From 8673e3c65797a72671fdf00932a0f13e43b62405 Mon Sep 17 00:00:00 2001
From: Heiko Schaefer <heiko@schaefer.name>
Date: Sat, 18 Nov 2023 22:54:24 +0100
Subject: [PATCH] packet dump of seipd v2 encrypted message

---
 book/source/21-zoom_encyption.md | 72 ++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)

diff --git a/book/source/21-zoom_encyption.md b/book/source/21-zoom_encyption.md
index 79880f2..831e57d 100644
--- a/book/source/21-zoom_encyption.md
+++ b/book/source/21-zoom_encyption.md
@@ -4,3 +4,75 @@ SPDX-License-Identifier: CC-BY-SA-4.0
 -->
 
 # Zooming in: Packet structure of encrypted data
+
+## SEIPD v2
+
+We encrypt a short message to Alice, using a public certificate version of {ref}`alice_priv`:
+
+```text
+$ echo "hello world" | sq encrypt --recipient-file alice.pub
+```
+
+This produces an ASCII armored encrypted message:
+
+```text
+-----BEGIN PGP MESSAGE-----
+
+wV0GIQbApYOEpDjloU9zcSQmpNRduu70o55rMLCdVRP5eKzKlBkxYaQzuusD78oj
+AdiGwQ8MI8sSAXAV4AEMKIcbINqhIBgSm5EV9h+Yl/XV3fEZ1JOaBnrtso2ZAS7S
+cgIHAQaWc/Ip4Thq0EZDZwlpRUk/TUL+TWEpsGdQs8ifDyFAk7t3+3XvvLr5dUg3
++Ot+sESkCSjhrZk50HIjwjBVZ6Y159yfaOqttMT6cXqWaxIishPaJ+OR1q2bZS1N
+2jFbaROOcbASK6AVzqCWneqkIA==
+=WFpq
+-----END PGP MESSAGE-----
+```
+
+Inspecting the packets of this message, we see:
+
+```text
+$ sq packet dump --hex enc.pgp
+Public-Key Encrypted Session Key Packet, new CTB, 2 header bytes + 93 bytes
+    Version: 6
+    Recipient: C0A58384A438E5A14F73712426A4D45DBAEEF4A39E6B30B09D5513F978ACCA94
+    Pk algo: X25519
+
+    00000000  c1                                                 CTB
+    00000001     5d                                              length
+    00000002        06                                           version
+    00000003           21                                        recipient_len
+    00000004              06                                     recipient_version
+    00000005                 c0 a5 83  84 a4 38 e5 a1 4f 73 71   recipient
+    00000010  24 26 a4 d4 5d ba ee f4  a3 9e 6b 30 b0 9d 55 13
+    00000020  f9 78 ac ca 94
+    00000025                 19                                  pk_algo
+    00000026                    31 61  a4 33 ba eb 03 ef ca 23   x25519_e
+    00000030  01 d8 86 c1 0f 0c 23 cb  12 01 70 15 e0 01 0c 28
+    00000040  87 1b 20 da a1 20
+    00000046                    18                               x25519_esk_len
+    00000047                       12  9b 91 15 f6 1f 98 97 f5   x25519_esk
+    00000050  d5 dd f1 19 d4 93 9a 06  7a ed b2 8d 99 01 2e
+
+Sym. Encrypted and Integrity Protected Data Packet, new CTB, 2 header bytes + 114 bytes
+    Version: 2
+    Symmetric algo: AES-128
+    AEAD algo: EAX
+    Chunk size: 4096
+    Salt: 9673F229E1386AD0464367096945493F4D42FE4D6129B06750B3C89F0F214093
+    No session key supplied
+
+    00000000  d2                                                 CTB
+    00000001     72                                              length
+    00000002        02                                           version
+    00000003           07                                        sym_algo
+    00000004              01                                     aead_algo
+    00000005                 06                                  chunk_size
+    00000006                    96 73  f2 29 e1 38 6a d0 46 43   salt
+    00000010  67 09 69 45 49 3f 4d 42  fe 4d 61 29 b0 67 50 b3
+    00000020  c8 9f 0f 21 40 93
+    00000026                    bb 77  fb 75 ef bc ba f9 75 48         .w.u....uH
+    00000030  37 f8 eb 7e b0 44 a4 09  28 e1 ad 99 39 d0 72 23   7..~.D..(...9.r#
+    00000040  c2 30 55 67 a6 35 e7 dc  9f 68 ea ad b4 c4 fa 71   .0Ug.5...h.....q
+    00000050  7a 96 6b 12 22 b2 13 da  27 e3 91 d6 ad 9b 65 2d   z.k."...'.....e-
+    00000060  4d da 31 5b 69 13 8e 71  b0 12 2b a0 15 ce a0 96   M.1[i..q..+.....
+    00000070  9d ea a4 20                                        ...
+```
\ No newline at end of file