diff --git a/i2p2www/spec/proposals/157-new-tbm.rst b/i2p2www/spec/proposals/157-new-tbm.rst index 35e296244d627bb2141125b74ecb3041723ff2b2..6764242af85772ce72659cccad7b367565b74f17 100644 --- a/i2p2www/spec/proposals/157-new-tbm.rst +++ b/i2p2www/spec/proposals/157-new-tbm.rst @@ -5,7 +5,7 @@ Smaller Tunnel Build Messages :author: zzz, orignal :created: 2020-10-09 :thread: http://zzz.i2p/topics/2957 - :lastupdated: 2021-07-13 + :lastupdated: 2021-07-28 :status: Open :target: 0.9.51 @@ -534,20 +534,6 @@ Implementation Notes Issues ====== -- HKDF details -- Layer encryption changes? - - Should we do additional hiding from the paired OBEP or IBGW? Garlic? -- For an IB build, the build message could be garlic encrypted to the IBGW, - but then it would be larger. -- We could do this for IB now for existing build messages if desired, - but it's more expensive for ElGamal. -- Is it worth it, or does the size of the message (much larger than - typical database lookup, but maybe not database store) plus the - delivery instructions make it obvious anyway? -- For an OB build, the build reply message would have to be garlic encrypted - by the OBEP to the originator, but that would not be anonymous. - Is there another way? probably not. Migration @@ -683,8 +669,10 @@ Current build record cleartext size before unused padding: 193 Removal of full router hash and HKDF generation of keys/IVs would free up plenty of room for future options. If everything is HKDF, required cleartext space is about 58 bytes (without any options). -OTBRM is much smaller because there's one small plaintext record and one less encrypted record. - +The garlic-wrapped OTBRM will be slightly smaller than the garlic-wrapped STBM, +because the delivery instructions are LOCAL not ROUTER, +there's no DATETIME block included, and +it uses an 8-byte tag rather than the 32-byte ephemeral key for a full 'N' message.