diff --git a/scripts/ssh/ssh-auth.php b/scripts/ssh/ssh-auth.php
--- a/scripts/ssh/ssh-auth.php
+++ b/scripts/ssh/ssh-auth.php
@@ -4,74 +4,84 @@
 $root = dirname(dirname(dirname(__FILE__)));
 require_once $root.'/scripts/__init_script__.php';
 
-$keys = id(new PhabricatorAuthSSHKeyQuery())
-  ->setViewer(PhabricatorUser::getOmnipotentUser())
-  ->withIsActive(true)
-  ->execute();
-
-if (!$keys) {
-  echo pht('No keys found.')."\n";
-  exit(1);
-}
+$cache = PhabricatorCaches::getMutableCache();
+$authfile_key = PhabricatorAuthSSHKeyQuery::AUTHFILE_CACHEKEY;
+$authfile = $cache->getKey($authfile_key);
+
+if ($authfile === null) {
+  $keys = id(new PhabricatorAuthSSHKeyQuery())
+    ->setViewer(PhabricatorUser::getOmnipotentUser())
+    ->withIsActive(true)
+    ->execute();
+
+  if (!$keys) {
+    echo pht('No keys found.')."\n";
+    exit(1);
+  }
 
-$bin = $root.'/bin/ssh-exec';
-foreach ($keys as $ssh_key) {
-  $key_argv = array();
-  $object = $ssh_key->getObject();
-  if ($object instanceof PhabricatorUser) {
-    $key_argv[] = '--phabricator-ssh-user';
-    $key_argv[] = $object->getUsername();
-  } else if ($object instanceof AlmanacDevice) {
-    if (!$ssh_key->getIsTrusted()) {
-      // If this key is not a trusted device key, don't allow SSH
-      // authentication.
+  $bin = $root.'/bin/ssh-exec';
+  foreach ($keys as $ssh_key) {
+    $key_argv = array();
+    $object = $ssh_key->getObject();
+    if ($object instanceof PhabricatorUser) {
+      $key_argv[] = '--phabricator-ssh-user';
+      $key_argv[] = $object->getUsername();
+    } else if ($object instanceof AlmanacDevice) {
+      if (!$ssh_key->getIsTrusted()) {
+        // If this key is not a trusted device key, don't allow SSH
+        // authentication.
+        continue;
+      }
+      $key_argv[] = '--phabricator-ssh-device';
+      $key_argv[] = $object->getName();
+    } else {
+      // We don't know what sort of key this is; don't permit SSH auth.
       continue;
     }
-    $key_argv[] = '--phabricator-ssh-device';
-    $key_argv[] = $object->getName();
-  } else {
-    // We don't know what sort of key this is; don't permit SSH auth.
-    continue;
-  }
 
-  $key_argv[] = '--phabricator-ssh-key';
-  $key_argv[] = $ssh_key->getID();
+    $key_argv[] = '--phabricator-ssh-key';
+    $key_argv[] = $ssh_key->getID();
 
-  $cmd = csprintf('%s %Ls', $bin, $key_argv);
+    $cmd = csprintf('%s %Ls', $bin, $key_argv);
 
-  $instance = PhabricatorEnv::getEnvConfig('cluster.instance');
-  if (strlen($instance)) {
-    $cmd = csprintf('PHABRICATOR_INSTANCE=%s %C', $instance, $cmd);
-  }
+    $instance = PhabricatorEnv::getEnvConfig('cluster.instance');
+    if (strlen($instance)) {
+      $cmd = csprintf('PHABRICATOR_INSTANCE=%s %C', $instance, $cmd);
+    }
 
-  // This is additional escaping for the SSH 'command="..."' string.
-  $cmd = addcslashes($cmd, '"\\');
+    // This is additional escaping for the SSH 'command="..."' string.
+    $cmd = addcslashes($cmd, '"\\');
 
-  // Strip out newlines and other nonsense from the key type and key body.
+    // Strip out newlines and other nonsense from the key type and key body.
 
