Protocols
=========


BlindTranspiler currently supports four delegated
blindness models.




BlindTranspiler currently supports multiple delegated
blindness models.

+----------+--------------+-------------+-------------------+------------------------+
| Protocol | Parametric   | Universal   | Data Blindness    | Compuation Blindness   |
+==========+==============+=============+===================+========================+
| QHE      | Yes          | Yes         | Yes               |  No                    |
+----------+--------------+-------------+-------------------+------------------------+
| UBQC     | Yes          | Yes         | Yes               |  Yes                   |
+----------+--------------+-------------+-------------------+------------------------+
| FDQC     | No           | Yes         | Yes               |  Yes                   |
+----------+--------------+-------------+-------------------+------------------------+
| SSDQC    | No           | Yes         | Yes               |  Yes                   |
+----------+--------------+-------------+-------------------+------------------------+


QHE
---


The ``QHE`` controller implements blind quantum
computation using Quantum Homomorphic Encryption (QHE)
based delegation techniques.

This controller converts quantum circuits into
half-blind delegated equivalents using homomorphic
translation rules.

The implementation follows:

* Childs (2005)
* Broadbent and Jeffery (2015)
* Fisher et al. (2014)
* Tan et al. (2017)
* Joshi et al. (2025)

Features:

* half-blind delegated computation
* arbitrary ``Rz`` support
* recursive decryption
* parametric gate delegation
* variational circuit compatibility

Suitable for:

* quantum homomorphic encryption
* variational quantum algorithms
* delegated parametric computation
* secure cloud quantum execution

See the detailed :doc:`controllers/qhe_controller` documentation:


UBQC
----


The ``UBQC`` controller implements Universal Blind
Quantum Computation using recursive decryption of
arbitrary rotations.


This controller enables efficient delegation of
parametric quantum circuits using universal
resource-set construction.

The implementation follows:

* Joshi et al. (2025)

Features:

* arbitrary-angle delegation
* recursive decryption
* low-depth blind transpilation
* optimized parametric delegation
* universal resource-set computation

See the detailed :doc:`controllers/ubqc_controller` documentation:


FDQC
----


The ``FDQC`` controller implements Full Delegated
Quantum Computation using ordered universal
resource sets.


This controller performs full-blind delegation using
ordered-set universal gate decomposition.

The implementation follows:

* Liu et al. (2020)

Features:

* universal blind computation
* ordered universal resource sets
* non-parametric delegation
* full-blind workflow
* reusable decryption primitives


See the detailed :doc:`controllers/fdqc_controller` documentation:


SSDQC
------


The ``SSDQC`` controller implements Single-Server
Delegated Quantum Computation using fixed-angle
rotation decomposition.


This controller performs blind delegation using
``π/4`` rotation equivalents and trap-based
universal delegation.

The implementation follows:

* Zhang et al. (2018)

Features:

* fixed-angle decomposition
* trap-based delegation
* universal gate replacement
* non-parametric blind computation


See the detailed :doc:`controllers/ssdqc_controller` documentation: