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edit next part of subkex binding signature

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Tammi L. Coles 2023-10-27 15:01:20 +02:00
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6
book/source/17-zoom_certificates.md
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@ -481,11 +481,11 @@ Signature Packet, new CTB, 2 header bytes + 171 bytes
000000a0 41 36 1b 2b 60 09 f2 d9 19 f4 41 12 0b
```
We'll go over this packet dump in less detail, since its structure mirrors the *Direct Key Signature* (described above) very closely.
The analysis of this packet dump will be less extensive, given that its structure mirrors the *Direct Key Signature* explored above.
The first difference is in the `type` field, showing that this signature is of type `0x18` ([Subkey Binding Signature](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-10.html#name-subkey-binding-signature-si)).
One notable difference is the `type` field, showing that this signature is of type `0x18` ([Subkey Binding Signature](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-10.html#name-subkey-binding-signature-si)).
The `pk_algo` of this signature is informed by the algorithm of the primary key (`0x1b`, corresponding to Ed25519). The signature in this packet is issued by the primary key, so by definition it uses the signing algorithm of the primary key (that is: the algorithm used to produce the cryptographic signature in this packet is entire independent of the `pk_algo` of the key material of this subkey itself, which uses the X25519 mechanism).
The `pk_algo` value of this signature derives from the algorithm of the primary key (`0x1b`, corresponding to Ed25519). This signature is issued by the primary key, thus using the signing algorithm of the primary key. (The algorithm used to produce the cryptographic signature in this packet is entirely independent of the `pk_algo` of the key material of this subkey itself, which uses the X25519 mechanism.)
As shown in the text at the top of this packet dump, the hashed subpacket data contains four pieces of information: