International Association for Cryptologic Research

International Association
for Cryptologic Research

Transactions on Cryptographic Hardware and Embedded Systems 2025

KeyVisor – A Lightweight ISA Extension for Protected Key Handles with CPU-enforced Usage Policies


License

Copyright (c) 2022, Fabian Schwarz, Jan Philipp Thoma, Christian Rossow, Tim Güneysu, 
Ruhr-Universitaet Bochum and CISPA Helmholtz-Zentrum für Informationssicherheit

All rights reserved

This program is free software; You may use it or parts of it or modify it under the 
following terms:

(1) Usage and/or redistribution and/or modification of the software or parts of the
software is permitted for non-commercial use only.

(2a) If this software or parts are used as part of a new software, you must license
the entire work, as a whole, under this License to anyone who comes into possession
of a copy. This License will therefore apply, to the whole of the work, and all its
parts, regardless of how they are packaged.

(2b) You may expand this license by your own license. In this case this license still
applies to the software as mentioned in (2a) and must not be changed. The expansion
must be clearly recognizable as such. In any case of collision between the license
and the expansion the license is superior to the expansion.

(3) If this software or parts are used as part of a new software, you must provide
equivalent access to the source code of the entire work, as a whole, to anyone who
comes into possession of a copy, in the same way through the same place at no
further charge, as for the binary version.

(4) This program is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A 
PARTICULAR PURPOSE. 

(5) These notices must be retained in any copies of any part of this documentation
and/or software.

(6) If this software is used credit must be given to the "Chair for Security
Engineering, Ruhr-Universitaet Bochum, Germany and CISPA Helmholtz-Zentrum für
Informationssicherheit" as the authors of the parts of the software used. This can
be in the form of a textual message at program startup or at *beginning* of the
documentation (online or textual) provided with the package.

If you are interested in commercial use, please contact: `tim.gueneysu@rub.de` and
`rossow@cispa.de`