From f73aa1a2006beb741bc39026bfd10e6166d7951a Mon Sep 17 00:00:00 2001 From: Andreas Straub Date: Thu, 25 Jun 2015 16:56:34 +0200 Subject: Reworked axolotl protocol layer Numerous fixes --- .../crypto/axolotl/XmppAxolotlMessage.java | 180 +++++++++++++++++++++ 1 file changed, 180 insertions(+) (limited to 'src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java') diff --git a/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java b/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java index b11670e4..4b87fc5c 100644 --- a/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java +++ b/src/main/java/eu/siacs/conversations/crypto/axolotl/XmppAxolotlMessage.java @@ -1,4 +1,184 @@ package eu.siacs.conversations.crypto.axolotl; +import android.util.Base64; + +import java.security.InvalidAlgorithmParameterException; +import java.security.NoSuchAlgorithmException; +import java.security.InvalidKeyException; +import java.util.HashSet; +import java.util.Set; + +import javax.crypto.BadPaddingException; +import javax.crypto.Cipher; +import javax.crypto.IllegalBlockSizeException; +import javax.crypto.KeyGenerator; +import javax.crypto.NoSuchPaddingException; +import javax.crypto.SecretKey; +import javax.crypto.spec.IvParameterSpec; +import javax.crypto.spec.SecretKeySpec; + +import eu.siacs.conversations.entities.Contact; +import eu.siacs.conversations.xml.Element; + public class XmppAxolotlMessage { + private byte[] innerKey; + private byte[] ciphertext; + private byte[] iv; + private final Set headers; + private final Contact contact; + private final int sourceDeviceId; + + public static class XmppAxolotlMessageHeader { + private final int recipientDeviceId; + private final byte[] content; + + public XmppAxolotlMessageHeader(int deviceId, byte[] content) { + this.recipientDeviceId = deviceId; + this.content = content; + } + + public XmppAxolotlMessageHeader(Element header) { + if("header".equals(header.getName())) { + this.recipientDeviceId = Integer.parseInt(header.getAttribute("rid")); + this.content = Base64.decode(header.getContent(),Base64.DEFAULT); + } else { + throw new IllegalArgumentException("Argument not a
Element!"); + } + } + + public int getRecipientDeviceId() { + return recipientDeviceId; + } + + public byte[] getContents() { + return content; + } + + public Element toXml() { + Element headerElement = new Element("header"); + // TODO: generate XML + headerElement.setAttribute("rid", getRecipientDeviceId()); + headerElement.setContent(Base64.encodeToString(getContents(), Base64.DEFAULT)); + return headerElement; + } + } + + public static class XmppAxolotlPlaintextMessage { + private final AxolotlService.XmppAxolotlSession session; + private final String plaintext; + + public XmppAxolotlPlaintextMessage(AxolotlService.XmppAxolotlSession session, String plaintext) { + this.session = session; + this.plaintext = plaintext; + } + + public String getPlaintext() { + return plaintext; + } + } + + public XmppAxolotlMessage(Contact contact, Element axolotlMessage) { + this.contact = contact; + this.sourceDeviceId = Integer.parseInt(axolotlMessage.getAttribute("id")); + this.headers = new HashSet<>(); + for(Element child:axolotlMessage.getChildren()) { + switch(child.getName()) { + case "header": + headers.add(new XmppAxolotlMessageHeader(child)); + break; + case "message": + iv = Base64.decode(child.getAttribute("iv"),Base64.DEFAULT); + ciphertext = Base64.decode(child.getContent(),Base64.DEFAULT); + break; + default: + break; + } + } + } + + public XmppAxolotlMessage(Contact contact, int sourceDeviceId, String plaintext) { + this.contact = contact; + this.sourceDeviceId = sourceDeviceId; + this.headers = new HashSet<>(); + this.encrypt(plaintext); + } + + private void encrypt(String plaintext) { + try { + KeyGenerator generator = KeyGenerator.getInstance("AES"); + generator.init(128); + SecretKey secretKey = generator.generateKey(); + Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding"); + cipher.init(Cipher.ENCRYPT_MODE, secretKey); + this.innerKey = secretKey.getEncoded(); + this.iv = cipher.getIV(); + this.ciphertext = cipher.doFinal(plaintext.getBytes()); + } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException + | IllegalBlockSizeException | BadPaddingException e) { + + } + } + + public Contact getContact() { + return this.contact; + } + + public int getSenderDeviceId() { + return sourceDeviceId; + } + + public byte[] getCiphertext() { + return ciphertext; + } + + public Set getHeaders() { + return headers; + } + + public void addHeader(XmppAxolotlMessageHeader header) { + headers.add(header); + } + + public byte[] getInnerKey(){ + return innerKey; + } + + public byte[] getIV() { + return this.iv; + } + + public Element toXml() { + // TODO: generate outer XML, add in header XML + Element message= new Element("axolotl_message", AxolotlService.PEP_PREFIX); + message.setAttribute("id", sourceDeviceId); + for(XmppAxolotlMessageHeader header: headers) { + message.addChild(header.toXml()); + } + Element payload = message.addChild("message"); + payload.setAttribute("iv",Base64.encodeToString(iv, Base64.DEFAULT)); + payload.setContent(Base64.encodeToString(ciphertext,Base64.DEFAULT)); + return message; + } + + + public XmppAxolotlPlaintextMessage decrypt(AxolotlService.XmppAxolotlSession session, byte[] key) { + XmppAxolotlPlaintextMessage plaintextMessage = null; + try { + + Cipher cipher = Cipher.getInstance("AES/CTR/NoPadding"); + SecretKeySpec keySpec = new SecretKeySpec(key, "AES"); + IvParameterSpec ivSpec = new IvParameterSpec(iv); + + cipher.init(Cipher.DECRYPT_MODE, keySpec, ivSpec); + + String plaintext = new String(cipher.doFinal(ciphertext)); + plaintextMessage = new XmppAxolotlPlaintextMessage(session, plaintext); + + } catch (NoSuchAlgorithmException | NoSuchPaddingException | InvalidKeyException + | InvalidAlgorithmParameterException | IllegalBlockSizeException + | BadPaddingException e) { + throw new AssertionError(e); + } + return plaintextMessage; + } } -- cgit v1.2.3