Add age key

- Add AGE.md with policies
- Add age-recipient.txt for `age -R`
- Add ceremonies/2026-09-13_age_key.md as the signed record
  of which recipient is valid from which date
- List the recipient in KEYS.md
- Describe AGE.md and age-recipient.txt in README.md
- Extend the scripts:
  + sign.sh signs AGE.md by default
  + verify.sh verifies AGE.md by default
    and cross-checks age-recipient.txt,
    the only unsigned artifact,
    against the recipient in the signed KEYS.md and AGE.md

AGE.md

@@ -0,0 +1,61 @@
+# `age` Key Documentation
+
+This document specifies how I maintain my [age](https://github.com/FiloSottile/age) key.
+
+It is (re-)signed with the current OpenPGP key:
+
+```bash
+./scripts/sign.sh AGE.md  # to produce AGE.md.asc
+
+gpg --verify AGE.md.asc AGE.md
+```
+
+
+## Current Key
+
+> `age1gzy6tj8y93ljuelcedrkcsv3p6gygk7ng3386u32av9a4ujh737qef8crp`
+
+| Field    | Value                                      |
+|----------|--------------------------------------------|
+| Type     | X25519 (native age identity)               |
+| Created  | 2026-09-11                                 |
+| Expires  | never (because `age` has no expiry)        |
+| Deployed | all machines, `~/.config/age/identity.txt` |
+
+
+### Policies
+
+- One identity on all machines,
+  like the OpenPGP `[E]` subkey
+- No expiry and no revocation:
+  Rotation means replacing the key
+  in this file, in [`KEYS.md`](KEYS.md), and in [`age-recipient.txt`](age-recipient.txt),
+  recording it in [`ceremonies/`](ceremonies/),
+  running `./scripts/sign.sh` to re-sign the signed documents, and
+  encrypting anything that matters again
+- The OpenPGP signature on this file is the trust anchor;
+  [`age-recipient.txt`](age-recipient.txt) is a convenience copy for `age -R`
+
+
+### Storage
+
+- Secret key: In my **Vaultwarden** as secure note "age Identity"
+  (because they are offline-synced text, unlike attachments)
+- Public record: **This repository**
+  - [`AGE.md`](AGE.md)
+  - [`age-recipient.txt`](age-recipient.txt)
+- Distribution: My **public websites**
+  - [alexander-hess.com](https://www.alexander-hess.com/age-recipient.txt)
+    ([Policies](https://www.alexander-hess.com/AGE.md),
+     [Signature](https://www.alexander-hess.com/AGE.md.asc))
+  - [webartifex.de](https://www.webartifex.de/age-recipient.txt)
+    ([Policies](https://www.webartifex.de/AGE.md),
+     [Signature](https://www.webartifex.de/AGE.md.asc))
+
+
+## Ceremonies
+
+- Introduction of this key:
+  [`ceremonies/2026-09-13_age_key.md`](ceremonies/2026-09-13_age_key.md)
+- A future rotation gets its own record in [`ceremonies/`](ceremonies/),
+  signed with the OpenPGP key of that day

AGE.md.asc

@@ -0,0 +1,7 @@
+-----BEGIN PGP SIGNATURE-----
+
+iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCaqcVTQAKCRC0bttN/CaA
+XVAsAP9aX22LadD4EXK7i9Oe+omWg2Yn3+WBtQT6WSL+17rD+gD+O7xVv25MZR4d
+/AlJLAha+YG4705KWrRSZEbSm/9zkwQ=
+=GjG6
+-----END PGP SIGNATURE-----

KEYS.md

@@ -23,3 +23,14 @@ Fingerprint:
 Armored export: [`public-key.asc`](public-key.asc)
 
 For policies, ceremonies, and history, see: [`OPENPGP.md`](OPENPGP.md)
+
+
+## `age`
+
+Recipient:
+
+> `age1gzy6tj8y93ljuelcedrkcsv3p6gygk7ng3386u32av9a4ujh737qef8crp`
+
+Recipient file: [`age-recipient.txt`](age-recipient.txt)
+
+For policies, see: [`AGE.md`](AGE.md)

