it.auties.whatsapp.crypto.Handshake Maven / Gradle / Ivy
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Standalone fully-featured Whatsapp Web API for Java and Kotlin
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package it.auties.whatsapp.crypto;
import it.auties.whatsapp.controller.Keys;
import it.auties.whatsapp.util.BytesHelper;
import it.auties.whatsapp.util.Spec;
import lombok.NonNull;
import java.util.Arrays;
public class Handshake {
private final Keys keys;
private byte[] hash;
private byte[] salt;
private byte[] cryptoKey;
private long counter;
public Handshake(Keys keys) {
this.keys = keys;
this.hash = Spec.Whatsapp.PROTOCOL;
this.salt = Spec.Whatsapp.PROTOCOL;
this.cryptoKey = Spec.Whatsapp.PROTOCOL;
this.counter = 0;
updateHash(keys.prologue());
}
public void updateHash(byte @NonNull [] data) {
var input = BytesHelper.concat(hash, data);
this.hash = Sha256.calculate(input);
}
public byte[] cipher(byte @NonNull [] bytes, boolean encrypt) {
var cyphered = encrypt ? AesGmc.encrypt(counter++, bytes, cryptoKey, hash) : AesGmc.decrypt(counter++, bytes, cryptoKey, hash);
if (!encrypt) {
updateHash(bytes);
return cyphered;
}
updateHash(cyphered);
return cyphered;
}
public void finish() {
var expanded = Hkdf.extractAndExpand(new byte[0], salt, null, 64);
keys.writeKey(Arrays.copyOfRange(expanded, 0, 32));
keys.readKey(Arrays.copyOfRange(expanded, 32, 64));
dispose();
}
private void dispose() {
this.hash = null;
this.salt = null;
this.cryptoKey = null;
this.counter = 0;
}
public void mixIntoKey(byte @NonNull [] bytes) {
var expanded = Hkdf.extractAndExpand(bytes, salt, null, 64);
this.salt = Arrays.copyOfRange(expanded, 0, 32);
this.cryptoKey = Arrays.copyOfRange(expanded, 32, 64);
this.counter = 0;
}
}