-  $type = $ssh_key->getKeyType();
-  $type = preg_replace('@[\x00-\x20]+@', '', $type);
-  if (!strlen($type)) {
-    continue;
-  }
+    $type = $ssh_key->getKeyType();
+    $type = preg_replace('@[\x00-\x20]+@', '', $type);
+    if (!strlen($type)) {
+      continue;
+    }
 
-  $key = $ssh_key->getKeyBody();
-  $key = preg_replace('@[\x00-\x20]+@', '', $key);
-  if (!strlen($key)) {
-    continue;
-  }
+    $key = $ssh_key->getKeyBody();
+    $key = preg_replace('@[\x00-\x20]+@', '', $key);
+    if (!strlen($key)) {
+      continue;
+    }
+
+    $options = array(
+      'command="'.$cmd.'"',
+      'no-port-forwarding',
+      'no-X11-forwarding',
+      'no-agent-forwarding',
+      'no-pty',
+    );
+    $options = implode(',', $options);
 
-  $options = array(
-    'command="'.$cmd.'"',
-    'no-port-forwarding',
-    'no-X11-forwarding',
-    'no-agent-forwarding',
-    'no-pty',
-  );
-  $options = implode(',', $options);
+    $lines[] = $options.' '.$type.' '.$key."\n";
+  }
 
-  $lines[] = $options.' '.$type.' '.$key."\n";
+  $authfile = implode('', $lines);
+  $ttl = phutil_units('24 hours in seconds');
+  $cache->setKey($authfile_key, $authfile, $ttl);
 }
 
-echo implode('', $lines);
+echo $authfile;
 exit(0);
diff --git a/src/applications/auth/editor/PhabricatorAuthSSHKeyEditor.php b/src/applications/auth/editor/PhabricatorAuthSSHKeyEditor.php
--- a/src/applications/auth/editor/PhabricatorAuthSSHKeyEditor.php
+++ b/src/applications/auth/editor/PhabricatorAuthSSHKeyEditor.php
@@ -191,6 +191,20 @@
     return 'ssh-key-'.$object->getPHID();
   }
 
+  protected function applyFinalEffects(
+    PhabricatorLiskDAO $object,
+    array $xactions) {
+
+    // After making any change to an SSH key, drop the authfile cache so it
+    // is regenerated the next time anyone authenticates.
+    $cache = PhabricatorCaches::getMutableCache();
+    $authfile_key = PhabricatorAuthSSHKeyQuery::AUTHFILE_CACHEKEY;
+    $cache->deleteKey($authfile_key);
+
+    return $xactions;
+  }
+
+
   protected function getMailTo(PhabricatorLiskDAO $object) {
     return $object->getObject()->getSSHKeyNotifyPHIDs();
   }
diff --git a/src/applications/auth/query/PhabricatorAuthSSHKeyQuery.php b/src/applications/auth/query/PhabricatorAuthSSHKeyQuery.php
--- a/src/applications/auth/query/PhabricatorAuthSSHKeyQuery.php
+++ b/src/applications/auth/query/PhabricatorAuthSSHKeyQuery.php
@@ -3,6 +3,8 @@
 final class PhabricatorAuthSSHKeyQuery
   extends PhabricatorCursorPagedPolicyAwareQuery {
 
+  const AUTHFILE_CACHEKEY = 'ssh.authfile';
+
   private $ids;
   private $phids;
   private $objectPHIDs;
diff --git a/src/applications/cache/PhabricatorCaches.php b/src/applications/cache/PhabricatorCaches.php
--- a/src/applications/cache/PhabricatorCaches.php
+++ b/src/applications/cache/PhabricatorCaches.php
@@ -99,6 +99,23 @@
     return $caches;
   }
 
+  public static function getMutableCache() {
+    static $cache;
+    if (!$cache) {
+      $caches = self::buildMutableCaches();
+      $cache = self::newStackFromCaches($caches);
+    }
+    return $cache;
+  }
+
+  private static function buildMutableCaches() {
+    $caches = array();
+
+    $caches[] = new PhabricatorKeyValueDatabaseCache();
+
+    return $caches;
+  }
+
 
 /* -(  Repository Graph Cache  )--------------------------------------------- */
 
diff --git a/src/applications/cache/PhabricatorKeyValueDatabaseCache.php b/src/applications/cache/PhabricatorKeyValueDatabaseCache.php
--- a/src/applications/cache/PhabricatorKeyValueDatabaseCache.php
+++ b/src/applications/cache/PhabricatorKeyValueDatabaseCache.php
@@ -98,7 +98,7 @@
         $this->establishConnection('w'),
         'DELETE FROM %T WHERE cacheKeyHash IN (%Ls)',
         $this->getTableName(),
-        $keys);
+        $map);
     }
 
     return $this;