KEYS.md.asc

@@ -1,7 +1,7 @@
 -----BEGIN PGP SIGNATURE-----
 
-iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCaqcTMgAKCRC0bttN/CaA
+iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCaqcTZwAKCRC0bttN/CaA
-XQsIAQCbVwRUzKeoM3OMJlSbGq4bpuSDmWXGPo/s5KbJlMEkNAEA1gVHfRpomGwL
+XXb9AQCw+qK35dxdRK6s/HWGMBPYiR8yB416TKU0kabgOYcfngEA4wFrDQLEmcla
-coNc4VC9qDwk5wdpis+NDRNtpIOIqgs=
+1e86A8GM2CiFGKIYUJ6rts/V6Oxt9Qk=
-=quB1
+=GQGh
 -----END PGP SIGNATURE-----

OPENPGP.md

@@ -66,7 +66,7 @@ gpg --verify OPENPGP.md.asc OPENPGP.md
     for convenient usage,
     refreshed by `scripts/snapshot.sh`
   - `ceremonies/`, signed records of exceptional events,
-    such as the 2026 supersession
+    such as the 2026 supersession and the `age` key introduction
   - `history/`, armored exports of all retired keys,
     see [Key History](#key-history) below
   - `snapshots/<KEYID>-public-YYYY.asc`,

OPENPGP.md.asc

@@ -1,7 +1,7 @@
 -----BEGIN PGP SIGNATURE-----
 
-iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCarGC1AAKCRC0bttN/CaA
+iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCarGC7QAKCRC0bttN/CaA
-XS5IAQDcDzL+O2P0LvrrDvTiLPme2mcyAifUCbCCNSnHXjzerQEA5TAwKK0ktW29
+XRhgAP9JASLtDJi1M6m8uskF8IfxHw/4uUmP/bnSB5HeXfFNKwEAk17jzrsNYcfb
-7yDzIi4T+uQ0kAttq91U6oIT8Wzb1QM=
+1HVZlJi3G9WRpA3NzEe9nP6QVxWuows=
-=VAgU
+=ot15
 -----END PGP SIGNATURE-----

