com.google.crypto.tink.hybrid

Class EciesParameters

java.lang.Object

com.google.crypto.tink.Parameters

com.google.crypto.tink.hybrid.HybridParameters

com.google.crypto.tink.hybrid.EciesParameters

public final class EciesParameters
extends HybridParameters

Parameters for an ECIES primitive with HKDF and AEAD encryption.

This API follows loosely ECIES ISO 18033-2 standard (Elliptic Curve Integrated Encryption Scheme, see http://www.shoup.net/iso/std6.pdf), but with some differences:

• use of HKDF key derivation function (instead of KDF1 and KDF2) enabling the use of optional parameters to the key derivation function, which strenghten the overall security and allow for binding the key material to application-specific information (see RFC 5869)
• use of modern AEAD/Deterministic AEAD schemes rather than "manual composition" of symmetric encryption with message authentication codes (as in DEM1, DEM2, and DEM3 schemes of ISO 18033-2)

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	EciesParameters.Builder Builds a new EciesParameters instance.
static class	EciesParameters.CurveType The elliptic curve type used for the KEM.
static class	EciesParameters.HashType The Hash algorithm used for the KEM.
static class	EciesParameters.PointFormat The Elliptic Curve Point Format.
static class	EciesParameters.Variant Description of the output prefix prepended to the ciphertext.

Method Summary

Modifier and Type	Method and Description
static EciesParameters.Builder	builder()
boolean	equals(Object o)
EciesParameters.CurveType	getCurveType()
Parameters	getDemParameters()
EciesParameters.HashType	getHashType()
EciesParameters.PointFormat	getNistCurvePointFormat()
Bytes	getSalt() Gets the salt value, which defaults to null if not set.
EciesParameters.Variant	getVariant()
int	hashCode()
boolean	hasIdRequirement() Returns true if a key created with the parameters in this object has to have a certain ID when it is in a keyset.
String	toString()

Methods inherited from class java.lang.Object

clone, finalize, getClass, notify, notifyAll, wait, wait, wait

Method Detail

builder

public static EciesParameters.Builder builder()

getCurveType

public EciesParameters.CurveType getCurveType()

getHashType

public EciesParameters.HashType getHashType()

getNistCurvePointFormat

@Nullable
public EciesParameters.PointFormat getNistCurvePointFormat()

getDemParameters

public Parameters getDemParameters()

getVariant

public EciesParameters.Variant getVariant()

getSalt

@Nullable
public Bytes getSalt()

Gets the salt value, which defaults to null if not set.

This class does not store an RFC compliant default value and the converion must be done in the implementation (meaning that a null salt must be converted to a string of zeros that is of the length of the hash function output, as per RFC 5869).

hasIdRequirement

public boolean hasIdRequirement()

Description copied from class: Parameters

Returns true if a key created with the parameters in this object has to have a certain ID when it is in a keyset.

In Tink, certain keys change their behavior depending on the key id (for example, an Aead object can prefix the ciphertext with the big endian encoding of the key id). If this is the case, such a key should require a unique id in Key.getIdRequirementOrNull() and return true here.

Specified by:

hasIdRequirement in class Parameters

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object

toString

public String toString()

Overrides:

toString in class Object