net.i2p.data.i2np

Class BuildRequestRecord

java.lang.Object

net.i2p.data.i2np.BuildRequestRecord

public class BuildRequestRecord
extends Object

As of 0.9.48, supports two formats. As of 0.9.51, supports three formats. The original 222-byte ElGamal format, the new 464-byte ECIES format, and the newest 154-byte ECIES format. See proposal 152 and 157 for details on the new formats. None of the readXXX() calls are cached. For efficiency, they should only be called once. Original ElGamal format: Holds the unencrypted 222-byte tunnel request record, with a constructor for ElGamal decryption and a method for ElGamal encryption. Iterative AES encryption/decryption is done elsewhere. Cleartext:

   bytes     0-3: tunnel ID to receive messages as
   bytes    4-35: local router identity hash (Unused and no accessor here)
   bytes   36-39: next tunnel ID
   bytes   40-71: next router identity hash
   bytes  72-103: AES-256 tunnel layer key
   bytes 104-135: AES-256 tunnel IV key
   bytes 136-167: AES-256 reply key
   bytes 168-183: reply IV
   byte      184: flags
   bytes 185-188: request time (in hours since the epoch)
   bytes 189-192: next message ID
   bytes 193-221: uninterpreted / random padding
 

Encrypted:

   bytes    0-15: First 16 bytes of router hash
   bytes  16-527: ElGamal encrypted block (discarding zero bytes at elg[0] and elg[257])
 

ECIES long record format, ref: proposal 152: Holds the unencrypted 464-byte tunnel request record, with a constructor for ECIES decryption and a method for ECIES encryption. Iterative AES encryption/decryption is done elsewhere. Cleartext:

   bytes     0-3: tunnel ID to receive messages as, nonzero
   bytes     4-7: next tunnel ID, nonzero
   bytes    8-39: next router identity hash
   bytes   40-71: AES-256 tunnel layer key
   bytes  72-103: AES-256 tunnel IV key
   bytes 104-135: AES-256 reply key
   bytes 136-151: AES-256 reply IV
   byte      152: flags
   bytes 153-155: more flags, unused, set to 0 for compatibility
   bytes 156-159: request time (in minutes since the epoch, rounded down)
   bytes 160-163: request expiration (in seconds since creation)
   bytes 164-167: next message ID
   bytes   168-x: tunnel build options (Mapping)
   bytes     x-x: other data as implied by flags or options
   bytes   x-463: random padding
 

Encrypted:

   bytes    0-15: Hop's truncated identity hash
   bytes   16-47: Sender's ephemeral X25519 public key
   bytes  48-511: ChaCha20 encrypted BuildRequestRecord
   bytes 512-527: Poly1305 MAC
 

ECIES short record format, ref: proposal 157: Holds the unencrypted 154-byte tunnel request record, with a constructor for ECIES decryption and a method for ECIES encryption. Iterative AES encryption/decryption is done elsewhere. Cleartext:

   bytes     0-3: tunnel ID to receive messages as, nonzero
   bytes     4-7: next tunnel ID, nonzero
   bytes    8-39: next router identity hash
   byte       40: flags
   bytes   41-42: more flags, unused, set to 0 for compatibility
   byte       43: layer enc. type
   bytes   44-47: request time (in minutes since the epoch, rounded down)
   bytes   48-51: request expiration (in seconds since creation)
   bytes   52-55: next message ID
   bytes    56-x: tunnel build options (Mapping)
   bytes     x-x: other data as implied by flags or options
   bytes   x-153: random padding
 

Encrypted:

   bytes    0-15: Hop's truncated identity hash
   bytes   16-47: Sender's ephemeral X25519 public key
   bytes  48-201: ChaCha20 encrypted BuildRequestRecord
   bytes 202-217: Poly1305 MAC
 

Field Summary

Fields

Modifier and Type	Field and Description
static int	IV_SIZE IV size in bytes
static int	OFF_REPLY_KEY Offset for reply key in ElGamal format
static int	OFF_REPLY_KEY_EC Offset for reply key in ECIES long format
static int	PEER_SIZE we show 16 bytes of the peer hash outside the elGamal block

