From d51e4db465b30d104b9f4a8ef8a199b56091b1f1 Mon Sep 17 00:00:00 2001
From: zzz <zzz@mail.i2p>
Date: Tue, 17 Apr 2018 16:11:51 +0000
Subject: [PATCH] Updates from 2018-04-16 review
---
i2p2www/spec/proposals/111-ntcp-2.rst | 54 ++++++++++++++++++++-------
1 file changed, 40 insertions(+), 14 deletions(-)
diff --git a/i2p2www/spec/proposals/111-ntcp-2.rst b/i2p2www/spec/proposals/111-ntcp-2.rst
index 99becfbbf..30f08765d 100644
--- a/i2p2www/spec/proposals/111-ntcp-2.rst
+++ b/i2p2www/spec/proposals/111-ntcp-2.rst
@@ -6,7 +6,7 @@ NTCP 2
:editor: manas, str4d
:created: 2014-02-13
:thread: http://zzz.i2p/topics/1577
- :lastupdated: 2018-04-16
+ :lastupdated: 2018-04-17
:status: Open
:supercedes: 106
@@ -312,7 +312,8 @@ Noise Protocol Framework
========================
This proposal provides the requirements based on the Noise Protocol Framework
-[NOISE]_. Noise has similar properties to the Station-To-Station protocol
+[NOISE]_ (Revision 33, 2017-10-04).
+Noise has similar properties to the Station-To-Station protocol
[STS]_, which is the basis for the [SSU]_ protocol. In Noise parlance, Alice
is the initiator, and Bob is the responder.
@@ -1609,16 +1610,12 @@ and treat them as padding.
Encrypted data is 65535 bytes max, including a 16-byte authentication header,
so the max unencrypted data is 65519 bytes.
-
+(Poly1305 auth tag not shown):
.. raw:: html
{% highlight lang='dataspec' %}
+----+----+----+----+----+----+----+----+
- | Poly1305 auth tag |
- + (16 bytes) +
- | |
- +----+----+----+----+----+----+----+----+
|blk | size | data |
+----+----+----+ +
| |
@@ -1678,6 +1675,9 @@ Options
Pass updated options.
Options include: Min and max padding.
+Options block will be variable length.
+
+
.. raw:: html
{% highlight lang='dataspec' %}
@@ -1698,6 +1698,7 @@ Options include: Min and max padding.
Max is for bandwidth limits.
4 bytes tx_pad_min, tx_pad_max, rx_pad_min, rx_pad_max
Each is a 4.4 fixed-point float representing 0 to 15.9375
+ (or think of it as an unsigned 8-bit integer divided by 16.0).
This is the ratio of padding to data. Examples:
Value of 0x00 means no padding
Value of 0x01 means add 6% padding
@@ -1714,6 +1715,11 @@ Options include: Min and max padding.
{% endhighlight %}
+Options Issues
+``````````````
+- Options format is TBD.
+- Options negotiation is TBD.
+
RouterInfo
``````````
@@ -1838,9 +1844,11 @@ This should be the last non-padding block.
5: incompatible options
6: incompatible sig type
7: clock skew
- 8: other error
+ 8: padding violation
+ 9: AEAD framing error
+ 10: payload framing error
...
- last valid nonce received: The nonce for the last valid AEAD block received
+ last valid nonce received: The nonce (counter) for the last valid AEAD block received
8 bytes
Note: Not all reasons may actually be used; handshake failures will
@@ -1863,6 +1871,7 @@ Updated options may be sent during the data phase.
See options block information above.
+
.. raw:: html
{% highlight lang='dataspec' %}
@@ -1880,6 +1889,19 @@ See options block information above.
{% endhighlight %}
+Padding Issues
+``````````````
+- Padding strategies TBD.
+- Minimum padding TBD.
+- Need for padding-only messages TBD.
+- Padding defaults TBD.
+- Padding parameter negotiation TBD.
+- Is padding important for data phase or only handshake?
+- How to ensure low-bandwidth routers aren't "swamped"
+- How to ensure high-bandwidth routers send/receive enough padding
+- Noise limits messages to 64KB, any other padding (except in handshake msg 1/2)
+ would have to be outside Noise.
+- Disconnect if negotiated padding is violated or can't negotiate?
Other block types
@@ -1969,13 +1991,15 @@ When published as "NTCP2" with "n", "s", "i", and "v" options,
the router accepts incoming connections on that host and port
for the NTCP2 protocol only.
+If a router supports both NTCP1 and NTCP2 connections but
+does not implement automatic version detection for incoming connections,
+it must advertise both "NTCP" and "NTCP2" addresses, and include
+the ntcp2 options in the "NTCP2" address only.
+
If multiple NTCP2 RouterAddresses (either as "NTCP" or "NTCP2") are published
in the same RouterInfo (for additional IP addresses or ports),
-all must contain the identical three options and values.
-In particular, all must contain the same static key "s".
-
-TBD: May different RouterAddresses for different IP addresses/ports
-contain different IV options? This may cause problems on Windows.
+all addressses specifying the same port must contain the identical ntcp2 options and values.
+In particular, all must contain the same static key and iv.
@@ -1995,6 +2019,8 @@ The option name is N(shortened Noise name)(NTCP2 Version)s.
Base 64 encoded using the standard I2P Base 64 alphabet.
32 bytes in binary, 44 bytes as Base 64 encoded,
little-endian X25519 public key.
+ TODO: There may be value in using the "official" noise name,
+ at a cost of 26 bytes per address.
--
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