SSU2Util (Javadocs [I2P+ 2.13.0+] - API Version 0.9.70+)

java.lang.Object
- net.i2p.router.transport.udp.SSU2Util

```
final class SSU2Util
extends Object
```
SSU2 Utils and constants

Field Summary

Fields
Modifier and Type	Field and Description
`static int`	`CHACHA_IV_LEN` 12 bytes, ChaCha20 nonce length
`static byte`	`DATA_FLAG_BYTE` Message type flag for data
`static int`	`DATA_FOLLOWON_EXTRA_SIZE` 5 for flag and msg number in followon block
`static int`	`DATA_HEADER_SIZE` 16 byte short header
`static int`	`DEST_CONN_ID_OFFSET` Offset of destination connection ID in header
`static int`	`FIRST_FRAGMENT_HEADER_SIZE` 3 byte block header
`static int`	`FOLLOWON_FRAGMENT_HEADER_SIZE` 3 byte block header + 4 byte msg ID + 1 byte fragment info = 8
`static int`	`HEADER_PROT_1_OFFSET` Offset of first header protection region (dest conn ID)
`static int`	`HEADER_PROT_2_OFFSET` Offset of second header protection region (packet number)
`static int`	`HEADER_PROT_DATA_LEN` Length of header protection data in bytes
`static int`	`HEADER_PROT_SAMPLE_1_OFFSET` Offset of first header protection sample
`static int`	`HEADER_PROT_SAMPLE_2_OFFSET` Offset of second header protection sample
`static int`	`HEADER_PROT_SAMPLE_LEN` Length of header protection sample in bytes
`static byte`	`HOLE_PUNCH_FLAG_BYTE` Message type flag for hole punch
`static String`	`INFO_CONFIRMED` HKDF info string for session confirmed key derivation
`static String`	`INFO_CREATED` HKDF info string for session created header key derivation
`static String`	`INFO_DATA` HKDF info string for data packet key derivation
`static int`	`INTRO_KEY_LEN` 32 bytes, introductory key length
`static int`	`KEY_LEN` 32 bytes, X25519 public key length
`static int`	`LONG_HEADER_FLAGS_OFFSET` Offset of long header flags
`static int`	`LONG_HEADER_SIZE` 32 bytes, long (handshake) header size
`static int`	`MAC_LEN` 16 bytes, MAC tag length
`static int`	`MIN_DATA_LEN` Short message type (e.g.
`static int`	`MIN_HANDSHAKE_DATA_LEN` Handshake message type minimum length in bytes (88).
`static int`	`MIN_LONG_DATA_LEN` Long message type minimum length in bytes (56).
`static int`	`MIN_RETRY_LEN` Retry message minimum length in bytes (56).
`static int`	`MIN_SESSION_CREATED_LEN` Session created minimum length in bytes (88).
`static int`	`MIN_SESSION_REQUEST_LEN` Session request minimum length in bytes (88).
`static int`	`MIN_TOKEN_REQUEST_LEN` Token request minimum length in bytes (56).
`static int`	`NETID_OFFSET` Offset of network ID in header
`static int`	`PADDING_MAX` Maximum padding for data packets
`static int`	`PADDING_MAX_SESSION_CREATED` Maximum padding for session created
`static int`	`PADDING_MAX_SESSION_REQUEST` Maximum padding for session request
`static byte`	`PEER_TEST_FLAG_BYTE` Message type flag for peer test
`static byte[]`	`PEER_TEST_PROLOGUE` Prologue for peer test signatures
`static int`	`PKT_NUM_LEN` Length of packet number field in bytes
`static int`	`PKT_NUM_OFFSET` Offset of packet number in header
`static int`	`PROTOCOL_VERSION` SSU2 protocol version number
`static int`	`REASON_AEAD` AEAD verification failure
`static int`	`REASON_BANNED` Peer is banned
`static int`	`REASON_FRAME_TIMEOUT` Frame acknowledgment timeout
`static int`	`REASON_FRAMING` Framing protocol error
`static int`	`REASON_LIMITS` Resource limits exceeded
`static int`	`REASON_MSG1` Error in session request message
`static int`	`REASON_MSG2` Error in session created message
`static int`	`REASON_MSG3` Error in session confirmed message
`static int`	`REASON_NETID` Network ID mismatch
`static int`	`REASON_OPTIONS` Options parameter mismatch
`static int`	`REASON_PADDING` Invalid padding
`static int`	`REASON_PAYLOAD` Payload data error
`static int`	`REASON_REPLACED` Session was replaced by a new connection
`static int`	`REASON_S_MISMATCH` Session key mismatch
