Disable hardcoded Let's Encrypt server certificate

acme4j-client/src/main/java/org/shredzone/acme4j/provider/letsencrypt/LetsEncryptAcmeProvider.java

@@ -20,6 +20,8 @@ import org.shredzone.acme4j.connector.HttpConnector;
 import org.shredzone.acme4j.exception.AcmeProtocolException;
 import org.shredzone.acme4j.provider.AbstractAcmeProvider;
 import org.shredzone.acme4j.provider.AcmeProvider;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
 
 /**
  * An {@link AcmeProvider} for <em>Let's Encrypt</em>.
@@ -27,13 +29,14 @@ import org.shredzone.acme4j.provider.AcmeProvider;
  * The {@code serverUri} is {@code "acme://letsencrypt.org"} for the production server,
  * and {@code "acme://letsencrypt.org/staging"} for a testing server.
  * <p>
- * If you want to use <em>Let's Encrypt</em>, always prefer to use this provider, as it
- * takes care for the correct connection and SSL certificates.
+ * If you want to use <em>Let's Encrypt</em>, always prefer to use this provider.
  *
  * @see <a href="https://letsencrypt.org/">Let's Encrypt</a>
  */
 public class LetsEncryptAcmeProvider extends AbstractAcmeProvider {
 
+    private static final Logger LOG = LoggerFactory.getLogger(LetsEncryptAcmeProvider.class);
+
     private static final String V01_DIRECTORY_URI = "https://acme-v01.api.letsencrypt.org/directory";
     private static final String STAGING_DIRECTORY_URI = "https://acme-staging.api.letsencrypt.org/directory";
 
@@ -63,8 +66,14 @@ public class LetsEncryptAcmeProvider extends AbstractAcmeProvider {
     }
 
     @Override
+    @SuppressWarnings("deprecation")
     protected HttpConnector createHttpConnector() {
+        if (Boolean.getBoolean("acme4j.le.certfix")) {
+            LOG.warn("Using a hardcoded Let's Encrypt certificate. It will expire by June 2018.");
             return new LetsEncryptHttpConnector();
+        } else {
+            return super.createHttpConnector();
+        }
     }
 
 }

acme4j-client/src/main/java/org/shredzone/acme4j/provider/letsencrypt/LetsEncryptHttpConnector.java

@@ -32,7 +32,11 @@ import org.shredzone.acme4j.connector.HttpConnector;
 /**
  * {@link HttpConnector} to be used for Let's Encrypt. It is pinned to the Let's Encrypt
  * server certificate.
+ *
+ * @deprecated API server certificate CA is accepted by current JREs. There is no need
+ * for certificate pinning any more. Hardcoded certificate will expire by June 25th, 2018.
  */
+@Deprecated
 public class LetsEncryptHttpConnector extends HttpConnector {
 
     private static SSLSocketFactory sslSocketFactory;

src/site/markdown/ca/letsencrypt.md

@@ -8,13 +8,9 @@ Web site: [Let's Encrypt](https://letsencrypt.org)
 * `acme://letsencrypt.org/staging` - Testing server
 * `acme://letsencrypt.org/v01` - Production server, pinned to API v01
 
-## Features
+## Compatibility
 
-* Accepts the ACME server certificate of Let's Encrypt even on older Java versions
-
-## Note
-
-* _Let's Encrypt_ diverges from the ACME specifications for various reasons. For this reason, some parts of the _acme4j_ API may not behave as documented. [See here for more details.](https://github.com/letsencrypt/boulder/blob/master/docs/acme-divergences.md)
+If you have to use a Java version that is older than 8u101 and does not accept the _IdenTrust_ certificates of the _Let's Encrypt_ servers, you can use a hardcoded local truststore as a workaround by setting the `acme4j.le.certfix` system property to `true`. Please note that the hardwired certificate will expire by June, 2018.
 
 ## Limits
 

src/site/markdown/migration.md

@@ -2,6 +2,12 @@
 
 This document will help you migrate your code to the latest _acme4j_ version.
 
+## Migration to Version 0.12
+
+Java support for the _IdenTrust_ certificate that is used by _Let's Encrypt_ servers was added to JRE 8u101 in July 2016. For this reason, _acme4j_ does not need to use a hardcoded local truststore anymore. It has been disabled in this version, and the standard Java truststore is used instead.
+
+If you have to use an older JRE, you can re-enable the local truststore by setting the `acme4j.le.certfix` system property to `true`. Please note that the local certificate will expire by June, 2018.
+
 ## Migration to Version 0.10
 
 Starting with version 0.10, _acme4j_ requires Java 8 or higher. This is also reflected in the API.