com.google.crypto.tink.integration.android

Class SharedPrefKeysetWriter

java.lang.Object

com.google.crypto.tink.integration.android.SharedPrefKeysetWriter

All Implemented Interfaces:

KeysetWriter

public final class SharedPrefKeysetWriter
extends Object
implements KeysetWriter

A KeysetWriter that can write keysets to private shared preferences on Android.

We do not recommend new uses of this class. Instead, if you want to store a Tink keyset in shared preferences, serialize the keyset using TinkProtoKeysetFormat, and write it hex-encoded into your SharedPreferences manually.

For example, to write an encrypted keyset to the shared preferences, you can replace this:

 keysetHandle.write(
     new SharedPrefKeysetWriter(
         ApplicationProvider.getApplicationContext(), keysetName, null),
     keysetEncryptionAead);
 

with this:

 byte[] encryptedKeyset =
     TinkProtoKeysetFormat.serializeEncryptedKeyset(
         handle, keysetEncryptionAead, new byte[0]);
 SharedPreferences.Editor editor =
     PreferenceManager.getDefaultSharedPreferences(
             ApplicationProvider.getApplicationContext().getApplicationContext())
         .edit();
 boolean success = editor.putString(keysetName, Hex.encode(encryptedKeyset)).commit();
 

and to write an unencrypted keyset to the shared preferences, you can replace this:

 CleartextKeysetHandle.write(
     handle,
     new SharedPrefKeysetWriter(
         ApplicationProvider.getApplicationContext(), keysetName, null));
 

with this:

 byte[] serializedKeyset =
     TinkProtoKeysetFormat.serializeKeyset(handle, InsecureSecretKeyAccess.get());
 SharedPreferences.Editor editor =
     PreferenceManager.getDefaultSharedPreferences(
         ApplicationProvider.getApplicationContext().getApplicationContext())
     .edit();
 boolean success = editor.putString(keysetName, Hex.encode(serializedKeyset)).commit();
 

Constructor Summary

Constructors

Constructor and Description
SharedPrefKeysetWriter(Context context, String keysetName, String prefFileName) Creates a KeysetReader that hex-encodes and writes keysets to the preference name keysetName in the private shared preferences file prefFileName.

Method Summary

Modifier and Type	Method and Description
void	write(EncryptedKeyset keyset) Tries to write an EncryptedKeyset to some storage system.
void	write(Keyset keyset) Tries to write a Keyset to some storage system.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

SharedPrefKeysetWriter

public SharedPrefKeysetWriter(Context context,
                              String keysetName,
                              String prefFileName)

Creates a KeysetReader that hex-encodes and writes keysets to the preference name keysetName in the private shared preferences file prefFileName.

If prefFileName is null, uses the default shared preferences file.

Throws:

IOException - if cannot write the keyset

IllegalArgumentException - if keysetName is null

Method Detail

write

public void write(Keyset keyset)
           throws IOException

Description copied from interface: KeysetWriter

Tries to write a Keyset to some storage system.

Specified by:

write in interface KeysetWriter

Throws:

IOException

write

public void write(EncryptedKeyset keyset)
           throws IOException

Description copied from interface: KeysetWriter

Tries to write an EncryptedKeyset to some storage system.

Specified by:

write in interface KeysetWriter

Throws:

IOException