`static int`	`REASON_SHUTDOWN` Router shutting down
`static int`	`REASON_SIGFAIL` Signature verification failed
`static int`	`REASON_SIGTYPE` Signature type error or mismatch
`static int`	`REASON_SKEW` Clock skew exceeds tolerance
`static int`	`REASON_TERMINATION` Termination requested by remote
`static int`	`REASON_TIMEOUT` Connection timeout
`static int`	`REASON_TOKEN` Token validation error
`static int`	`REASON_UNSPEC` Unspecified reason
`static int`	`REASON_VERSION` Protocol version mismatch
`static int`	`RELAY_ACCEPT` Relay accepted
`static int`	`RELAY_REJECT_BOB_BANNED_CHARLIE` Rejected by Bob: Charlie is banned
`static int`	`RELAY_REJECT_BOB_LIMIT` Rejected by Bob: limit reached
`static int`	`RELAY_REJECT_BOB_NO_TAG` Rejected by Bob: no tag found
`static int`	`RELAY_REJECT_BOB_SIGFAIL` Rejected by Bob: signature failure
`static int`	`RELAY_REJECT_BOB_UNKNOWN_ALICE` Rejected by Bob: unknown Alice
`static int`	`RELAY_REJECT_BOB_UNSPEC` Rejected by Bob: unspecified reason
`static int`	`RELAY_REJECT_CHARLIE_ADDRESS` Rejected by Charlie: address mismatch
`static int`	`RELAY_REJECT_CHARLIE_BANNED` Rejected by Charlie: banned
`static int`	`RELAY_REJECT_CHARLIE_CONNECTED` Rejected by Charlie: already connected
`static int`	`RELAY_REJECT_CHARLIE_LIMIT` Rejected by Charlie: limit reached
`static int`	`RELAY_REJECT_CHARLIE_SIGFAIL` Rejected by Charlie: signature failure
`static int`	`RELAY_REJECT_CHARLIE_UNKNOWN_ALICE` Rejected by Charlie: unknown Alice
`static int`	`RELAY_REJECT_CHARLIE_UNSPEC` Rejected by Charlie: unspecified reason
`static byte[]`	`RELAY_REQUEST_PROLOGUE` Prologue for relay request signatures
`static byte[]`	`RELAY_RESPONSE_PROLOGUE` Prologue for relay response signatures
`static byte`	`RETRY_FLAG_BYTE` Message type flag for retry
`static byte`	`SESSION_CONFIRMED_FLAG_BYTE` Message type flag for session confirmed
`static byte`	`SESSION_CREATED_FLAG_BYTE` Message type flag for session created
`static int`	`SESSION_HEADER_SIZE` 64 bytes, combined long header and key
`static byte`	`SESSION_REQUEST_FLAG_BYTE` The message types, 0-11, as bytes.
`static int`	`SHORT_HEADER_FLAGS_LEN` Length of short header flags in bytes
`static int`	`SHORT_HEADER_FLAGS_OFFSET` Offset of short header flags
`static int`	`SHORT_HEADER_SIZE` 16 bytes, short (data) header size
`static int`	`SRC_CONN_ID_OFFSET` Offset of source connection ID in long header
`static int`	`TEST_ACCEPT` Peer test accepted
`static int`	`TEST_REJECT_BOB_ADDRESS` Rejected by Bob: address mismatch
`static int`	`TEST_REJECT_BOB_LIMIT` Rejected by Bob: limit reached
`static int`	`TEST_REJECT_BOB_NO_CHARLIE` Rejected by Bob: no Charlie
`static int`	`TEST_REJECT_BOB_SIGFAIL` Rejected by Bob: signature failure
`static int`	`TEST_REJECT_BOB_UNSPEC` Rejected by Bob: unspecified reason
`static int`	`TEST_REJECT_CHARLIE_ADDRESS` Rejected by Charlie: address mismatch
`static int`	`TEST_REJECT_CHARLIE_BANNED` Rejected by Charlie: banned
`static int`	`TEST_REJECT_CHARLIE_CONNECTED` Rejected by Charlie: already connected
`static int`	`TEST_REJECT_CHARLIE_LIMIT` Rejected by Charlie: limit reached
`static int`	`TEST_REJECT_CHARLIE_SIGFAIL` Rejected by Charlie: signature failure
`static int`	`TEST_REJECT_CHARLIE_UNKNOWN_ALICE` Rejected by Charlie: unknown Alice
`static int`	`TEST_REJECT_CHARLIE_UNSPEC` Rejected by Charlie: unspecified reason
`static int`	`TOKEN_OFFSET` Offset of token in long header
`static byte`	`TOKEN_REQUEST_FLAG_BYTE` Message type flag for token request
`static int`	`TOTAL_PROT_SAMPLE_LEN` Total header protection sample length for both samples
`static int`	`TYPE_OFFSET` Offset of message type in header
`static int`	`VERSION_OFFSET` Offset of protocol version in header
`static byte[]`	`ZEROKEY` All-zero key of KEY_LEN bytes
`static byte[]`	`ZEROLEN` Empty byte array, used as HKDF salt

