Differentiate inline-signed messages between one-pass-signed and prefix-signed messages

book/source/signing_data.md

@@ -54,7 +54,12 @@ This method is commonly used for signing or encrypting emails. Most email softwa
 
 #### Structure
 
-An {term}`inline-signed<Inline Signature>` {term}`OpenPGP message` consists of three segments:
+There are two different constructions available to generate inline-signed messages:
+
+* {term}`One-pass-signed messages<One-pass-signed Message>` are signed using one ore more {term}`one-pass signatures<One-pass Signature Packet>` 
+* {term}`Prefixed-signed messages<Prefixed-signed Message>` have the actual signature(s) prefixed to the {term}`OpenPGP message<OpenPGP Message>`.
+
+A {term}`one-pass-signed<One-pass-signed Message>` {term}`OpenPGP message` consists of three segments:
 
 1. [**One-pass signature packets**](https://www.ietf.org/archive/id/draft-ietf-openpgp-crypto-refresh-12.html#one-pass-sig): These one or more {term}`packets<Packet>` precede the signed data and enable {term}`signature<OpenPGP Signature Packet>` computation in one pass.
 
@@ -62,6 +67,8 @@ An {term}`inline-signed<Inline Signature>` {term}`OpenPGP message` consists of t
 
 3. **{term}`Data signature packets<OpenPGP Signature Packet>`**: These contain the {term}`cryptographic signature` corresponding to the original data.
 
+Less commonly used are {term}`prefixed-signed messages<Prefixed-signed Message>`, where the {term}`signature packet(s)<signature packet>` are simply prepended to the message.
+
 #### Creation
 
 To produce an {term}`inline signature`, the {term}`signer` processes the entirety of the data by reading from an input file and writing into an output {term}`OpenPGP message` file. As the data is processed, the {term}`signer` simultaneously calculates a {term}`cryptographic signature`. This procedure results in the appending of a {term}`data signature packet` to the output {term}`OpenPGP message` file, where it can be efficiently stored.