Package com.google.crypto.tink.hybrid

Class EciesPublicKey

java.lang.Object

com.google.crypto.tink.Key

com.google.crypto.tink.hybrid.HybridPublicKey

com.google.crypto.tink.hybrid.EciesPublicKey

@Immutable
public final class EciesPublicKey
extends HybridPublicKey

Represents the encryption function for an ECIES hybrid encryption primitive.

Method Summary

Modifier and Type	Method	Description
static EciesPublicKey	createForCurveX25519(EciesParameters parameters, Bytes publicPointBytes, java.lang.Integer idRequirement)	Creates a new ECIES public key using Curve25519.
static EciesPublicKey	createForNistCurve(EciesParameters parameters, java.security.spec.ECPoint publicPoint, java.lang.Integer idRequirement)	Creates a new ECIES public key using a NIST Curve.
boolean	equalsKey(Key o)	Returns true if the key is guaranteed to be equal to other.
java.lang.Integer	getIdRequirementOrNull()	Returns null if this key has no id requirement, otherwise the required id.
java.security.spec.ECPoint	getNistCurvePoint()	Returns the underlying public point if the curve is a NIST curve.
Bytes	getOutputPrefix()	Returns a Bytes instance, which is prefixed to every ciphertext.
EciesParameters	getParameters()	Returns a Parameters object containing all the information about the key which is not randomly chosen.
Bytes	getX25519CurvePointBytes()	Returns the underlying public point as EC Point in case the curve is a NIST curve.

Methods inherited from class java.lang.Object

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

Method Detail

createForCurveX25519

public static EciesPublicKey createForCurveX25519(EciesParameters parameters,
                                                  Bytes publicPointBytes,
                                                  @Nullable
                                                  java.lang.Integer idRequirement)
                                           throws java.security.GeneralSecurityException

Creates a new ECIES public key using Curve25519.

Parameters:

parameters - ECIES parameters for the public key

publicPointBytes - public point coordinates in bytes.

idRequirement - key id requirement, which must be null for NO_PREFIX variant and non-null for all other variants

Throws:

java.security.GeneralSecurityException

createForNistCurve

public static EciesPublicKey createForNistCurve(EciesParameters parameters,
                                                java.security.spec.ECPoint publicPoint,
                                                @Nullable
                                                java.lang.Integer idRequirement)
                                         throws java.security.GeneralSecurityException

Creates a new ECIES public key using a NIST Curve.

Parameters:

parameters - ECIES parameters for the public key

publicPoint - public point as a ECPoint.

idRequirement - key id requirement, which must be null for NO_PREFIX variant and non-null for all other variants

Throws:

java.security.GeneralSecurityException

getNistCurvePoint

@Nullable
public java.security.spec.ECPoint getNistCurvePoint()

Returns the underlying public point if the curve is a NIST curve.

Returns null if the curve used for this key is not a NIST curve.

getX25519CurvePointBytes

@Nullable
public Bytes getX25519CurvePointBytes()

Returns the underlying public point as EC Point in case the curve is a NIST curve.

Returns null for X25519 curves.

getOutputPrefix

public Bytes getOutputPrefix()

Description copied from class: HybridPublicKey

Returns a Bytes instance, which is prefixed to every ciphertext.

Specified by:

getOutputPrefix in class HybridPublicKey

getParameters

public EciesParameters getParameters()

Description copied from class: Key

Returns a Parameters object containing all the information about the key which is not randomly chosen.

Implementations need to ensure that getParameters().hasIdRequirement() returns true if and only if getIdRequirementOrNull is non-null.

Specified by:

getParameters in class HybridPublicKey

getIdRequirementOrNull

@Nullable
public java.lang.Integer getIdRequirementOrNull()

Description copied from class: Key

Returns null if this key has no id requirement, otherwise the required id.

Some keys, when they are in a keyset, are required to have a certain ID to work properly. This comes from the fact that Tink in some cases prefixes ciphertexts or signatures with the string 0x01<id>, where the ID is encoded in big endian (see the documentation of the key type for details), in which case the key requires a certain ID.

Specified by:

getIdRequirementOrNull in class Key

equalsKey

public boolean equalsKey(Key o)

Description copied from class: Key

Returns true if the key is guaranteed to be equal to other.

Implementations are required to do this in constant time.

Note: this is allowed to return false even if two keys are guaranteed to represent the same function, but are represented differently. For example, a key is allowed to internally store the number of zero-bytes used as padding when a large number is represented as a byte array, and use this in the comparison.

Note: Tink Key objects should typically not override hashCode (because it could risk leaking key material). Hence, they typically also should not override equals.

Specified by:

equalsKey in class Key