Constructor Summary

Constructors

Constructor and Description
BuildRequestRecord(I2PAppContext ctx, long receiveTunnelId, Hash peer, long nextTunnelId, Hash nextHop, long nextMsgId, SessionKey layerKey, SessionKey ivKey, SessionKey replyKey, byte[] iv, boolean isInGateway, boolean isOutEndpoint) Creates a new ElGamal build request record.
BuildRequestRecord(I2PAppContext ctx, long receiveTunnelId, long nextTunnelId, Hash nextHop, long nextMsgId, boolean isInGateway, boolean isOutEndpoint, Properties options) Creates a new ECIES short build request record.
BuildRequestRecord(I2PAppContext ctx, long receiveTunnelId, long nextTunnelId, Hash nextHop, long nextMsgId, SessionKey layerKey, SessionKey ivKey, SessionKey replyKey, byte[] iv, boolean isInGateway, boolean isOutEndpoint, Properties options) Creates a new ECIES long build request record.
BuildRequestRecord(RouterContext ctx, PrivateKey ourKey, EncryptedBuildRecord encryptedRecord) Decrypts an encrypted build request record.

Method Summary

Modifier and Type	Method and Description
EncryptedBuildRecord	encryptECIESRecord(RouterContext ctx, PublicKey toKey, Hash toPeer) Encrypts the record using ECIES.
EncryptedBuildRecord	encryptRecord(I2PAppContext ctx, PublicKey toKey, Hash toPeer) Encrypts the record using ElGamal.
byte[]	getChaChaReplyAD() Returns the ChaCha reply AD (Associated Data).
SessionKey	getChaChaReplyKey() Returns the ChaCha reply key.
byte[]	getData() Returns the raw record data.
long	readExpiration() Reads the expiration time.
MessageWrapper.OneTimeSession	readGarlicKeys() Reads the garlic keys for OBEP.
boolean	readIsInboundGateway() Reads whether this hop is an inbound gateway.
boolean	readIsOutboundEndpoint() Reads whether this hop is an outbound endpoint.
SessionKey	readIVKey() Reads the tunnel IV encryption key.
int	readLayerEncryptionType() Reads the layer encryption type.
SessionKey	readLayerKey() Reads the tunnel layer encryption key.
Hash	readNextIdentity() Reads the next hop's identity hash.
long	readNextTunnelId() Reads the next hop's tunnel ID.
Properties	readOptions() Reads the tunnel build options.
long	readReceiveTunnelId() Reads the tunnel ID this hop should receive messages on.
byte[]	readReplyIV() Reads the reply IV.
SessionKey	readReplyKey() Reads the reply encryption key.
long	readReplyMessageId() Reads the reply message ID.
long	readRequestTime() Reads the request time.
String	toString() Returns a string representation of this record.

Methods inherited from class java.lang.Object

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

Field Detail

IV_SIZE

public static final int IV_SIZE

IV size in bytes

See Also:

Constant Field Values

OFF_REPLY_KEY

public static final int OFF_REPLY_KEY

Offset for reply key in ElGamal format

See Also:

Constant Field Values

OFF_REPLY_KEY_EC

public static final int OFF_REPLY_KEY_EC

Offset for reply key in ECIES long format

See Also:

Constant Field Values

PEER_SIZE

public static final int PEER_SIZE

we show 16 bytes of the peer hash outside the elGamal block

See Also:

Constant Field Values

Constructor Detail

BuildRequestRecord

public BuildRequestRecord(I2PAppContext ctx,
                          long receiveTunnelId,
                          Hash peer,
                          long nextTunnelId,
                          Hash nextHop,
                          long nextMsgId,
                          SessionKey layerKey,
                          SessionKey ivKey,
                          SessionKey replyKey,
                          byte[] iv,
                          boolean isInGateway,
                          boolean isOutEndpoint)

Creates a new ElGamal build request record. Populate this instance with data. A new buffer is created to contain the data, with the necessary randomized padding. ElGamal only. ECIES constructor below.

Parameters:

ctx - the application context

receiveTunnelId - tunnel the current hop will receive messages on

peer - current hop's identity, unused, no read() method

nextTunnelId - id for the next hop, or where we send the reply (if we are the outbound endpoint)

nextHop - next hop's identity, or where we send the reply (if we are the outbound endpoint)

nextMsgId - message ID to use when sending on to the next hop (or for the reply)

layerKey - tunnel layer key to be used by the peer

ivKey - tunnel IV key to be used by the peer

replyKey - key to be used when encrypting the reply to this build request

iv - iv to be used when encrypting the reply to this build request

isInGateway - are we the gateway of an inbound tunnel?

isOutEndpoint - are we the endpoint of an outbound tunnel?

