page.title=Security Enhancements in Android 5.0
@jd:body

<p>Every Android release includes dozens of security enhancements to protect
users.  Here are some of the major security enhancements available in Android
5.0:</p>

<ul>
  <li><strong>Encrypted by default.</strong> On devices that ship with L
out-of-the-box, full disk encryption is enabled by default to improve
protection of data on lost or stolen devices. Devices that
update to L can be encrypted in <strong>Settings</strong> &gt; <strong>Security</strong>. 
  <li><strong>Improved full disk encryption.</strong> The user password is
protected against brute-force attacks using <code>scrypt</code> and, where
available, the key is bound to the hardware keystore to prevent
off-device attacks.  As always, the Android screen lock secret and the device
encryption key are not sent off the device or exposed to any application.
  <li><strong>Android sandbox reinforced with SELinux</strong>. Android now
requires SELinux in enforcing mode for all domains. SELinux is a
mandatory access control (MAC) system in the Linux kernel used to augment the
existing discretionary access control (DAC) security model. This new layer
provides additional protection against potential security vulnerabilities.
  <li><strong>Smart Lock. </strong>Android now includes trustlets that provide
more flexibility for unlocking devices.  For example, trustlets can allow
devices to be unlocked automatically when close to another trusted device (via
NFC, Bluetooth) or being used by someone with a trusted face.
  <li><strong>Multi user, restricted profile, and guest modes for phones &
tablets.</strong> Android now provides for multiple users on phones and
includes a guest mode that can be used to provide easy temporary access to your
device without granting access to your data and apps.
  <li><strong>Updates to WebView without OTA. </strong> WebView can now be
updated independent of the framework and without a system
OTA.  This will allow for faster response to potential security issues in
WebView.
  <li><strong>Updated cryptography for HTTPS and TLS/SSL.</strong> TLSv1.2 and
TLSv1.1 is now enabled, Forward Secrecy is now preferred, AES-GCM
is now enabled, and weak cipher suites (MD5, 3DES, and export cipher suites)
are now disabled. See <a
href="https://developer.android.com/reference/javax/net/ssl/SSLSocket.html">https://developer.android.com/reference/javax/net/ssl/SSLSocket.html</a>
for more details.
  <li><strong>non-PIE linker support removed.</strong> Android now requires all
dynamically linked executables to support PIE
(position-independent executables). This enhances Android’s address space
layout randomization (ASLR) implementation.
  <li><strong>FORTIFY_SOURCE improvements.</strong> The following libc
functions now implement FORTIFY_SOURCE protections: <code>stpcpy()</code>,
<code>stpncpy()</code>, <code>read()</code>, <code>recvfrom()</code>,
<code>FD_CLR()</code>, <code>FD_SET()</code>, and <code>FD_ISSET()</code>. This
provides protection against memory-corruption vulnerabilities involving
those functions.
  <li><strong>Security Fixes.</strong> Android 5.0 also includes fixes for
Android-specific vulnerabilities. Information about these vulnerabilities has
been provided to Open Handset Alliance members, and fixes are available in
Android Open Source Project. To improve security, some devices with earlier
versions of Android may also include these fixes.
</ul>