tcsd(8) daemon that manages Trusted Computing resources


tcsd [-f] [-e] [-c <configfile> ] [-h]


Trousers is an open-source TCG Software Stack (TSS), released under the BSD License. Trousers aims to be compliant with the current (1.1b) and upcoming (1.2) TSS specifications available from the Trusted Computing Group website:

tcsd is a user space daemon that should be (according to the TSS spec) the only portal to the TPM device driver. At boot time, tcsd should be started, it should open the TPM device driver and from that point on, all requests to the TPM should go through the TSS stack. The tcsd manages TPM resources and handles requests from TSP's both local and remote.

-f, --foreground
run the daemon in the foreground

attempt to connect to software TPMs over TCP

-c, --config <configfile>
use the provided configuration file rather than the default configuration file

-h, --help
display help message


There are two types of access control for the tcsd, access to the daemon's socket itself and access to specific commands internal to the tcsd. Access to the tcsd's port should be controlled by the system administrator using firewall rules. If using iptables, the following rule will allow a specific host access to the tcsd:

# iptables -A INPUT -s $IP_ADDRESS -p tcp --destination-port 30003 -j ACCEPT

Access to individual commands internal to the tcsd is configured by the tcsd configuration file's "remote_ops" directive. Each function call in the TCS API is reachable by a unique ordinal. Each labeled "remote op" actually defines a set of ordinals (usually more than one) necessary to accomplish the operation. So, for example, the "random" operation enables the ordinals for opening and closing a context, calling TCS_StirRandom and TCS_GetRandom, as well as TCS_FreeMemory. By default, connections from localhost will allow any ordinals.


TSS applications have access to 2 different kinds of 'persistent' storage. 'User' persistent storage has the lifetime of that of the application using it and therefore is destroyed when an application exits. User PS is controlled by the TSP of the application. 'System' persistent storage is controlled by the TCS and stays valid across application lifetimes, tcsd restarts and system resets. Data registered in system PS stays valid until an application requests that it be removed. User PS files are by default stored as /var/tpm/user.{pid} and the system PS file by default is /var/tpm/ The system PS file is initially created when ownership of the TPM is first taken.


tcsd configuration is stored by default in /etc/tcsd.conf


If TrouSerS has been compiled with debugging enabled, the debugging output can be supressed by setting the TSS_DEBUG_OFF environment variable.


tcsd is compatible with the IBM Research TPM device driver available from and the TPM device driver available from, which is also available in the upstream Linux kernel and many Linux distros.


tcsd conforms to the Trusted Computing Group Software Specification version 1.1 Golden


Kent Yoder


Report bugs to <[email protected]>