Horizone Keystone Unable to communicate with identity service Unable to sign token

Log from Horizon
-----------------------
DEBUG:openstack_auth.backend:Beginning user authentication for user "admin".
DEBUG:openstack_auth.backend:Authorization Failed: Unable to communicate with identity service: {"error": {"message": "Unable to sign token.", "code": 500, "title": "Internal Server Error"}}. (HTTP 500)
[02/May/2013 12:17:25] "POST /auth/login/ HTTP/1.1" 200 4453
[02/May/2013 12:17:25] "GET /i18n/js/horizon/ HTTP/1.1" 200 2158

Log from Keystone
-------------------------
2013-05-02 17:45:59    ERROR [keystone.common.cms] Signing error: Unable to load certificate - ensure you've configured PKI with 'keystone-manage pki_setup'
2013-05-02 17:45:59  WARNING [keystone.common.wsgi] Unable to sign token.

Solution
-----------
#cd install_dir/keystone
#source .venv/bin/activate

#./bin/keystone-manage pki_setup

#sudo chown saju:root -R /etc/keystone/ssl/

#./bin/keystone-all