Method Summary

All Methods Static Methods Concrete Methods
Modifier and Type	Method and Description
`static byte[]`	`createPeerTestData(I2PAppContext ctx, Hash h, Hash h2, PeerTestState.Role role, long nonce, byte[] ip, int port, SigningPrivateKey spk)` Make the data for the peer test block
`static byte[]`	`createRelayRequestData(I2PAppContext ctx, Hash h, Hash h2, long nonce, long tag, byte[] ip, int port, SigningPrivateKey spk)` Make the data for the relay request block
`static byte[]`	`createRelayResponseData(I2PAppContext ctx, Hash h, int code, long nonce, byte[] ip, int port, SigningPrivateKey spk, long token)` Make the data for the relay response block
`static byte[]`	`hkdf(I2PAppContext ctx, byte[] key, String info)` 32 byte output, ZEROLEN data
`static Signature`	`sign(I2PAppContext ctx, byte[] prologue, Hash h, Hash h2, byte[] data, int datalen, SigningPrivateKey spk)` Sign the relay or peer test data, using the prologue and hash as the initial data, and then the provided data.
`static String`	`terminationCodeToString(int code)` Convert a termination reason code to a human-readable string
`static boolean`	`validateSig(I2PAppContext ctx, byte[] prologue, Hash h, Hash h2, byte[] data, SigningPublicKey spk)` Validate the signed relay or peer test data, using the prologue and hash as the initial data, and then the provided data which ends with a signature of the specified type.

Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

- Field Detail
  - CHACHA_IV_LEN
```
public static final int CHACHA_IV_LEN
```
    12 bytes, ChaCha20 nonce length
    See Also:
    Constant Field Values
  - DATA_FLAG_BYTE
```
public static final byte DATA_FLAG_BYTE
```
    Message type flag for data
    See Also:
    Constant Field Values
  - DATA_FOLLOWON_EXTRA_SIZE
```
public static final int DATA_FOLLOWON_EXTRA_SIZE
```
    5 for flag and msg number in followon block
    See Also:
    Constant Field Values
  - DATA_HEADER_SIZE
```
public static final int DATA_HEADER_SIZE
```
    16 byte short header
    See Also:
    Constant Field Values
  - DEST_CONN_ID_OFFSET
```
public static final int DEST_CONN_ID_OFFSET
```
    Offset of destination connection ID in header
    See Also:
    Constant Field Values
  - FIRST_FRAGMENT_HEADER_SIZE
```
public static final int FIRST_FRAGMENT_HEADER_SIZE
```
    3 byte block header
    See Also:
    Constant Field Values
  - FOLLOWON_FRAGMENT_HEADER_SIZE
```
public static final int FOLLOWON_FRAGMENT_HEADER_SIZE
```
    3 byte block header + 4 byte msg ID + 1 byte fragment info = 8
    See Also:
    Constant Field Values
  - HEADER_PROT_1_OFFSET
```
public static final int HEADER_PROT_1_OFFSET
```
    Offset of first header protection region (dest conn ID)
    See Also:
    Constant Field Values
  - HEADER_PROT_2_OFFSET
```
public static final int HEADER_PROT_2_OFFSET
```
    Offset of second header protection region (packet number)
    See Also:
    Constant Field Values
  - HEADER_PROT_DATA_LEN
```
public static final int HEADER_PROT_DATA_LEN
```
    Length of header protection data in bytes
    See Also:
    Constant Field Values
  - HEADER_PROT_SAMPLE_1_OFFSET
```
public static final int HEADER_PROT_SAMPLE_1_OFFSET
```
    Offset of first header protection sample
    See Also:
    Constant Field Values
  - HEADER_PROT_SAMPLE_2_OFFSET
```
public static final int HEADER_PROT_SAMPLE_2_OFFSET
```
    Offset of second header protection sample
    See Also:
    Constant Field Values
  - HEADER_PROT_SAMPLE_LEN
```
public static final int HEADER_PROT_SAMPLE_LEN
```
    Length of header protection sample in bytes
    See Also:
    Constant Field Values
  - HOLE_PUNCH_FLAG_BYTE
```
public static final byte HOLE_PUNCH_FLAG_BYTE
```
    Message type flag for hole punch
    See Also:
    Constant Field Values
  - INFO_CONFIRMED
```
public static final String INFO_CONFIRMED
```
    HKDF info string for session confirmed key derivation
    See Also:
    Constant Field Values
  - INFO_CREATED
```
public static final String INFO_CREATED
```
    HKDF info string for session created header key derivation
    See Also:
    Constant Field Values
  - INFO_DATA
```
public static final String INFO_DATA
```
    HKDF info string for data packet key derivation
    See Also:
    Constant Field Values
  - INTRO_KEY_LEN
```
public static final int INTRO_KEY_LEN
```
    32 bytes, introductory key length
    See Also:
    Constant Field Values
  - KEY_LEN
```
public static final int KEY_LEN
```
    32 bytes, X25519 public key length
  - LONG_HEADER_FLAGS_OFFSET
```
public static final int LONG_HEADER_FLAGS_OFFSET
```
    Offset of long header flags
    See Also:
    Constant Field Values
  - LONG_HEADER_SIZE
```
public static final int LONG_HEADER_SIZE
```
    32 bytes, long (handshake) header size
    See Also:
    Constant Field Values
  - MAC_LEN
```
public static final int MAC_LEN
```
    16 bytes, MAC tag length
    See Also:
    Constant Field Values
  - MIN_DATA_LEN
```
public static final int MIN_DATA_LEN
```
    Short message type (e.g. data) minimum length in bytes (40).
    See Also:
    Constant Field Values
  - MIN_HANDSHAKE_DATA_LEN
```
public static final int MIN_HANDSHAKE_DATA_LEN
```
    Handshake message type minimum length in bytes (88).
  - MIN_LONG_DATA_LEN
```
public static final int MIN_LONG_DATA_LEN
```
    Long message type minimum length in bytes (56).
    See Also:
    Constant Field Values
  - MIN_RETRY_LEN
```
public static final int MIN_RETRY_LEN
```
    Retry message minimum length in bytes (56).
    See Also:
    Constant Field Values
  - MIN_SESSION_CREATED_LEN
```
public static final int MIN_SESSION_CREATED_LEN
```
    Session created minimum length in bytes (88).
  - MIN_SESSION_REQUEST_LEN
```
public static final int MIN_SESSION_REQUEST_LEN
```
    Session request minimum length in bytes (88).
  - MIN_TOKEN_REQUEST_LEN
```
public static final int MIN_TOKEN_REQUEST_LEN
```
    Token request minimum length in bytes (56).
    See Also:
    Constant Field Values
  - NETID_OFFSET
```
public static final int NETID_OFFSET
```
    Offset of network ID in header
    See Also:
    Constant Field Values
  - PADDING_MAX
```
public static final int PADDING_MAX
```
    Maximum padding for data packets
    See Also:
    Constant Field Values
  - PADDING_MAX_SESSION_CREATED
```
public static final int PADDING_MAX_SESSION_CREATED
```
    Maximum padding for session created
