org.bouncycastle.crypto.hpke

Class HPKEContext

java.lang.Object

org.bouncycastle.crypto.hpke.HPKEContext

Direct Known Subclasses:

HPKEContextWithEncapsulation

public class HPKEContext
extends java.lang.Object

An HPKE encryption / decryption context produced by one of the HPKE.setup*R (recipient) factory methods, or — via the HPKEContextWithEncapsulation subclass — by one of the HPKE.setup*S (sender) factories.

The context is stateful: each seal(byte[], byte[]) / open(byte[], byte[]) call advances an internal sequence number that is XOR-mixed into the AEAD nonce per RFC 9180 §5.2, allowing a single context to encrypt or decrypt many messages in order without nonce reuse. export(byte[], int) derives auxiliary key material from the exporter secret and is deterministic — repeated calls with the same (exporterContext, L) return the same bytes.

Senders should use HPKEContextWithEncapsulation.getEncapsulation() to obtain the enc octet string that must be transmitted alongside the first ciphertext so the receiver can run the matching setup*R.

Field Summary

Fields

Modifier and Type	Field and Description
protected AEAD	aead
protected byte[]	exporterSecret
protected org.bouncycastle.crypto.hpke.HKDF	hkdf
protected byte[]	suiteId

Method Summary

Modifier and Type	Method and Description
byte[]	expand(byte[] prk, byte[] info, int L)
byte[]	export(byte[] exportContext, int L)
byte[]	extract(byte[] salt, byte[] ikm)
byte[]	open(byte[] aad, byte[] ct)
byte[]	open(byte[] aad, byte[] ct, int ctOffset, int ctLength)
byte[]	seal(byte[] aad, byte[] message)
byte[]	seal(byte[] aad, byte[] pt, int ptOffset, int ptLength)

Methods inherited from class java.lang.Object

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

Field Detail

aead

protected final AEAD aead

hkdf

protected final org.bouncycastle.crypto.hpke.HKDF hkdf

exporterSecret

protected final byte[] exporterSecret

suiteId

protected final byte[] suiteId

Method Detail

export

public byte[] export(byte[] exportContext,
                     int L)

seal

public byte[] seal(byte[] aad,
                   byte[] message)
            throws InvalidCipherTextException

Throws:

InvalidCipherTextException

seal

public byte[] seal(byte[] aad,
                   byte[] pt,
                   int ptOffset,
                   int ptLength)
            throws InvalidCipherTextException

Throws:

InvalidCipherTextException

open

public byte[] open(byte[] aad,
                   byte[] ct)
            throws InvalidCipherTextException

Throws:

InvalidCipherTextException

open

public byte[] open(byte[] aad,
                   byte[] ct,
                   int ctOffset,
                   int ctLength)
            throws InvalidCipherTextException

Throws:

InvalidCipherTextException

extract

public byte[] extract(byte[] salt,
                      byte[] ikm)

expand

public byte[] expand(byte[] prk,
                     byte[] info,
                     int L)