Move "nesting" section up into the OPS section

book/source/adv/signing_data.md

@@ -85,36 +85,7 @@ Strictly speaking, knowing just the hash algorithm would be sufficient to begin
 
 Important to note, the {term}`signer`'s {term}`public key<OpenPGP Certificate>`, critical for the final {term}`verification` step, is not embedded in the message. Verifiers must acquire this {term}`key` externally (e.g., from a {term}`key server`) to authenticate the {term}`signature<OpenPGP Signature Packet>` successfully.
 
-(prefixed-signature)=
+#### Nesting of one-pass signatures
-### Prefixed signed message
-
-A {term}`prefixed signed message` consists of {term}`signature packet(s)<signature packet>` followed by the message. For the verifier, processing one-pass signed and prefixed signed messages are equally convenient. However, on the signer's side, it takes more resources to generate a {term}`prefixed signed message`.
-
-#### Structure
-
-In this format, the signature packets are stored ahead of the message itself:
-
-1. **{term}`Data signature packets<OpenPGP Signature Packet>`**: These one or more packets contain the {term}`cryptographic signature` corresponding to the original data.
-
-2. [**{term}`OpenPGP message`**](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-12.html#lit): This contains the original data (e.g., the body of a message), without additional interpretation or conversion.
-
-```{figure} ../plain_svg/prefixed-signed-message.svg
-:name: fig-prefixed-signed-message
-:alt: Depicts the structure of a prefixed signed message. As an example, two signature packets lead a literal data packet. Arrows show, how the signatures hash algorithm field is inspected to start the hashing procedure.
-
-Structure of a prefixed signed message.
-```
-
-Compared to a {term}`one-pass signed message`, there are no {term}`one-pass signature packets<One-pass Signature Packet>` in this format, and the (otherwise equivalent) {term}`signature packet(s)<signature packet>` are stored ahead of the signed data.
-
-For verification, this is equally convenient as the one-pass signed message form.
-
-However, when a signer creates a {term}`prefixed signed message`, the signed data must be processed twice:
-
-- once reading it to calculate the cryptographic signature, and
-- once more to store the data in the generated OpenPGP message, after the signature packet(s).
-
-## Nesting of one-pass signatures
 
 Signing a message using the one-pass mechanism involves prepending a *one-pass signature* (OPS) packet to the message and appending the corresponding signature, sandwiching the signed content.
 
@@ -159,3 +130,32 @@ Now, a message, where the signer attests an already signed message has the follo
 `OPS₁ OPS₁ LIT("Hello World") SIG SIG`
 
 While the inner signature is calculated over the usual plaintext `Hello World`, the outer signature is instead calculated over `OPS₁ Hello World SIG`.
+
+(prefixed-signature)=
+### Prefixed signed message
+
+A {term}`prefixed signed message` consists of {term}`signature packet(s)<signature packet>` followed by the message. For the verifier, processing one-pass signed and prefixed signed messages are equally convenient. However, on the signer's side, it takes more resources to generate a {term}`prefixed signed message`.
+
+#### Structure
+
+In this format, the signature packets are stored ahead of the message itself:
+
+1. **{term}`Data signature packets<OpenPGP Signature Packet>`**: These one or more packets contain the {term}`cryptographic signature` corresponding to the original data.
+
+2. [**{term}`OpenPGP message`**](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-12.html#lit): This contains the original data (e.g., the body of a message), without additional interpretation or conversion.
+
+```{figure} ../plain_svg/prefixed-signed-message.svg
+:name: fig-prefixed-signed-message
+:alt: Depicts the structure of a prefixed signed message. As an example, two signature packets lead a literal data packet. Arrows show, how the signatures hash algorithm field is inspected to start the hashing procedure.
+
+Structure of a prefixed signed message.
+```
+
+Compared to a {term}`one-pass signed message`, there are no {term}`one-pass signature packets<One-pass Signature Packet>` in this format, and the (otherwise equivalent) {term}`signature packet(s)<signature packet>` are stored ahead of the signed data.
+
+For verification, this is equally convenient as the one-pass signed message form.
+
+However, when a signer creates a {term}`prefixed signed message`, the signed data must be processed twice:
+
+- once reading it to calculate the cryptographic signature, and
+- once more to store the data in the generated OpenPGP message, after the signature packet(s).