[tor-commits] [torspec/master] prop224: In cells, replace TYPE/LEN/KEY with just TYPE/KEY.

[asn at torproject.org]

commit 83a62b6e0f31dcb8fbe917ac9d406b78193605b7
Author: George Kadianakis <desnacked at riseup.net>
Date:   Tue Mar 15 15:28:25 2016 +0200

    prop224: In cells, replace TYPE/LEN/KEY with just TYPE/KEY.
---
 proposals/224-rend-spec-ng.txt | 45 +++++++++++++++++++++++++++---------------
 1 file changed, 29 insertions(+), 16 deletions(-)

diff --git a/proposals/224-rend-spec-ng.txt b/proposals/224-rend-spec-ng.txt
index dd76e36..d80b2d5 100644
--- a/proposals/224-rend-spec-ng.txt
+++ b/proposals/224-rend-spec-ng.txt
@@ -153,6 +153,18 @@ Status: Draft
    themselves, but over those strings prefixed with a distinguishing
    value.
 
+   Through this proposal we use the following construction when sending
+   cryptographic keys in tor cells:
+
+        KEYTYPE         [1 byte]
+        KEY             [depends on KEYTYPE]
+
+   In this case the size of the KEY depends on the KEYTYPE. Here are the
+   currently defined key types:
+
+     * The KEYTYPE value [01] is for Ed25519 keys (size: 32 bytes).
+     * The KEYTYPE value [02] is for Curve25519 keys (size: 32 bytes).
+     * The KEYTYPE value [03] is for truncated Curve25519 keys (size: 8 bytes).
 
 0.4. Protocol building blocks [BUILDING-BLOCKS]
 
@@ -1182,14 +1194,11 @@ Status: Draft
       NUMKEYS         [1 byte]
       NUMKEYS times:
         KEYTYPE         [1 byte]
-        KEYLEN          [1 byte]
-        KEY             [KEYLEN bytes]
+        KEY             [depends on KEYTYPE]
       COUNTER         [4 bytes]
       SIGLEN          [1 byte]
       SIGNATURE       [SIGLEN bytes.]
 
-   The KEYTYPE value [01] is for Curve25519 keys.
-
    The COUNTER field is a monotonically increasing value across a given
    introduction point authentication key.
 
@@ -1252,9 +1261,11 @@ Status: Draft
 
    An INTRODUCE1 cell has the following contents:
 
-     AUTH_KEYID      [32 bytes]
-     ENC_KEYID       [8 bytes]
-     N_EXTENSIONS    [1 Byte]
+     AUTH_KEYTYPE    [1 byte]
+     AUTH_KEYID      [depends on AUTH_KEYTYPE]
+     ENC_KEYTYPE     [1 byte]
+     ENC_KEYID       [depends on ENC_KEYTYPE]
+     N_EXTENSIONS    [1 byte]
      N_EXTENSIONS times:
        EXT_FIELD_TYPE [1 byte]
        EXT_FIELD_LEN  [1 byte]
@@ -1275,12 +1286,12 @@ Status: Draft
    running whose PK_ID is the first 20 bytes of AUTH_KEYID.  If so, it
    behaves as in rend-spec.txt.)
 
-   The AUTH_KEYID for an Ed25519 public key is the public key itself.
-   The ENC_KEYID for a Curve25519 public key is the first 8 bytes of the
-   public key. (This key ID is safe to truncate, since all the keys are
-   generated by the hidden service host, and the ID is only valid
-   relative to a single AUTH_KEYID.)  The ENCRYPTED field is as
-   described in 3.3 below.
+   The AUTH_KEYTYPE is an Ed25519 public key (value [01]).
+
+   The ENC_KEYTYPE is a truncated Curve25519 public key (value [03]). (This key
+   is safe to truncate, since all the keys are generated by the hidden service
+   host, and the ID is only valid relative to a single AUTH_KEYID.)  The
+   ENCRYPTED field is as described in 3.3 below.
 
    To relay an INTRODUCE1 cell, the introduction point sends an
    INTRODUCE2 cell with exactly the same contents.
@@ -1360,7 +1371,7 @@ Status: Draft
           EXT_FIELD_TYPE                         [1 byte]
           EXT_FIELD_LEN                          [1 byte]
           EXT_FIELD                              [EXT_FIELD_LEN bytes]
-      ONION_KEY_TYPE                             [2 bytes]
+      ONION_KEY_TYPE                             [1 bytes]
       ONION_KEY                                  [depends on ONION_KEY_TYPE]
       NSPEC      (Number of link specifiers)     [1 byte]
       NSPEC times:
@@ -1458,8 +1469,10 @@ Status: Draft
    Substituting those fields into the INTRODUCE1 cell body format
    described in [FMT_INTRO1] above, we have
 
-            AUTH_KEYID                  [32 bytes]
-            ENC_KEYID                   [8 bytes]
+            AUTH_KEYTYPE                [1 byte]
+            AUTH_KEYID                  [depends on AUTH_KEYTYPE]
+            ENC_KEYTYPE                 [1 byte]
+            ENC_KEYID                   [depends on ENC_KEYTYPE]
             N_EXTENSIONS                [1 bytes]
             N_EXTENSIONS times:
                EXT_FIELD_TYPE           [1 byte]