[openpgp] [PATCH 2/3] Define AEAD mode for SKESK Packets

["brian m. carlson" <[e-mail]>]

---
 middle.mkd | 27 ++++++++++++++++++++++++---
 1 file changed, 24 insertions(+), 3 deletions(-)

diff --git a/middle.mkd b/middle.mkd
index 166b575..95ec44d 100644
--- a/middle.mkd
+++ b/middle.mkd
@@ -1735,10 +1735,9 @@ message to be encrypted to a number of public keys, and also to one or
 more passphrases.  This packet type is new and is not generated by
 PGP 2.x or PGP 5.0.
 
-The body of this packet consists of:
+A version 4 Symmetric-Key Encrypted Session Key packet consists of:
 
-  * A one-octet version number.  The only currently defined version
-    is 4.
+  * A one-octet version number with value 4.
 
   * A one-octet number describing the symmetric algorithm used.
 
@@ -1766,6 +1765,28 @@ specifier MUST use a salt value, either a Salted S2K or an
 Iterated-Salted S2K.  The salt value will ensure that the decryption
 key is not repeated even if the passphrase is reused.
 
+A version 5 Symmetric-Key Encrypted Session Key packet consists of:
+
+  * A one-octet version number with value 5.
+
+  * A one-octet cipher algorithm.
+
+  * A one-octet AEAD algorithm.
+
+  * A string-to-key (S2K) specifier, length as defined above.
+
+  * A starting initialization vector of size specified by the AEAD
+    algorithm.
+
+  * The encrypted session key itself, which is decrypted with the
+    string-to-key object using the given cipher and AEAD mode.
+
+  * A final, summary authentication tag for the AEAD mode.
+
+The encrypted session key is encrypted exactly as an AEAD Encrypted Data
+packet with a chunk size octet of 10 would be.  This implicit chunk size
+octet is included in the normal calculations of additional data.
+
 ## {5.4} One-Pass Signature Packets (Tag 4)
 
 The One-Pass Signature packet precedes the signed data and contains
-- 
2.14.0.rc0.284.gd933b75aa4