com.google.crypto.tink

Class KeyTypeManager.KeyFactory<KeyFormatProtoT extends com.google.protobuf.MessageLite,KeyT>

java.lang.Object

com.google.crypto.tink.KeyTypeManager.KeyFactory<KeyFormatProtoT,KeyT>

Enclosing class:

KeyTypeManager<KeyProtoT extends com.google.protobuf.MessageLite>

public abstract static class KeyTypeManager.KeyFactory<KeyFormatProtoT extends com.google.protobuf.MessageLite,KeyT>
extends Object

A KeyFactory creates new keys from a given KeyFormat.

A KeyFactory implements all the methods which are required if a KeyTypeManager should also be able to generate keys. In particular, in this case it needs to have some KeyFormat protocol buffer which can be validated, parsed, and from which a key can be generated.

Constructor Summary

Constructors

Constructor and Description
KeyFactory(Class<KeyFormatProtoT> clazz)

Method Summary

Modifier and Type	Method and Description
abstract KeyT	createKey(KeyFormatProtoT keyFormat) Creates a new key from a given format.
KeyT	deriveKey(KeyFormatProtoT keyFormat, InputStream pseudoRandomness) Derives a new key from a given format, using the given .
Class<KeyFormatProtoT>	getKeyFormatClass() Returns the class corresponding to the key format protobuffer.
abstract KeyFormatProtoT	parseKeyFormat(com.google.protobuf.ByteString byteString) Parses a serialized key proto.
abstract void	validateKeyFormat(KeyFormatProtoT keyFormatProto) Checks if the given keyFormatProto is a valid key.

Methods inherited from class java.lang.Object

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

Constructor Detail

KeyFactory

public KeyFactory(Class<KeyFormatProtoT> clazz)

Method Detail

getKeyFormatClass

public final Class<KeyFormatProtoT> getKeyFormatClass()

Returns the class corresponding to the key format protobuffer.

validateKeyFormat

public abstract void validateKeyFormat(KeyFormatProtoT keyFormatProto)
                                throws GeneralSecurityException

Checks if the given keyFormatProto is a valid key.

Throws:

GeneralSecurityException - if the passed keyFormatProto is not valid in any way.

parseKeyFormat

public abstract KeyFormatProtoT parseKeyFormat(com.google.protobuf.ByteString byteString)
                                        throws com.google.protobuf.InvalidProtocolBufferException

Parses a serialized key proto.

Implement as return KeyFormatProtoT.parseFrom(byteString);.

Throws:

com.google.protobuf.InvalidProtocolBufferException

createKey

public abstract KeyT createKey(KeyFormatProtoT keyFormat)
                        throws GeneralSecurityException

Creates a new key from a given format.

Throws:

GeneralSecurityException

deriveKey

public KeyT deriveKey(KeyFormatProtoT keyFormat,
                      InputStream pseudoRandomness)
               throws GeneralSecurityException

Derives a new key from a given format, using the given .

Implementations need to note that the given paramter may only produce a finite amount of randomness. Hence, proper implementations will first obtain all the pseudorandom bytes needed; and only after produce the key.

While validateKeyFormat is called before this method will be called, implementations must check the version of the given , as validateKeyFormat is also called from createKey.

Not every KeyTypeManager needs to implement this; if not implemented a GeneralSecurityException will be thrown.

Throws:

GeneralSecurityException