    See Also:
    Constant Field Values
  - PADDING_MAX_SESSION_REQUEST
```
public static final int PADDING_MAX_SESSION_REQUEST
```
    Maximum padding for session request
    See Also:
    Constant Field Values
  - PEER_TEST_FLAG_BYTE
```
public static final byte PEER_TEST_FLAG_BYTE
```
    Message type flag for peer test
    See Also:
    Constant Field Values
  - PEER_TEST_PROLOGUE
```
public static final byte[] PEER_TEST_PROLOGUE
```
    Prologue for peer test signatures
  - PKT_NUM_LEN
```
public static final int PKT_NUM_LEN
```
    Length of packet number field in bytes
    See Also:
    Constant Field Values
  - PKT_NUM_OFFSET
```
public static final int PKT_NUM_OFFSET
```
    Offset of packet number in header
    See Also:
    Constant Field Values
  - PROTOCOL_VERSION
```
public static final int PROTOCOL_VERSION
```
    SSU2 protocol version number
    See Also:
    Constant Field Values
  - REASON_AEAD
```
public static final int REASON_AEAD
```
    AEAD verification failure
    See Also:
    Constant Field Values
  - REASON_BANNED
```
public static final int REASON_BANNED
```
    Peer is banned
    See Also:
    Constant Field Values
  - REASON_FRAME_TIMEOUT
```
public static final int REASON_FRAME_TIMEOUT
```
    Frame acknowledgment timeout
    See Also:
    Constant Field Values
  - REASON_FRAMING
```
public static final int REASON_FRAMING
```
    Framing protocol error
    See Also:
    Constant Field Values
  - REASON_LIMITS
```
public static final int REASON_LIMITS
```
    Resource limits exceeded
    See Also:
    Constant Field Values
  - REASON_MSG1
```
public static final int REASON_MSG1
```
    Error in session request message
    See Also:
    Constant Field Values
  - REASON_MSG2
```
public static final int REASON_MSG2
```
    Error in session created message
    See Also:
    Constant Field Values
  - REASON_MSG3
```
public static final int REASON_MSG3
```
    Error in session confirmed message
    See Also:
    Constant Field Values
  - REASON_NETID
```
public static final int REASON_NETID
```
    Network ID mismatch
    See Also:
    Constant Field Values
  - REASON_OPTIONS
```
public static final int REASON_OPTIONS
```
    Options parameter mismatch
    See Also:
    Constant Field Values
  - REASON_PADDING
```
public static final int REASON_PADDING
```
    Invalid padding
    See Also:
    Constant Field Values
  - REASON_PAYLOAD
```
public static final int REASON_PAYLOAD
```
    Payload data error
    See Also:
    Constant Field Values
  - REASON_REPLACED
```
public static final int REASON_REPLACED
```
    Session was replaced by a new connection
    See Also:
    Constant Field Values
  - REASON_S_MISMATCH
```
public static final int REASON_S_MISMATCH
```
    Session key mismatch
    See Also:
    Constant Field Values
  - REASON_SHUTDOWN
```
public static final int REASON_SHUTDOWN
```
    Router shutting down
    See Also:
    Constant Field Values
  - REASON_SIGFAIL
```
public static final int REASON_SIGFAIL
```
    Signature verification failed
    See Also:
    Constant Field Values
  - REASON_SIGTYPE
```
public static final int REASON_SIGTYPE
```
    Signature type error or mismatch
    See Also:
    Constant Field Values
  - REASON_SKEW
```
public static final int REASON_SKEW
```
    Clock skew exceeds tolerance
    See Also:
    Constant Field Values
  - REASON_TERMINATION
```
public static final int REASON_TERMINATION
```
    Termination requested by remote
    See Also:
    Constant Field Values
  - REASON_TIMEOUT
```
public static final int REASON_TIMEOUT
```
    Connection timeout
    See Also:
    Constant Field Values
  - REASON_TOKEN
```
public static final int REASON_TOKEN
```
    Token validation error
    See Also:
    Constant Field Values
  - REASON_UNSPEC
```
public static final int REASON_UNSPEC
```
    Unspecified reason
    See Also:
    Constant Field Values
  - REASON_VERSION
```
public static final int REASON_VERSION
```
    Protocol version mismatch
    See Also:
    Constant Field Values
  - RELAY_ACCEPT
```
public static final int RELAY_ACCEPT
```
    Relay accepted
    See Also:
    Constant Field Values
  - RELAY_REJECT_BOB_BANNED_CHARLIE
```
public static final int RELAY_REJECT_BOB_BANNED_CHARLIE
```
    Rejected by Bob: Charlie is banned
    See Also:
    Constant Field Values
  - RELAY_REJECT_BOB_LIMIT
```
public static final int RELAY_REJECT_BOB_LIMIT
```
    Rejected by Bob: limit reached
    See Also:
    Constant Field Values
  - RELAY_REJECT_BOB_NO_TAG
```
public static final int RELAY_REJECT_BOB_NO_TAG
```
    Rejected by Bob: no tag found
    See Also:
    Constant Field Values
  - RELAY_REJECT_BOB_SIGFAIL
```
public static final int RELAY_REJECT_BOB_SIGFAIL
```
    Rejected by Bob: signature failure
    See Also:
    Constant Field Values
  - RELAY_REJECT_BOB_UNKNOWN_ALICE
```
public static final int RELAY_REJECT_BOB_UNKNOWN_ALICE
```
    Rejected by Bob: unknown Alice
    See Also:
    Constant Field Values
