com.google.crypto.tink.hybrid.HpkeParameters Maven / Gradle / Ivy
Show all versions of tink-android Show documentation
// Copyright 2023 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
////////////////////////////////////////////////////////////////////////////////
package com.google.crypto.tink.hybrid;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import com.google.errorprone.annotations.Immutable;
import java.security.GeneralSecurityException;
import java.util.Objects;
/** Description of the parameters for an {@link HpkePublicKey} or {@link HpkePrivateKey}. */
public final class HpkeParameters extends HybridParameters {
/** Description of the output prefix prepended to the ciphertext. */
@Immutable
public static final class Variant {
/** {@code TINK}: Leading 0x01-byte followed by 4-byte key id (big endian format). */
public static final Variant TINK = new Variant("TINK");
/** {@code CRUNCHY}: Leading 0x00-byte followed by 4-byte key id (big endian format). */
public static final Variant CRUNCHY = new Variant("CRUNCHY");
/** {@code NO_PREFIX}: Empty prefix. */
public static final Variant NO_PREFIX = new Variant("NO_PREFIX");
private final String name;
private Variant(String name) {
this.name = name;
}
@Override
public String toString() {
return name;
}
}
/**
* HPKE algorithm identifiers.
*
* See https://www.rfc-editor.org/rfc/rfc9180.html#section-7.
*/
@Immutable
private static class AlgorithmIdentifier {
protected final String name;
protected final int value;
private AlgorithmIdentifier(String name, int value) {
this.name = name;
this.value = value;
}
public int getValue() {
return value;
}
@Override
public String toString() {
return String.format("%s(0x%04x)", name, value);
}
}
/**
* HPKE KEM identifiers.
*
*
See https://www.rfc-editor.org/rfc/rfc9180.html#section-7.1.
*/
@Immutable
public static final class KemId extends AlgorithmIdentifier {
public static final KemId DHKEM_P256_HKDF_SHA256 = new KemId("DHKEM_P256_HKDF_SHA256", 0x10);
public static final KemId DHKEM_P384_HKDF_SHA384 = new KemId("DHKEM_P384_HKDF_SHA384", 0x11);
public static final KemId DHKEM_P521_HKDF_SHA512 = new KemId("DHKEM_P521_HKDF_SHA512", 0x12);
public static final KemId DHKEM_X25519_HKDF_SHA256 =
new KemId("DHKEM_X25519_HKDF_SHA256", 0x20);
private KemId(String name, int value) {
super(name, value);
}
}
/**
* HPKE KDF identifiers.
*
*
See https://www.rfc-editor.org/rfc/rfc9180.html#section-7.2.
*/
@Immutable
public static final class KdfId extends AlgorithmIdentifier {
public static final KdfId HKDF_SHA256 = new KdfId("HKDF_SHA256", 0x01);
public static final KdfId HKDF_SHA384 = new KdfId("HKDF_SHA384", 0x02);
public static final KdfId HKDF_SHA512 = new KdfId("HKDF_SHA512", 0x03);
private KdfId(String name, int value) {
super(name, value);
}
}
/**
* HPKE AEAD identifiers.
*
*
See https://www.rfc-editor.org/rfc/rfc9180.html#section-7.3.
*/
@Immutable
public static final class AeadId extends AlgorithmIdentifier {
public static final AeadId AES_128_GCM = new AeadId("AES_128_GCM", 0x01);
public static final AeadId AES_256_GCM = new AeadId("AES_256_GCM", 0x02);
public static final AeadId CHACHA20_POLY1305 = new AeadId("CHACHA20_POLY1305", 0x03);
private AeadId(String name, int value) {
super(name, value);
}
}
/** Builds a new {@link HpkeParameters} instance. */
public static final class Builder {
private KemId kem = null;
private KdfId kdf = null;
private AeadId aead = null;
private Variant variant = Variant.NO_PREFIX;
private Builder() {}
@CanIgnoreReturnValue
public Builder setKemId(KemId kem) {
this.kem = kem;
return this;
}
@CanIgnoreReturnValue
public Builder setKdfId(KdfId kdf) {
this.kdf = kdf;
return this;
}
@CanIgnoreReturnValue
public Builder setAeadId(AeadId aead) {
this.aead = aead;
return this;
}
@CanIgnoreReturnValue
public Builder setVariant(Variant variant) {
this.variant = variant;
return this;
}
public HpkeParameters build() throws GeneralSecurityException {
if (kem == null) {
throw new GeneralSecurityException("HPKE KEM parameter is not set");
}
if (kdf == null) {
throw new GeneralSecurityException("HPKE KDF parameter is not set");
}
if (aead == null) {
throw new GeneralSecurityException("HPKE AEAD parameter is not set");
}
if (variant == null) {
throw new GeneralSecurityException("HPKE variant is not set");
}
return new HpkeParameters(kem, kdf, aead, variant);
}
}
private final KemId kem;
private final KdfId kdf;
private final AeadId aead;
private final Variant variant;
private HpkeParameters(KemId kem, KdfId kdf, AeadId aead, Variant variant) {
this.kem = kem;
this.kdf = kdf;
this.aead = aead;
this.variant = variant;
}
public static Builder builder() {
return new Builder();
}
public KemId getKemId() {
return kem;
}
public KdfId getKdfId() {
return kdf;
}
public AeadId getAeadId() {
return aead;
}
public Variant getVariant() {
return variant;
}
@Override
public boolean hasIdRequirement() {
return variant != Variant.NO_PREFIX;
}
@Override
public boolean equals(Object o) {
if (!(o instanceof HpkeParameters)) {
return false;
}
HpkeParameters other = (HpkeParameters) o;
return kem == other.kem && kdf == other.kdf && aead == other.aead && variant == other.variant;
}
@Override
public int hashCode() {
return Objects.hash(HpkeParameters.class, kem, kdf, aead, variant);
}
}