
	whose CPUs lack
	<a href="https://en.wikipedia.org/wiki/Advanced_Encryption_Standard"
	class="external">AES</a> instructions. If you are shipping an ARM-based
	device with ARMv8 Cryptography Extensions or an x86-based device with AES-NI,
	you should <strong>not</strong> use Adiantum. AES is faster on those
	platforms.
	</p>
	<p>
	For devices lacking these AES CPU instructions, Adiantum provides encryption on
	your device with very little performance overhead. For benchmarking numbers,
	see the <a href="https://eprint.iacr.org/2018/720.pdf"
	class="external">Adiantum paper</a>. For the benchmarking source
	to run on your hardware, see the
	<a href="https://github.com/google/adiantum" class="external">Adiantum source
	on GitHub</a>.
	</p>
	<p>
	To enable Adiantum on a device running Android 9 or higher, you need to
	make kernel changes and userspace changes.
	</p>

	<h2 id="kernel-changes">Kernel changes</h2>
	<p>
	Cherry-pick the Adiantum changes to your kernel and apply an additional
	<code>dm-crypt</code> patch. If you're having trouble cherry-picking, devices
	using <a href="https://source.android.com/security/encryption/full-disk"
	class="external">full-disk encryption</a> (FDE) can exclude the
	"fscrypt: " patch.
	</p>

	<table>
	<tr>
	<th>Kernel version</th>
	<th>Kernel changes</th>
	<th><code>dm-crypt</code> patch</th>
	</tr>
	<tr>
	<td>4.19
	</td>
	<td><a href="https://android-review.googlesource.com/q/topic:%22adiantum-4.19%22+(status:open%20OR%20status:merged)"
	class="external">4.19 kernel</a>
	</td>
	<td><a href="https://android-review.googlesource.com/c/kernel/common/+/851273"
	class="external"><code>dm-crypt</code> patch</a>
	</td>
	</tr>
	<tr>
	<td>4.14
	</td>
	<td><a href="https://android-review.googlesource.com/q/topic:%22adiantum-4.14%22+(status:open%20OR%20status:merged)"
	class="external">4.14 kernel</a>
	</td>
	<td><a href="https://android-review.googlesource.com/c/kernel/common/+/851275"
	class="external"><code>dm-crypt</code> patch</a>
	</td>
	</tr>
	<tr>
	<td>4.9
	</td>
	<td><a href="https://android-review.googlesource.com/q/topic:%22adiantum-4.9%22+(status:open%20OR%20status:merged)"
	class="external">4.9 kernel</a>
	</td>
	<td><a href="https://android-review.googlesource.com/c/kernel/common/+/851278"
	class="external"><code>dm-crypt</code> patch</a>
	</td>
	</tr>
	</table>

	<h3 id="enable-adiantum-kernel">Enable Adiantum in your kernel</h3>

	<p>
	After integrating the kernel changes, change your kernel config by adding the
	lines:
	</p>

	<pre class="devsite-click-to-copy">CONFIG_CRYPTO_ADIANTUM=y
	CONFIG_DM_CRYPT=y
	</pre>

	<p>
	If your device uses a 4.4 kernel, also add:
	</p>


	<pre class="devsite-click-to-copy">CONFIG_CRYPTO_SEQIV=y
	</pre>
	<p>
	If your device uses file-based encryption (FBE), also add:
	</p>


	<pre class="devsite-click-to-copy">CONFIG_F2FS_FS_ENCRYPTION=y
	</pre>
	<p>
	To ensure good performance on a 32-bit ARM kernel, enable NEON instructions for
	the kernel:
	</p>


	<pre
	class="devsite-click-to-copy">CONFIG_CRYPTO_AES_ARM=y
	CONFIG_CRYPTO_CHACHA20_NEON=y
	CONFIG_CRYPTO_NHPOLY1305_NEON=y
	CONFIG_KERNEL_MODE_NEON=y
	</pre>