BuildRequestRecord

public BuildRequestRecord(I2PAppContext ctx,
                          long receiveTunnelId,
                          long nextTunnelId,
                          Hash nextHop,
                          long nextMsgId,
                          boolean isInGateway,
                          boolean isOutEndpoint,
                          Properties options)

Creates a new ECIES short build request record. Populate this instance with data. A new buffer is created to contain the data, with the necessary randomized padding. ECIES short record only. ElGamal constructor above.

Parameters:

ctx - the application context

receiveTunnelId - tunnel the current hop will receive messages on

nextTunnelId - id for the next hop, or where we send the reply (if we are the outbound endpoint)

nextHop - next hop's identity, or where we send the reply (if we are the outbound endpoint)

nextMsgId - message ID to use when sending on to the next hop (or for the reply)

isInGateway - are we the gateway of an inbound tunnel?

isOutEndpoint - are we the endpoint of an outbound tunnel?

options - 98 bytes max when serialized

Throws:

IllegalArgumentException - if options too long

BuildRequestRecord

public BuildRequestRecord(I2PAppContext ctx,
                          long receiveTunnelId,
                          long nextTunnelId,
                          Hash nextHop,
                          long nextMsgId,
                          SessionKey layerKey,
                          SessionKey ivKey,
                          SessionKey replyKey,
                          byte[] iv,
                          boolean isInGateway,
                          boolean isOutEndpoint,
                          Properties options)

Creates a new ECIES long build request record. Populate this instance with data. A new buffer is created to contain the data, with the necessary randomized padding. ECIES long record only. ElGamal constructor above.

Parameters:

ctx - the application context

receiveTunnelId - tunnel the current hop will receive messages on

nextTunnelId - id for the next hop, or where we send the reply (if we are the outbound endpoint)

nextHop - next hop's identity, or where we send the reply (if we are the outbound endpoint)

nextMsgId - message ID to use when sending on to the next hop (or for the reply)

layerKey - tunnel layer key to be used by the peer

ivKey - tunnel IV key to be used by the peer

replyKey - key to be used when encrypting the reply to this build request

iv - iv to be used when encrypting the reply to this build request

isInGateway - are we the gateway of an inbound tunnel?

isOutEndpoint - are we the endpoint of an outbound tunnel?

options - 296 bytes max when serialized

Throws:

IllegalArgumentException - if options too long

BuildRequestRecord

public BuildRequestRecord(RouterContext ctx,
                          PrivateKey ourKey,
                          EncryptedBuildRecord encryptedRecord)
                   throws DataFormatException

Decrypts an encrypted build request record. Decrypt the data from the specified record, writing the decrypted record into this instance's data buffer Caller MUST check that first 16 bytes of our hash matches first 16 bytes of encryptedRecord before calling this. Not checked here. The ChaCha reply key and IV will be available via the getters after this call if ourKey is ECIES.

Parameters:

ctx - the router context

ourKey - our private key to decrypt with

encryptedRecord - the encrypted build record

Throws:

DataFormatException - on decrypt fail

Method Detail

encryptECIESRecord

public EncryptedBuildRecord encryptECIESRecord(RouterContext ctx,
                                               PublicKey toKey,
                                               Hash toPeer)

Encrypts the record using ECIES. Encrypt the record to the specified peer. ECIES only. The ChaCha reply key and IV will be available via the getters after this call. For short records, derived keys will be available via readLayerKey(), readIVKey(), and readGarlicKeys() after this call. See class javadocs for format. See proposals 152 and 157.

Parameters:

ctx - the router context

toKey - the public key to encrypt to

toPeer - the peer's identity hash

Returns:

the encrypted build record, non-null

Throws:

IllegalArgumentException - if key type is not ECIES

IllegalStateException - on encryption failure

encryptRecord

public EncryptedBuildRecord encryptRecord(I2PAppContext ctx,
                                          PublicKey toKey,
                                          Hash toPeer)

Encrypts the record using ElGamal. Encrypt the record to the specified peer. The result is formatted as:

   bytes 0-15: truncated SHA-256 of the current hop's identity (the toPeer parameter)
 bytes 15-527: ElGamal-2048 encrypted block
 

ElGamal only.

