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114 lines
4.1 KiB
Markdown
114 lines
4.1 KiB
Markdown
<!--
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SPDX-FileCopyrightText: 2023 The "Notes on OpenPGP" project
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SPDX-License-Identifier: CC-BY-SA-4.0
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-->
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# Zooming in: Packet structure of encrypted data
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## SEIPD v2
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### Encrypt
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We encrypt a short message to Alice, using a public certificate version of {ref}`alice-priv`:
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```text
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$ echo "hello world" | sq encrypt --recipient-file alice.pub
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```
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This produces an ASCII armored encrypted message:
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```{literalinclude} ../examples/ascii_armored_encrypted_message.asc
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:language: text
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```
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### Inspect the packet dump of the encrypted message
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Inspecting the packets of this message, we see:
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```text
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$ sq packet dump --hex enc.pgp
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Public-Key Encrypted Session Key Packet, new CTB, 2 header bytes + 93 bytes
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Version: 6
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Recipient: C0A58384A438E5A14F73712426A4D45DBAEEF4A39E6B30B09D5513F978ACCA94
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Pk algo: X25519
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00000000 c1 CTB
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00000001 5d length
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00000002 06 version
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00000003 21 recipient_len
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00000004 06 recipient_version
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00000005 c0 a5 83 84 a4 38 e5 a1 4f 73 71 recipient
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00000010 24 26 a4 d4 5d ba ee f4 a3 9e 6b 30 b0 9d 55 13
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00000020 f9 78 ac ca 94
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00000025 19 pk_algo
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00000026 31 61 a4 33 ba eb 03 ef ca 23 x25519_e
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00000030 01 d8 86 c1 0f 0c 23 cb 12 01 70 15 e0 01 0c 28
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00000040 87 1b 20 da a1 20
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00000046 18 x25519_esk_len
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00000047 12 9b 91 15 f6 1f 98 97 f5 x25519_esk
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00000050 d5 dd f1 19 d4 93 9a 06 7a ed b2 8d 99 01 2e
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Sym. Encrypted and Integrity Protected Data Packet, new CTB, 2 header bytes + 114 bytes
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Version: 2
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Symmetric algo: AES-128
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AEAD algo: EAX
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Chunk size: 4096
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Salt: 9673F229E1386AD0464367096945493F4D42FE4D6129B06750B3C89F0F214093
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No session key supplied
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00000000 d2 CTB
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00000001 72 length
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00000002 02 version
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00000003 07 sym_algo
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00000004 01 aead_algo
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00000005 06 chunk_size
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00000006 96 73 f2 29 e1 38 6a d0 46 43 salt
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00000010 67 09 69 45 49 3f 4d 42 fe 4d 61 29 b0 67 50 b3
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00000020 c8 9f 0f 21 40 93
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00000026 bb 77 fb 75 ef bc ba f9 75 48 .w.u....uH
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00000030 37 f8 eb 7e b0 44 a4 09 28 e1 ad 99 39 d0 72 23 7..~.D..(...9.r#
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00000040 c2 30 55 67 a6 35 e7 dc 9f 68 ea ad b4 c4 fa 71 .0Ug.5...h.....q
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00000050 7a 96 6b 12 22 b2 13 da 27 e3 91 d6 ad 9b 65 2d z.k."...'.....e-
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00000060 4d da 31 5b 69 13 8e 71 b0 12 2b a0 15 ce a0 96 M.1[i..q..+.....
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00000070 9d ea a4 20 ...
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```
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### Decrypt
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```text
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$ sq decrypt --dump-session-key --recipient-file alice.sec enc.pgp
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Session key: 8DDA27B9B000BD84D0A39DFF66780111
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Encrypted using AES-128
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Compressed using ZIP
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hello world
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```
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Inspecting the packets inside the SEIPD container:
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```text
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$ sq decrypt --dump --recipient-file alice.sec enc.pgp
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Public-Key Encrypted Session Key Packet, new CTB, 93 bytes
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Version: 6
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Recipient: C0A58384A438E5A14F73712426A4D45DBAEEF4A39E6B30B09D5513F978ACCA94
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Pk algo: X25519
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Encrypted using AES-128
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Compressed using ZIP
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hello world
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Sym. Encrypted and Integrity Protected Data Packet, new CTB, 114 bytes
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│ Version: 2
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│ Symmetric algo: AES-128
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│ AEAD algo: EAX
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│ Chunk size: 4096
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│ Salt: 9673F229E1386AD0464367096945493F4D42FE4D6129B06750B3C89F0F214093
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│
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└── Compressed Data Packet, new CTB, 44 bytes
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│ Algorithm: ZIP
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│
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├── Literal Data Packet, new CTB, 18 bytes
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│ Format: Binary data
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│
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└── Padding Packet, new CTB, 14 bytes
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Unknown variant
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```
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