Keystone auth_token cache settings

service.conf

memcached_servers = 127.0.0.1
token_cache_time = 300
revocation_cache_time = 60

# if your memcached server is shared, use these settings to avoid cache poisoning
memcache_security_strategy = ENCRYPT
memcache_secret_key = <generate a secret key>

# if your keystone deployment uses PKI, and you value security over performance:
check_revocations_for_cached = true

# if your keystone deployment uses PKI and you're using a hashing algorithm other than MD5, specify it
hash_algorithms = sha256