Index: src/main/java/hudson/plugins/sshslaves/SSHLauncher.java
===================================================================
--- src/main/java/hudson/plugins/sshslaves/SSHLauncher.java	(revision 14803)
+++ src/main/java/hudson/plugins/sshslaves/SSHLauncher.java	(working copy)
@@ -12,6 +12,7 @@
 import org.kohsuke.stapler.DataBoundConstructor;
 
 import java.io.BufferedReader;
+import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.InputStreamReader;
@@ -48,6 +49,11 @@
     private final String password;
 
     /**
+     * Field privatekey
+     */
+    private final String privatekey;
+
+    /**
      * Field connection
      */
     private transient Connection connection;
@@ -64,13 +70,15 @@
      * @param port     The port to connect on.
      * @param username The username to connect as.
      * @param password The password to connect with.
+     * @param privatekey The ssh privatekey to connect with.
      */
     @DataBoundConstructor
-    public SSHLauncher(String host, int port, String username, String password) {
+    public SSHLauncher(String host, int port, String username, String password, String privatekey) {
         this.host = host;
         this.port = port == 0 ? 22 : port;
         this.username = username;
         this.password = password;
+        this.privatekey = privatekey;
     }
 
     /**
@@ -323,10 +331,19 @@
         connection.connect();
 
         // TODO if using a key file, use the key file instead of password
-        listener.getLogger().println(Messages.SSHLauncher_AuthenticatingUserPass(getTimestamp(), username, "******"));
-        boolean isAuthenicated = connection.authenticateWithPassword(username, password);
-
-        if (isAuthenicated && connection.isAuthenticationComplete()) {
+	boolean isAuthenticated = false;
+	if ( privatekey.length() > 0 ) {
+	    File key = new File(privatekey);
+	    if ( key.exists() ) {
+	        listener.getLogger().println(Messages.SSHLauncher_AuthenticatingPublicKey(getTimestamp(), username, privatekey));
+		isAuthenticated = connection.authenticateWithPublicKey(username, key, password);
+	    } 
+	}
+	if ( ! isAuthenticated ) {
+            listener.getLogger().println(Messages.SSHLauncher_AuthenticatingUserPass(getTimestamp(), username, "******"));
+	    isAuthenticated = connection.authenticateWithPassword(username, password);
+	}
+        if (isAuthenticated && connection.isAuthenticationComplete()) {
             listener.getLogger().println(Messages.SSHLauncher_AuthenticationSuccessful(getTimestamp()));
         } else {
             listener.getLogger().println(Messages.SSHLauncher_AuthenticationFailed(getTimestamp()));
@@ -403,6 +420,15 @@
     }
 
     /**
+     * Getter for property 'privatekey'.
+     *
+     * @return Value for property 'privatekey'.
+     */
+    public String getPrivatekey() {
+        return privatekey;
+    }
+
+    /**
      * {@inheritDoc}
      */
     public Descriptor<ComputerLauncher> getDescriptor() {
Index: src/main/resources/hudson/plugins/sshslaves/SSHLauncher/config.jelly
===================================================================
--- src/main/resources/hudson/plugins/sshslaves/SSHLauncher/config.jelly	(revision 14803)
+++ src/main/resources/hudson/plugins/sshslaves/SSHLauncher/config.jelly	(working copy)
@@ -9,10 +9,14 @@
     </f:entry>
 
     <f:advanced>
-        <f:entry title="${%Password}">
-            <input class="setting-input" type="password" name="launcher.password" value="${instance.password}"/>
+        <f:entry title="${%Password}" help="/plugin/ssh-slaves/help_password.html">
+            <input class="setting-input" type="password" name="launcher.password" value="${instance.password}" />
         </f:entry>
 
+        <f:entry title="${%Private Key File}" help="/plugin/ssh-slaves/help_privatekey.html">
+            <f:textbox name="launcher.privatekey" value="${instance.privatekey}"/>
+        </f:entry>
+
         <f:entry title="${%Port}">
             <f:textbox name="launcher.port" value="${h.ifThenElse(instance.port == null, '22', instance.port)}"/>
         </f:entry>
Index: src/main/resources/hudson/plugins/sshslaves/Messages.properties
===================================================================
--- src/main/resources/hudson/plugins/sshslaves/Messages.properties	(revision 14803)
+++ src/main/resources/hudson/plugins/sshslaves/Messages.properties	(working copy)
@@ -11,6 +11,7 @@
 SSHLauncher.NoJavaFound=Could not find a version of java that is at least version 1.5
 SSHLauncher.JavaVersionResult={0} [SSH] {1} -version returned {2}.
 SSHLauncher.OpeningSSHConnection={0} [SSH] Opening SSH connection to {1}.
+SSHLauncher.AuthenticatingPublicKey={0} [SSH] Authenticating as {1} with {2}.
 SSHLauncher.AuthenticatingUserPass={0} [SSH] Authenticating as {1}/{2}.
 SSHLauncher.AuthenticationSuccessful={0} [SSH] Authentication successful.
 SSHLauncher.AuthenticationFailed={0} [SSH] Authentication failed.
Index: src/main/webapp/help_password.html
===================================================================
--- src/main/webapp/help_password.html	(revision 0)
+++ src/main/webapp/help_password.html	(revision 0)
@@ -0,0 +1,6 @@
+<div>
+<p>This password will be used for both Public/Private Key authentication
+and Username/Password authentication.  If the SSH Private Key does not
+require a password, this field will be ignored (i.e. it is not an error
+to specify a password when none is needed).</p>
+</div>
Index: src/main/webapp/help_privatekey.html
===================================================================
--- src/main/webapp/help_privatekey.html	(revision 0)
+++ src/main/webapp/help_privatekey.html	(revision 0)
@@ -0,0 +1,8 @@
+<div>
+<p>This specifies the <b>absolute path</b> to the SSH private key file
+(e.g. <code>id_dsa</code> or <code>id_rsa</code>) to use for
+"password-less" Public/Private Key authentication.</p>
+
+<p>If this field is blank or if the Public/Private key authentication
+fails, the plugin will attempt username/password authentication.</p>
+</div>