Class EstablishedEcies

java.lang.Object

io.github.fherbreteau.vodozemac.NativeHandle

io.github.fherbreteau.vodozemac.ecies.EstablishedEcies

All Implemented Interfaces:

AutoCloseable

public final class EstablishedEcies
extends NativeHandle

An established ECIES channel that can be used to encrypt and decrypt messages between the two sides of the channel.

An EstablishedEcies is obtained by calling Ecies.establishOutboundChannel(String, byte[]) on the initiator side or Ecies.establishInboundChannel(String) on the recipient side. Once established, it can be used to:

• Encrypt and decrypt messages using ChaCha20-Poly1305 via encrypt(byte[]) and decrypt(String)
• Retrieve the CheckCode for out-of-band MITM verification via checkCode()
• Retrieve the Curve25519 public key via publicKey()

The encryption and decryption operations use internal nonce counters that increment with each message. Messages must be decrypted in the same order they were encrypted.

This class implements AutoCloseable and should be used in a try-with-resources block to ensure native resources are properly released.

Author:

François HERBRETEAU

Method Summary

Modifier and Type	Method	Description
CheckCode	checkCode()	Returns the CheckCode which uniquely identifies this ECIES session.
byte[]	decrypt(String message)	Decrypts the given message using this ECIES session.
String	encrypt(byte[] plaintext)	Encrypts the given plaintext using this ECIES session.
boolean	equals(Object o)
int	hashCode()
String	publicKey()	Returns our Curve25519 public key that was used to establish the ECIES channel.

Methods inherited from class NativeHandle

checkNotClosed, close, invalidate, nativePtr

Methods inherited from class Object

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

Method Details

publicKey

public String publicKey()

Returns our Curve25519 public key that was used to establish the ECIES channel.

Returns:

the base64-encoded public key

Throws:

IllegalStateException - if this EstablishedEcies has been closed

checkCode

public CheckCode checkCode()

Returns the CheckCode which uniquely identifies this ECIES session.

The check code can be used to verify that both sides of the session are using the same shared secret. It should be shared out-of-band to protect against active man-in-the-middle (MITM) attacks.

Returns:

the check code

Throws:

IllegalStateException - if this EstablishedEcies has been closed

encrypt

public String encrypt(byte[] plaintext)

Encrypts the given plaintext using this ECIES session.

The ciphertext is returned as a base64-encoded string. Each call to this method uses an incrementing nonce, so messages must be decrypted in the same order they were encrypted.

Parameters:

plaintext - the plaintext to encrypt

Returns:

the encrypted message as a base64-encoded string

Throws:

IllegalStateException - if this EstablishedEcies has been closed

decrypt

public byte[] decrypt(String message)

Decrypts the given message using this ECIES session.

The message must be a base64-encoded string produced by encrypt(byte[]) on the other side. Each call to this method uses an incrementing nonce, so messages must be decrypted in the same order they were encrypted by the sender.

Parameters:

message - the encrypted message as a base64-encoded string

Returns:

the decrypted plaintext

Throws:

IllegalStateException - if this EstablishedEcies has been closed

EciesException - if decryption fails, e.g. due to a corrupted message, a replayed message, or a key mismatch

equals

public boolean equals(Object o)

Overrides:

equals in class Object

hashCode

public int hashCode()

Overrides:

hashCode in class Object