1 files changed, 47 insertions, 0 deletions
diff --git a/sshlib/src/main/java/com/trilead/ssh2/ExtendedServerHostKeyVerifier.java b/sshlib/src/main/java/com/trilead/ssh2/ExtendedServerHostKeyVerifier.java
new file mode 100644
index 0000000..f757aa6
--- /dev/null
+++ b/sshlib/src/main/java/com/trilead/ssh2/ExtendedServerHostKeyVerifier.java
@@ -0,0 +1,47 @@
+package com.trilead.ssh2;
+
+import java.util.List;
+
+/**
+ * This extends the {@link ServerHostKeyVerifier} interface by allowing the remote server to indicate it has multiple
+ * server key algorithms available. After authentication, the {@link #getKnownKeyAlgorithmsForHost(String, int)} method
+ * may be called and compared against the list of server-controller keys. If a key algorithm has been added then
+ * {@link #addServerHostKey(String, int, String, byte[])} will be called. If a key algorithm has been removed, then
+ * {@link #removeServerHostKey(String, int, String, byte[])} will be called.
+ *
+ * @author Kenny Root
+ */
+public abstract class ExtendedServerHostKeyVerifier implements ServerHostKeyVerifier {
+	/**
+	 * Called during connection to determine which keys are known for this host.
+	 *
+	 * @param hostname the hostname used to create the {@link Connection} object
+	 * @param port the server's remote TCP port
+	 * @return list of hostkey algorithms for the given <code>hostname</code> and <code>port</code> combination
+	 * 			or {@code null} if none are known.
+	 */
+	public abstract List<String> getKnownKeyAlgorithmsForHost(String hostname, int port);
+
+	/**
+	 * After authentication, if the server indicates it no longer uses this key, this method will be called
+	 * for the app to remove its record of it.
+	 *
+	 * @param hostname the hostname used to create the {@link Connection} object
+	 * @param port the server's remote TCP port
+	 * @param serverHostKeyAlgorithm key algorithm of removed key
+	 * @param serverHostKey key data of removed key
+	 */
+	public abstract void removeServerHostKey(String hostname, int port, String serverHostKeyAlgorithm,
+			byte[] serverHostKey);
+
+	/**
+	 * After authentication, if the server indicates it has another <code>keyAlgorithm</code>, this method will be
+	 * called for the app to add it to its record of known keys for this <code>hostname</code>.
+	 *
+	 * @param hostname the hostname used to create the {@link Connection} object
+	 * @param port the server's remote TCP port
+	 * @param keyAlgorithm SSH standard name for the key to be added
+	 * @param serverHostKey SSH encoding of the key data for the key to be added
+	 */
+	public abstract void addServerHostKey(String hostname, int port, String keyAlgorithm, byte[] serverHostKey);
+}