From 53bc04f4025ea2d5c579bd7758d2f3f95679a94b Mon Sep 17 00:00:00 2001
From: zzz <zzz@i2pmail.org>
Date: Tue, 26 Oct 2021 14:57:43 -0400
Subject: [PATCH] sublist try 4
---
i2p2www/spec/proposals/159-ssu2.rst | 51 +++++++++++++++--------------
1 file changed, 27 insertions(+), 24 deletions(-)
diff --git a/i2p2www/spec/proposals/159-ssu2.rst b/i2p2www/spec/proposals/159-ssu2.rst
index 47e7afe0e..51e1c31ce 100644
--- a/i2p2www/spec/proposals/159-ssu2.rst
+++ b/i2p2www/spec/proposals/159-ssu2.rst
@@ -5800,6 +5800,7 @@ Therefore, the recommended processing steps in the receiver loop logic are:
1) Decrypt the first 16 bytes with ChaCha20 using the local router hash
as the key with n=0, to recover the session ID.
If the session ID matches a current or pending inbound session:
+
a) Using the session's header protection key, remove the header protection
to recover the version, net ID, and message type at bytes 8-15.
b) If the message type is Session Confirmed, it is a long header.
@@ -5829,17 +5830,18 @@ Therefore, the recommended processing steps in the receiver loop logic are:
Verify the net ID and protocol version are valid, and
the message type is Session Request, or other message type
allowed out-of-session (TBD).
+
a) If all is valid and the message type is Session Request,
decrypt the next 16 bytes of the header and the 32-byte X value
with ChaCha20 using the local intro key with n=1.
- - If the token at header bytes 24-31 is accepted,
- then MixHash() the decrypted 32 byte header and
- decrypt the message with Noise.
- Send a Session Created in response.
- - If the token is not accepted, send a Retry message to the
- source IP/port with a token. Do not attempt to
- decrypt the message with Noise to avoid DDoS attacks.
+ - If the token at header bytes 24-31 is accepted,
+ then MixHash() the decrypted 32 byte header and
+ decrypt the message with Noise.
+ Send a Session Created in response.
+ - If the token is not accepted, send a Retry message to the
+ source IP/port with a token. Do not attempt to
+ decrypt the message with Noise to avoid DDoS attacks.
b) If the message type is some other message that is valid
out-of-session, presumably with a short header,
@@ -5850,6 +5852,7 @@ Therefore, the recommended processing steps in the receiver loop logic are:
3) Look up a pending outbound session by the source IP/port of the packet.
+
a) If found, decrypt the first 16 bytes with ChaCha20 using Bob's router hash
as the key with n=0, to recover the session ID.
b) If the session ID matches the pending session:
@@ -5859,23 +5862,23 @@ Therefore, the recommended processing steps in the receiver loop logic are:
the message type is Session Response or Retry, or other message type
allowed out-of-session (TBD).
- - If all is valid and the message type is Session Response,
- decrypt the next 16 bytes of the header and the 32-byte Y value
- with ChaCha20 using Bob's router hash as the key with n=1.
- Then MixHash() the decrypted 32 byte header and
- decrypt the message with Noise.
- Send a Session Confirmed in response.
- - If all is valid and the message type is Retry,
- decrypt the next 16 bytes of the header
- with ChaCha20 using Bob's router hash as the key with n=1.
- Validate the remaining data (padding) and MAC using ChaCha20/Poly1305 using
- TBD as the key and TBD as the nonce and the decrypted 32-byte header as the AD.
- Resend a Session Request with the received token in response.
- - If the message type is some other message that is valid
- out-of-session, presumably with a short header,
- decrypt the rest of the message with ChaCha20/Poly1305
- using the intro key (TBD), using the decrypted 16-byte header
- as the AD. Process the message.
+ - If all is valid and the message type is Session Response,
+ decrypt the next 16 bytes of the header and the 32-byte Y value
+ with ChaCha20 using Bob's router hash as the key with n=1.
+ Then MixHash() the decrypted 32 byte header and
+ decrypt the message with Noise.
+ Send a Session Confirmed in response.
+ - If all is valid and the message type is Retry,
+ decrypt the next 16 bytes of the header
+ with ChaCha20 using Bob's router hash as the key with n=1.
+ Validate the remaining data (padding) and MAC using ChaCha20/Poly1305 using
+ TBD as the key and TBD as the nonce and the decrypted 32-byte header as the AD.
+ Resend a Session Request with the received token in response.
+ - If the message type is some other message that is valid
+ out-of-session, presumably with a short header,
+ decrypt the rest of the message with ChaCha20/Poly1305
+ using the intro key (TBD), using the decrypted 16-byte header
+ as the AD. Process the message.
c) If a pending outbound session is not found,
or the session ID does not match the pending session, drop the message,
--
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