  - RELAY_REJECT_BOB_UNSPEC
```
public static final int RELAY_REJECT_BOB_UNSPEC
```
    Rejected by Bob: unspecified reason
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_ADDRESS
```
public static final int RELAY_REJECT_CHARLIE_ADDRESS
```
    Rejected by Charlie: address mismatch
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_BANNED
```
public static final int RELAY_REJECT_CHARLIE_BANNED
```
    Rejected by Charlie: banned
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_CONNECTED
```
public static final int RELAY_REJECT_CHARLIE_CONNECTED
```
    Rejected by Charlie: already connected
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_LIMIT
```
public static final int RELAY_REJECT_CHARLIE_LIMIT
```
    Rejected by Charlie: limit reached
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_SIGFAIL
```
public static final int RELAY_REJECT_CHARLIE_SIGFAIL
```
    Rejected by Charlie: signature failure
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_UNKNOWN_ALICE
```
public static final int RELAY_REJECT_CHARLIE_UNKNOWN_ALICE
```
    Rejected by Charlie: unknown Alice
    See Also:
    Constant Field Values
  - RELAY_REJECT_CHARLIE_UNSPEC
```
public static final int RELAY_REJECT_CHARLIE_UNSPEC
```
    Rejected by Charlie: unspecified reason
    See Also:
    Constant Field Values
  - RELAY_REQUEST_PROLOGUE
```
public static final byte[] RELAY_REQUEST_PROLOGUE
```
    Prologue for relay request signatures
  - RELAY_RESPONSE_PROLOGUE
```
public static final byte[] RELAY_RESPONSE_PROLOGUE
```
    Prologue for relay response signatures
  - RETRY_FLAG_BYTE
```
public static final byte RETRY_FLAG_BYTE
```
    Message type flag for retry
    See Also:
    Constant Field Values
  - SESSION_CONFIRMED_FLAG_BYTE
```
public static final byte SESSION_CONFIRMED_FLAG_BYTE
```
    Message type flag for session confirmed
    See Also:
    Constant Field Values
  - SESSION_CREATED_FLAG_BYTE
```
public static final byte SESSION_CREATED_FLAG_BYTE
```
    Message type flag for session created
    See Also:
    Constant Field Values
  - SESSION_HEADER_SIZE
```
public static final int SESSION_HEADER_SIZE
```
    64 bytes, combined long header and key
  - SESSION_REQUEST_FLAG_BYTE
```
public static final byte SESSION_REQUEST_FLAG_BYTE
```
    The message types, 0-11, as bytes. Message type flag for session request.
    See Also:
    Constant Field Values
  - SHORT_HEADER_FLAGS_LEN
```
public static final int SHORT_HEADER_FLAGS_LEN
```
    Length of short header flags in bytes
    See Also:
    Constant Field Values
  - SHORT_HEADER_FLAGS_OFFSET
```
public static final int SHORT_HEADER_FLAGS_OFFSET
```
    Offset of short header flags
    See Also:
    Constant Field Values
  - SHORT_HEADER_SIZE
```
public static final int SHORT_HEADER_SIZE
```
    16 bytes, short (data) header size
    See Also:
    Constant Field Values
  - SRC_CONN_ID_OFFSET
```
public static final int SRC_CONN_ID_OFFSET
```
    Offset of source connection ID in long header
    See Also:
    Constant Field Values
  - TEST_ACCEPT
```
public static final int TEST_ACCEPT
```
    Peer test accepted
    See Also:
    Constant Field Values
  - TEST_REJECT_BOB_ADDRESS
```
public static final int TEST_REJECT_BOB_ADDRESS
```
    Rejected by Bob: address mismatch
    See Also:
    Constant Field Values
  - TEST_REJECT_BOB_LIMIT
```
public static final int TEST_REJECT_BOB_LIMIT
```
    Rejected by Bob: limit reached
    See Also:
    Constant Field Values
  - TEST_REJECT_BOB_NO_CHARLIE
```
public static final int TEST_REJECT_BOB_NO_CHARLIE
```
    Rejected by Bob: no Charlie
    See Also:
    Constant Field Values
  - TEST_REJECT_BOB_SIGFAIL
```
public static final int TEST_REJECT_BOB_SIGFAIL
```
    Rejected by Bob: signature failure
    See Also:
    Constant Field Values
  - TEST_REJECT_BOB_UNSPEC
```
public static final int TEST_REJECT_BOB_UNSPEC
```
    Rejected by Bob: unspecified reason
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_ADDRESS
```
public static final int TEST_REJECT_CHARLIE_ADDRESS
```
    Rejected by Charlie: address mismatch
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_BANNED
```
public static final int TEST_REJECT_CHARLIE_BANNED
```
    Rejected by Charlie: banned
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_CONNECTED
```
public static final int TEST_REJECT_CHARLIE_CONNECTED
```
    Rejected by Charlie: already connected
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_LIMIT
```
public static final int TEST_REJECT_CHARLIE_LIMIT
```
    Rejected by Charlie: limit reached
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_SIGFAIL
```
public static final int TEST_REJECT_CHARLIE_SIGFAIL
```
    Rejected by Charlie: signature failure
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_UNKNOWN_ALICE
```
public static final int TEST_REJECT_CHARLIE_UNKNOWN_ALICE
```
    Rejected by Charlie: unknown Alice
    See Also:
    Constant Field Values
  - TEST_REJECT_CHARLIE_UNSPEC
```