Parameters:

ctx - the application context

toKey - the public key to encrypt to

toPeer - the peer's identity hash

Returns:

the encrypted build record, non-null

Throws:

IllegalArgumentException - if key type is not ElGamal

getChaChaReplyAD

public byte[] getChaChaReplyAD()

Returns the ChaCha reply AD (Associated Data). Valid after calling encryptECIESRecord() or after the decrypting constructor with an ECIES private key. See proposal 152.

Returns:

the AD data (32 bytes), or null if no ECIES encrypt/decrypt operation was performed

getChaChaReplyKey

public SessionKey getChaChaReplyKey()

Returns the ChaCha reply key. Valid after calling encryptECIESRecord() or after the decrypting constructor with an ECIES private key. See proposal 152.

Returns:

the session key, or null if no ECIES encrypt/decrypt operation was performed

getData

public byte[] getData()

Returns the raw record data.

Returns:

222 (ElG) or 464 (ECIES) bytes, non-null

readExpiration

public long readExpiration()

Reads the expiration time. The expiration in milliseconds from now.

Returns:

the expiration in milliseconds

readGarlicKeys

public MessageWrapper.OneTimeSession readGarlicKeys()

Reads the garlic keys for OBEP. ECIES short OBEP record only.

Returns:

the garlic keys, or null for ElGamal or ECIES long record or non-OBEP

readIsInboundGateway

public boolean readIsInboundGateway()

Reads whether this hop is an inbound gateway. The current hop is the inbound gateway. If this is true, it means anyone can send messages to this tunnel, but if it is false, only the current predecessor can.

Returns:

true if inbound gateway, false otherwise

readIsOutboundEndpoint

public boolean readIsOutboundEndpoint()

Reads whether this hop is an outbound endpoint. The current hop is the outbound endpoint. If this is true, the next identity and next tunnel fields refer to where the reply should be sent.

Returns:

true if outbound endpoint, false otherwise

readIVKey

public SessionKey readIVKey()

Reads the tunnel IV encryption key. Tunnel IV encryption key that the current hop should use

Returns:

the session key for IV encryption

readLayerEncryptionType

public int readLayerEncryptionType()

Reads the layer encryption type. ECIES short record only.

Returns:

the encryption type (0-255), or 0 for ElGamal or ECIES long record

readLayerKey

public SessionKey readLayerKey()

Reads the tunnel layer encryption key. Tunnel layer encryption key that the current hop should use

Returns:

the session key for layer encryption

readNextIdentity

public Hash readNextIdentity()

Reads the next hop's identity hash. Read the next hop from the record. If this is the outbound tunnel endpoint, this specifies the gateway to which the reply should be sent.

Returns:

the next hop's identity hash, non-null

readNextTunnelId

public long readNextTunnelId()

Reads the next hop's tunnel ID. What tunnel ID the next hop receives messages on. If this is the outbound tunnel endpoint, this specifies the tunnel ID to which the reply should be sent.

Returns:

the next tunnel ID

readOptions

public Properties readOptions()

Reads the tunnel build options. ECIES only.

Returns:

the properties, or null for ElGamal or on error

readReceiveTunnelId

public long readReceiveTunnelId()

Reads the tunnel ID this hop should receive messages on.

Returns:

the tunnel ID

readReplyIV

public byte[] readReplyIV()

Reads the reply IV. AES IV that should be used to encrypt the reply. Not to be used for short ECIES records.

Returns:

16 bytes IV data

Throws:

IllegalStateException - for short ECIES records

readReplyKey

public SessionKey readReplyKey()

Reads the reply encryption key. AES Session key that should be used to encrypt the reply. Not to be used for short ECIES records; use the ChaChaReplyKey instead.

Returns:

the session key for reply encryption

Throws:

IllegalStateException - for short ECIES records

readReplyMessageId

public long readReplyMessageId()

Reads the reply message ID. What message ID should we send the request to the next hop with. If this is the outbound tunnel endpoint, this specifies the message ID with which the reply should be sent.

Returns:

the reply message ID

readRequestTime

public long readRequestTime()

Reads the request time. For ElGamal, time that the request was sent (ms), truncated to the nearest hour. For ECIES, time that the request was sent (ms), truncated to the nearest minute. This ignores leap seconds.

Returns:

the request time in milliseconds

toString

public String toString()

Returns a string representation of this record.

Overrides:

toString in class Object

Returns:

a string representation