net.i2p.router.transport.udp

Class SSU2Header

java.lang.Object

net.i2p.router.transport.udp.SSU2Header

final class SSU2Header
extends Object

Encrypt/decrypt headers

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	SSU2Header.Header A temporary structure returned from trial decrypt, with methods to access the fields.

Field Summary

Fields

Modifier and Type	Field and Description
static byte[]	CHACHA_IV_0 12 bytes of zeros
static byte[]	HEADER_PROT_DATA 8 bytes of zeros

Method Summary

Modifier and Type	Method and Description
static void	acceptTrialDecrypt(UDPPacket packet, SSU2Header.Header header) Copy the header back to the packet.
static long	decryptDestConnID(DatagramPacket pkt, byte[] key1) Decrypt bytes 0-7 in header.
static void	encryptHandshakeHeader(UDPPacket packet, byte[] key1, byte[] key2) First 64 bytes
static void	encryptLongHeader(UDPPacket packet, byte[] key1, byte[] key2) First 32 bytes
static void	encryptShortHeader(UDPPacket packet, byte[] key1, byte[] key2) First 16 bytes.
static SSU2Header.Header	trialDecryptHandshakeHeader(UDPPacket packet, byte[] key1, byte[] key2) Session Request and Session Created only.
static SSU2Header.Header	trialDecryptLongHeader(UDPPacket packet, byte[] key1, byte[] key2) Retry, Token Request, Peer Test only.
static SSU2Header.Header	trialDecryptShortHeader(UDPPacket packet, byte[] key1, byte[] key2) Session Confirmed and data phase.

Methods inherited from class java.lang.Object

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

Field Detail

CHACHA_IV_0

public static final byte[] CHACHA_IV_0

12 bytes of zeros

HEADER_PROT_DATA

public static final byte[] HEADER_PROT_DATA

8 bytes of zeros

Method Detail

acceptTrialDecrypt

public static void acceptTrialDecrypt(UDPPacket packet,
                                      SSU2Header.Header header)

Copy the header back to the packet. Cannot be undone.

decryptDestConnID

public static long decryptDestConnID(DatagramPacket pkt,
                                     byte[] key1)

Decrypt bytes 0-7 in header. Packet is unmodified.

Parameters:

pkt - must be 8 bytes min

Returns:

the destination connection ID

Throws:

IndexOutOfBoundsException - if too short

encryptHandshakeHeader

public static void encryptHandshakeHeader(UDPPacket packet,
                                          byte[] key1,
                                          byte[] key2)

First 64 bytes

encryptLongHeader

public static void encryptLongHeader(UDPPacket packet,
                                     byte[] key1,
                                     byte[] key2)

First 32 bytes

encryptShortHeader

public static void encryptShortHeader(UDPPacket packet,
                                      byte[] key1,
                                      byte[] key2)

First 16 bytes. First 8 bytes uses key1 and the next-to-last 12 bytes as the IV. Next 8 bytes uses key2 and the last 12 bytes as the IV.

trialDecryptHandshakeHeader

public static SSU2Header.Header trialDecryptHandshakeHeader(UDPPacket packet,
                                                            byte[] key1,
                                                            byte[] key2)

Session Request and Session Created only. 64 bytes. Packet is unmodified.

Parameters:

packet - must be 88 bytes min

Returns:

64 byte header, null if data too short

trialDecryptLongHeader

public static SSU2Header.Header trialDecryptLongHeader(UDPPacket packet,
                                                       byte[] key1,
                                                       byte[] key2)

Retry, Token Request, Peer Test only. 32 bytes. Packet is unmodified.

Parameters:

packet - must be 56 bytes min

Returns:

32 byte header, null if data too short

trialDecryptShortHeader

public static SSU2Header.Header trialDecryptShortHeader(UDPPacket packet,
                                                        byte[] key1,
                                                        byte[] key2)

Session Confirmed and data phase. 16 bytes. Packet is unmodified.

Parameters:

packet - must be 40 bytes min

Returns:

16 byte header, null if data too short, must be 40 bytes min