	<h2 id="userspace-changes">Userspace changes</h2>
	<p>
	For devices running Android 9, cherry-pick the
	<a href="https://android-review.googlesource.com/q/topic:%22userspace_adiantum_support_pie%22+(status:open%20OR%20status:merged)"
	class="external">Adiantum userspace changes</a> in the
	<code>userspace_adiantum_support_pie</code> topic on the
	<code>pie-platform-release</code> branch in AOSP.
	</p>
	<p>
	These changes are also in the
	<a href="https://android-review.googlesource.com/q/topic:%22userspace_adiantum_support%22+(status:open%20OR%20status:merged)"
	class="external">master branch of AOSP</a>.
	</p>

	<h2 id="enable-adiantum-device">Enable Adiantum in your device</h2>
	<p>
	These settings are for the userdata on the device, and also for adoptable
	storage.
	</p>

	<h3 id="fbe-devices">Devices with file-based encryption</h3>
	<p>
	To enable Adiantum and improve its performance, set these properties in
	<code>PRODUCT_PROPERTY_OVERRIDES</code>:
	</p>


	<pre
	class="devsite-click-to-copy">ro.crypto.fde_algorithm=adiantum
	ro.crypto.fde_sector_size=4096
	ro.crypto.volume.contents_mode=adiantum
	ro.crypto.volume.filenames_mode=adiantum
	</pre>

	<aside class="caution"><strong>Important</strong>:
	This setting references FDE but is needed also on FBE devices; it
	affects adoptable storage.
	</aside>

	<p>
	Setting <code>fde_sector_size</code> to 4096 improves performance, but is not
	required for Adiantum to work.
	</p>
	<p>
	In the <code>fstab</code>, for userdata use the option:
	</p>


	<pre class="devsite-click-to-copy">fileencryption=adiantum
	</pre>
	<p>
	To verify that your implementation worked, take a bug report or run:
	</p>


	<pre class="devsite-click-to-copy">
	<code class="devsite-terminal">adb root</code>
	<code class="devsite-terminal">adb shell dmesg</code>
	</pre>
	<p>
	If Adiantum is enabled correctly, you should see this in the kernel log:
	</p>


	<pre
	class="devsite-click-to-copy">fscrypt: Adiantum using implementation "adiantum(xchacha12-neon,aes-arm,nhpoly1305-neon)"
	</pre>

	<aside class="note">
	<strong>Note</strong>: For ARM-based devices, the implementation name should
	match exactly. If you don't see references to <code>neon</code>, your device
	won't perform as well. See the <em><a href="#enable-adiantum-kernel">Enable
	Adiantum in your kernel</a></em> section for details on enabling NEON
	instructions.
	</aside>

	<h3 id="fde-devices">Devices with full-disk encryption</h3>
	<p>
	To enable Adiantum and improve its performance, set these properties in
	<code>PRODUCT_PROPERTY_OVERRIDES</code>:
	</p>


	<pre
	class="devsite-click-to-copy">ro.crypto.fde_algorithm=adiantum
	ro.crypto.fde_sector_size=4096
	</pre>
	<p>
	Setting <code>fde_sector_size</code> to 4096 improves performance, but is not
	required for Adiantum to work. To use this setting, the userdata partition must
	begin at a 4096-byte aligned offset on-disk.
	</p>
	<p>
	In the <code>fstab</code>, for userdata set:
	</p>


	<pre class="devsite-click-to-copy">forceencrypt
	</pre>
	<p>
	To verify that your implementation worked, take a bug report or run:
	</p>

	<pre class="devsite-click-to-copy">
	<code class="devsite-terminal">adb root</code>
	<code class="devsite-terminal">adb shell dmesg</code>
	</pre>

	<p>
	If Adiantum is enabled correctly, you should see this in the kernel log:
	</p>


	<pre
	class="devsite-click-to-copy">device-mapper: crypt: adiantum(xchacha12,aes) using implementation "adiantum(xchacha12-neon,aes-arm,nhpoly1305-neon)"
	</pre>
	<aside class="note">
	<strong>Note</strong>: For ARM-based devices, the implementation name should
	match exactly. If you don't see references to <code>neon</code>, your device
	won't perform as well. See the <em><a href="#enable-adiantum-kernel">Enable
	Adiantum in your kernel</a></em> section for details on enabling NEON
	instructions.
	</aside>
	</body>
	</html>