public static final int TEST_REJECT_CHARLIE_UNSPEC
```
    Rejected by Charlie: unspecified reason
    See Also:
    Constant Field Values
  - TOKEN_OFFSET
```
public static final int TOKEN_OFFSET
```
    Offset of token in long header
    See Also:
    Constant Field Values
  - TOKEN_REQUEST_FLAG_BYTE
```
public static final byte TOKEN_REQUEST_FLAG_BYTE
```
    Message type flag for token request
    See Also:
    Constant Field Values
  - TOTAL_PROT_SAMPLE_LEN
```
public static final int TOTAL_PROT_SAMPLE_LEN
```
    Total header protection sample length for both samples
    See Also:
    Constant Field Values
  - TYPE_OFFSET
```
public static final int TYPE_OFFSET
```
    Offset of message type in header
    See Also:
    Constant Field Values
  - VERSION_OFFSET
```
public static final int VERSION_OFFSET
```
    Offset of protocol version in header
    See Also:
    Constant Field Values
  - ZEROKEY
```
public static final byte[] ZEROKEY
```
    All-zero key of KEY_LEN bytes
  - ZEROLEN
```
public static final byte[] ZEROLEN
```
    Empty byte array, used as HKDF salt
- Method Detail
  - createPeerTestData
```
public static byte[] createPeerTestData(I2PAppContext ctx,
                                        Hash h,
                                        Hash h2,
                                        PeerTestState.Role role,
                                        long nonce,
                                        byte[] ip,
                                        int port,
                                        SigningPrivateKey spk)
```
    Make the data for the peer test block
    Parameters:
    h - to be included in sig, not included in data
    h2 - may be null, to be included in sig, not included in data
    role - unused
    ip - may be null
    Returns:
    null on failure
  - createRelayRequestData
```
public static byte[] createRelayRequestData(I2PAppContext ctx,
                                            Hash h,
                                            Hash h2,
                                            long nonce,
                                            long tag,
                                            byte[] ip,
                                            int port,
                                            SigningPrivateKey spk)
```
    Make the data for the relay request block
    Parameters:
    h - Bob hash to be included in sig, not included in data
    h2 - Charlie hash to be included in sig, not included in data
    ip - non-null
    Returns:
    null on failure
  - createRelayResponseData
```
public static byte[] createRelayResponseData(I2PAppContext ctx,
                                             Hash h,
                                             int code,
                                             long nonce,
                                             byte[] ip,
                                             int port,
                                             SigningPrivateKey spk,
                                             long token)
```
    Make the data for the relay response block
    Parameters:
    h - Bob hash to be included in sig, not included in data
    ip - may be null
    port - the UDP port number if ip is null
    token - if nonzero, append it
    Returns:
    null on failure
  - hkdf
```
public static byte[] hkdf(I2PAppContext ctx,
                          byte[] key,
                          String info)
```
    32 byte output, ZEROLEN data
  - sign
```
public static Signature sign(I2PAppContext ctx,
                             byte[] prologue,
                             Hash h,
                             Hash h2,
                             byte[] data,
                             int datalen,
                             SigningPrivateKey spk)
```
    Sign the relay or peer test data, using the prologue and hash as the initial data, and then the provided data.
    Parameters:
    data - if desired, leave room at end for sig
    datalen - the length of the data to be signed
    h - to be included in sig, not included in data
    h2 - may be null, to be included in sig, not included in data
    Returns:
    null on failure
  - terminationCodeToString
```
public static String terminationCodeToString(int code)
```
    Convert a termination reason code to a human-readable string
    Parameters:
    code - one of the REASON_* constants
    Returns:
    human-readable description
  - validateSig
```
public static boolean validateSig(I2PAppContext ctx,
                                  byte[] prologue,
                                  Hash h,
                                  Hash h2,
                                  byte[] data,
                                  SigningPublicKey spk)
```
    Validate the signed relay or peer test data, using the prologue and hash as the initial data, and then the provided data which ends with a signature of the specified type.
    Parameters:
    h2 - may be null
    data - not including relay response token