README.md

@@ -38,6 +38,7 @@ gpg --import public-key.asc
 
 gpg --verify KEYS.md.asc KEYS.md
 gpg --verify OPENPGP.md.asc OPENPGP.md
+gpg --verify AGE.md.asc AGE.md
 ```
 
 Each `gpg --verify` will print two things:
@@ -96,6 +97,22 @@ How I implement [OpenPGP](https://www.openpgp.org/):
   Armored public keys of all previous OpenPGP keys
 
 
+### `age`
+
+Besides OpenPGP,
+    I also use the modern [`age`](https://github.com/FiloSottile/age) encryption:
+
+- [`AGE.md`](AGE.md):
+  `age` policies
+- [`AGE.md.asc`](AGE.md.asc):
+  Detached signature, renewed at every ceremony
+- [`age-recipient.txt`](age-recipient.txt):
+  `age` public key for `age -R`
+- [`ceremonies/`](ceremonies/):
+  Signed record of when a recipient became valid or rotated
+  because `age` keys carry no metadata of their own
+
+
 ### Scripts
 
 `sh` scripts for my own use:
@@ -107,7 +124,8 @@ How I implement [OpenPGP](https://www.openpgp.org/):
   Renews the detached signatures
 - [`verify.sh`](scripts/verify.sh):
   Verifies all signed files against the pinned signing subkey,
-  and warns when the key is about to expire
+  warns when the key is about to expire, and
+  cross-checks `age-recipient.txt`
 - [`snapshot.sh`](scripts/snapshot.sh):
   Exports the current key to `snapshots/` and `public-key.asc`
 - [`publish.sh`](scripts/publish.sh):

age-recipient.txt

@@ -0,0 +1 @@
+age1gzy6tj8y93ljuelcedrkcsv3p6gygk7ng3386u32av9a4ujh737qef8crp

ceremonies/2026-09-13_age_key.md

@@ -0,0 +1,25 @@
+# New `age` Key
+
+Effective as of 2026-09-13,
+    I publish an `age` identity next to my OpenPGP key:
+
+```
+age1gzy6tj8y93ljuelcedrkcsv3p6gygk7ng3386u32av9a4ujh737qef8crp
+```
+
+Type X25519, created 2026-09-11, no expiry and no revocation.
+
+No OpenPGP key material changed in this ceremony.
+`AGE.md` was added, `KEYS.md` gained the recipient,
+    and all detached signatures were renewed.
+
+Because `age` recipients carry no metadata,
+    this signed record is the only proof
+    of which recipient was valid from which date.
+
+A future rotation gets its own record here,
+    superseding this one.
+
+The policies are in [`AGE.md`](../AGE.md).
+
+This file is signed with the current OpenPGP key.

ceremonies/2026-09-13_age_key.md.asc

@@ -0,0 +1,7 @@
+-----BEGIN PGP SIGNATURE-----
+
+iHUEABYKAB0WIQTW0Zid8fayP9d2KT20bttN/CaAXQUCaqcOrAAKCRC0bttN/CaA
+Xaj9AQD+Wwuxhlserdi+HGO5XJabm4xCEcVqCQid+zQctG97hQEAxBBSzzL6yNwG
+4pHqSmaMUvJkIkSSBH4ERxSsGvvjGw4=
+=h7yN
+-----END PGP SIGNATURE-----

scripts/sign.sh

@@ -4,7 +4,7 @@
 #
 # Usage:  ./scripts/sign.sh [FILE...]
 #
-# FILE defaults to KEYS.md OPENPGP.md
+# FILE defaults to KEYS.md OPENPGP.md AGE.md
 #
 # Writes FILE.asc next to each FILE and verifies it
 
@@ -22,6 +22,7 @@ if [ $# -eq 0 ]; then
     set -- \
         "$REPO/KEYS.md" \
         "$REPO/OPENPGP.md" \
+        "$REPO/AGE.md" \
         # Keep this list aligned with the documentation at the top
 fi
 

scripts/verify.sh

@@ -4,15 +4,17 @@
 #
 # Usage:  ./scripts/verify.sh [FILE...]
 #
-# FILE defaults to KEYS.md OPENPGP.md ceremonies/*.md
+# FILE defaults to KEYS.md OPENPGP.md ceremonies/*.md AGE.md
 #
 # A FILE with a FILE.asc next to it is checked as a detached signature,
 # any other FILE as a clearsigned document
 #
-# Also checks the key's expiry
+# Also checks the key's expiry, and,
+# if KEYS.md or AGE.md is among the FILEs,
+# that age-recipient.txt matches the recipient in them
 #
 # Exits non-zero if any file lacks a valid signature from the pinned key,
-# or if the key has expired
+# or if the key has expired, or if a cross-check fails
 
 set -eu
 
@@ -33,6 +35,7 @@ if [ $# -eq 0 ]; then
         "$REPO/KEYS.md" \
         "$REPO/OPENPGP.md" \
         "$REPO"/ceremonies/*.md \
+        "$REPO/AGE.md" \
         # Keep this list aligned with the documentation at the top
 fi
 
@@ -100,4 +103,26 @@ else
 fi
 
 
+# age-recipient.txt is the only unsigned artifact,
+# so it must match the recipient in the signed documents
+for FILE; do
+
+    case "$FILE" in
+        */KEYS.md | KEYS.md | */AGE.md | AGE.md)
+            # shellcheck disable=SC2016  # The backticks are literal Markdown
+            EXPECTED=$(sed -n 's/^> `\(age1[0-9a-z]*\)`$/\1/p' "$FILE")
+            ACTUAL=$(cat "$REPO/age-recipient.txt")
+            if [ -z "$EXPECTED" ]; then
+                echo "FAIL  No age recipient found in $FILE" >&2
+                FAILED=1
+            elif [ "$ACTUAL" != "$EXPECTED" ]; then
+                echo "FAIL  age-recipient.txt has $ACTUAL, $FILE has $EXPECTED" >&2
+                FAILED=1
+            fi
+            ;;
+    esac
+
+done
+
+
 exit "$FAILED"