Files
mailsender/README.md
T
Claude f63636f8f4 Add metrics, protected headers and pgpkeys actuator endpoint
- metrics (optional Micrometer): per-recipient outcome/policy/reason counter,
  refused counter, key lookup timer below the cache, cache size gauge
- SendReport.RecipientOutcome gains a structured PlaintextReason
- protected headers (RFC 9788, mail.pgp.protected-headers, off by default):
  real headers inside the encrypted part, outer Subject "[...]"
- encrypting keeps the caller's Message-ID
- pgpkeys endpoint (optional Actuator): inspect policy, lookup and key
  validity per address; evict one or all cached lookups
- KeyDiscoveryCustomizer and SecureMailSenderCustomizer extension points

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01G71TQ5jDETVwdUJxGAwaiT
2026-10-12 03:33:17 +00:00

77 lines
3.3 KiB
Markdown

# mailsender
OpenPGP encryption for Spring Boot mail: discovers recipients' keys via Web Key Directory (WKD) and sends
PGP/MIME (RFC 3156), or hands mail to an encrypting relay. See [docs/PLAN.md](docs/PLAN.md) for the design
and milestone status.
Requires JDK 27 and Maven 3.9+. Built on Spring Boot 4.1.1 and PGPainless 2.0.
```
mvn verify
```
## Modules
| Module | Contents |
|---|---|
| `mailsender-pgp-core` | WKD key discovery, caching, pinned keys, certificate validation, OpenPGP encryption, PGP/MIME (no Spring) |
| `mailsender-pgp-spring-boot-autoconfigure` | `mail.pgp.*` properties and beans |
| `mailsender-pgp-spring-boot-starter` | dependency bundle for applications |
| `mailsender-demo` | sample app that sends test mails |
## Usage
Add `pro.thinhha.mailsender:mailsender-pgp-spring-boot-starter`, configure `spring.mail.*` as usual, and send
through `SecureMailSender` instead of `JavaMailSender`:
```java
SendReport report = secureMailSender.send(message); // MimeMessage or SimpleMailMessage
```
Each recipient's key is looked up via WKD (cached) and validated. The message is then sent PGP/MIME-encrypted to
recipients with a usable key and in plaintext to the rest (logged as a downgrade), or refused with
`EncryptionPolicyException` if a `REQUIRE` recipient has no key. `SendReport` lists the outcome per recipient.
```yaml
mail:
pgp:
mode: BUILT_IN # or RELAY: hand plaintext to an encrypting gateway (mail.pgp.relay.*)
default-policy: OPPORTUNISTIC # REQUIRE | OPPORTUNISTIC | PLAINTEXT
mixed-mode: SPLIT # or FAIL
recipients:
"[*@partner.example]": REQUIRE
sender-keys: # your own PUBLIC key, so sent copies stay readable
"[noreply@example.com]": file:/etc/mail/noreply.pub.asc
```
Map keys that are addresses need the `[...]` brackets. See [docs/PLAN.md](docs/PLAN.md) for all options.
- `mail.pgp.protected-headers=true` encrypts the real Subject too (RFC 9788); the visible Subject becomes `[...]`.
- With Micrometer, `mail.pgp.recipients{outcome,policy,reason}`, `mail.pgp.refused`, `mail.pgp.key.lookup` and
`mail.pgp.key.cache.size` are recorded.
- With Actuator, expose `pgpkeys` to inspect an address (`GET /actuator/pgpkeys/{email}`) or evict cached keys
(`DELETE /actuator/pgpkeys/{email}`).
## Demo app
The demo app sends `DEMO_COUNT` test mails (default: 1 to `test@thinhha.pro`) through `SecureMailSender` and logs
the outcome per recipient: PGP/MIME-encrypted (RFC 3156) when a valid WKD key is found, otherwise plaintext.
Set `MAIL_PGP_MODE=RELAY` and `RELAY_HOST`/`RELAY_PORT`/`RELAY_USERNAME`/`RELAY_PASSWORD` to send via a gateway.
```
mvn -q install -DskipTests
SMTP_HOST=smtp.example.com SMTP_PORT=587 \
SMTP_USERNAME=me@example.com SMTP_PASSWORD='app-password' \
DEMO_TO=test@thinhha.pro DEMO_COUNT=1 \
java -jar mailsender-demo/target/mailsender-demo-0.1.0-SNAPSHOT.jar
```
| Variable | Default | Meaning |
|---|---|---|
| `SMTP_HOST` / `SMTP_PORT` | `localhost` / `587` | SMTP server |
| `SMTP_USERNAME` / `SMTP_PASSWORD` | empty | SMTP credentials |
| `SMTP_AUTH` / `SMTP_STARTTLS` | `true` / `true` | set to `false` for a local test server |
| `DEMO_TO` | `test@thinhha.pro` | recipient |
| `DEMO_FROM` | `SMTP_USERNAME` | sender address |
| `DEMO_COUNT` | `1` | number of mails |