diff --git a/book/assets/drawio/prefixed-signed-message.drawio b/book/assets/drawio/prefixed-signed-message.drawio
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+++ b/book/assets/drawio/prefixed-signed-message.drawio
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diff --git a/book/assets/drawio/prefixed-signed-message.svg b/book/assets/drawio/prefixed-signed-message.svg
new file mode 100644
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--- /dev/null
+++ b/book/assets/drawio/prefixed-signed-message.svg
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\ No newline at end of file
diff --git a/book/source/signing_data.md b/book/source/signing_data.md
index 43cf0ed..4921348 100644
--- a/book/source/signing_data.md
+++ b/book/source/signing_data.md
@@ -76,7 +76,7 @@ A {term}`one-pass signed` {term}`OpenPGP message` consi
```{figure} plain_svg/ops-signed-message.svg
:name: fig-ops-signed-message
-:alt: Depicts the structure of a one-pass-signed message.
+:alt: Depicts the structure of a one-pass-signed message. Two one-pass-signatures lead the literal data packet, followed by two signature packets. Arrows show, how the hash-algorithm field of the one-pass-signatures is inspected in order to initiate the hashing procedure.
The structure of a one-pass signed message.
```
@@ -126,6 +126,13 @@ In this format, the signature packets are stored ahead of the message itself:
2. [**Literal data packet**](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` in this format, and the (otherwise equivalent) {term}`signature packet(s)` are stored ahead of the signed data.
For verification, this is equally convenient as the one-pass signed message form.