Class SSU2Util

Field Summary

Method Summary

Methods inherited from class java.lang.Object

Field Detail

CHACHA_IV_LEN

DATA_FLAG_BYTE

DATA_FOLLOWON_EXTRA_SIZE

DATA_HEADER_SIZE

DEST_CONN_ID_OFFSET

FIRST_FRAGMENT_HEADER_SIZE

FOLLOWON_FRAGMENT_HEADER_SIZE

HEADER_PROT_1_OFFSET

HEADER_PROT_2_OFFSET

HEADER_PROT_DATA_LEN

HEADER_PROT_SAMPLE_1_OFFSET

HEADER_PROT_SAMPLE_2_OFFSET

HEADER_PROT_SAMPLE_LEN

HOLE_PUNCH_FLAG_BYTE

INFO_CONFIRMED

INFO_CREATED

INFO_DATA

INTRO_KEY_LEN

KEY_LEN

LONG_HEADER_FLAGS_OFFSET

LONG_HEADER_SIZE

MAC_LEN

MIN_DATA_LEN

MIN_HANDSHAKE_DATA_LEN

MIN_LONG_DATA_LEN

MIN_RETRY_LEN

MIN_SESSION_CREATED_LEN

MIN_SESSION_REQUEST_LEN

MIN_TOKEN_REQUEST_LEN

NETID_OFFSET

PADDING_MAX

PADDING_MAX_SESSION_CREATED

PADDING_MAX_SESSION_REQUEST

PEER_TEST_FLAG_BYTE

PEER_TEST_PROLOGUE

PKT_NUM_LEN

PKT_NUM_OFFSET

PROTOCOL_VERSION

REASON_AEAD

REASON_BANNED

REASON_FRAME_TIMEOUT

REASON_FRAMING

REASON_LIMITS

REASON_MSG1

REASON_MSG2

REASON_MSG3

REASON_NETID

REASON_OPTIONS

REASON_PADDING

REASON_PAYLOAD

REASON_REPLACED

REASON_S_MISMATCH

REASON_SHUTDOWN

REASON_SIGFAIL

REASON_SIGTYPE

REASON_SKEW

REASON_TERMINATION

REASON_TIMEOUT

REASON_TOKEN

REASON_UNSPEC

REASON_VERSION

RELAY_ACCEPT

RELAY_REJECT_BOB_BANNED_CHARLIE

RELAY_REJECT_BOB_LIMIT

RELAY_REJECT_BOB_NO_TAG

RELAY_REJECT_BOB_SIGFAIL

RELAY_REJECT_BOB_UNKNOWN_ALICE

RELAY_REJECT_BOB_UNSPEC

RELAY_REJECT_CHARLIE_ADDRESS

RELAY_REJECT_CHARLIE_BANNED

RELAY_REJECT_CHARLIE_CONNECTED

RELAY_REJECT_CHARLIE_LIMIT

RELAY_REJECT_CHARLIE_SIGFAIL

RELAY_REJECT_CHARLIE_UNKNOWN_ALICE

RELAY_REJECT_CHARLIE_UNSPEC