Merge "SyntheticPasswordManager: rename derivePassword() to deriveSubkey()" am: a2f9e65a02

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/2132301

Change-Id: Ibcb7bcbc87ae4754adf311beaaef1c2f0f5ce105
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>

1 files changed, 11 insertions, 7 deletions

diff --git a/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java b/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java
index 601a5727e545..111ffd29228c 100644
--- a/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java
+++ b/services/core/java/com/android/server/locksettings/SyntheticPasswordManager.java
@@ -186,7 +186,11 @@ public class SyntheticPasswordManager {
             mVersion = version;
         }
 
-        private byte[] derivePassword(byte[] personalization) {
+        /**
+         * Derives a subkey from the synthetic password. For v3 and later synthetic passwords the
+         * subkeys are 256-bit; for v1 and v2 they are 512-bit.
+         */
+        private byte[] deriveSubkey(byte[] personalization) {
             if (mVersion == SYNTHETIC_PASSWORD_VERSION_V3) {
                 return (new SP800Derive(mSyntheticPassword))
                     .withContext(personalization, PERSONALISATION_CONTEXT);
@@ -197,28 +201,28 @@ public class SyntheticPasswordManager {
         }
 
         public byte[] deriveKeyStorePassword() {
-            return bytesToHex(derivePassword(PERSONALIZATION_KEY_STORE_PASSWORD));
+            return bytesToHex(deriveSubkey(PERSONALIZATION_KEY_STORE_PASSWORD));
         }
 
         public byte[] deriveGkPassword() {
-            return derivePassword(PERSONALIZATION_SP_GK_AUTH);
+            return deriveSubkey(PERSONALIZATION_SP_GK_AUTH);
         }
 
         public byte[] deriveDiskEncryptionKey() {
-            return derivePassword(PERSONALIZATION_FBE_KEY);
+            return deriveSubkey(PERSONALIZATION_FBE_KEY);
         }
 
         public byte[] deriveVendorAuthSecret() {
-            return derivePassword(PERSONALIZATION_AUTHSECRET_KEY);
+            return deriveSubkey(PERSONALIZATION_AUTHSECRET_KEY);
         }
 
         public byte[] derivePasswordHashFactor() {
-            return derivePassword(PERSONALIZATION_PASSWORD_HASH);
+            return deriveSubkey(PERSONALIZATION_PASSWORD_HASH);
         }
 
         /** Derives key used to encrypt password metrics */
         public byte[] deriveMetricsKey() {
-            return derivePassword(PERSONALIZATION_PASSWORD_METRICS);
+            return deriveSubkey(PERSONALIZATION_PASSWORD_METRICS);
         }
 
         /**