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Provable Security

Bizonyított biztonság
A tantárgyleírás hatályossága
Hatályosság kezdete:
2026. March 21.
Hatályosság vége:
Subject name (Hungarian, English)
Bizonyított biztonság
Provable Security
Subject code BMEVIHID022
Subject type
Training Level
Course types and hours (weekly/semester)
Course type lecture tutorial laboratory
hours (weekly) 4 0 0
type (linked/independent)
Assessment type vizsga
Credits 5
Subject coordinator
Dr.Vajda István
Responsible department
Hálózati Rendszerek és Szolgáltatások Tanszék
Faculty Villamosmérnöki és Informatikai Kar
Subject website
Primary curriculum type
Direct prerequisites – Strong prerequisite none
Direct prerequisites – Weak prerequisite none
Direct prerequisites – Parallel prerequisite none
Direct prerequisites – Milestone prerequisite none
Direct prerequisites – Exclusion none

Objectives

Programme
1. week:  Paradigms in provable security:  Algorithmic reduction, algorithmic indistinguishability, simulatability.  Security by indistingushability (security game) vs. security by simulation of ideal functionality.
2. week: Standard secure cryptographic primitives: Public key encryption: semantic security, message-indistinguishability (IND-CPA, IND-CCA2), non-malleability. Digital signature. Message authentication.
3. week: Standard secure cryptographic protocols: Stand-alone setting. GMW oblivious transfer protocol. Fiat-Shamir party authentication protocol.
4. week: Secure Multiparty Computation. Secure function evaluation.
5. week: Universal composability (UC): Modular composition. Concurrent setting. UC-security vs. non-concurent (stand-alone) security.
6. week: Models in the UC security framework: Computational model. Model of protocol execution. Bare model. Plain model. Trusted setups and trusted third parties.  Adversarial models. Hybrid protocol.
7-10. week: Ideal functionalities and trusted setup models in the UC:  Authenticated communication. Secure communication channel. Key exchange. Public key encryption. Digital signature. Commitment. Oblivious transfer. Remote coin tossing.  Zero knowledge proofs (ZKP). Secure function evaluation.  The Common Reference String and Key setup models.
11. week: The UC composition theorem.
12. week: UC with joint state (JUC).
13. week: Realizability issues in the UC framework.
14. week: Protocol applications: E-voting, E-auction.  

This subject provides an introduction into the techniques of constructions of cryptographic primitives and protocols with formally provable security guarantees. In contrast to ad-hoc approaches in the usual practice.

Learning outcomes

Ez a tantárgy a KKK rendeletben meghatározott, következő kompetenciák fejlesztését szolgálja:

Knowledge

No learning outcomes recorded.

Skills

No learning outcomes recorded.

Attitudes

No learning outcomes recorded.

Autonomy and responsibility

No learning outcomes recorded.

Oktatási módszertan

lectures with plenty of analysis/construction examples

Tanulástámogató anyagok

Online források
- Goldreich: Foundations of Cryptography, Cambridge Press, 2004; - R.Canetti: Universally Composable Security: A New Paradigm for Cryptographic Protocols, 2005; - presentation slides

Recommended preliminary knowledge for completing the subject

Knowledge type competencies
(azon előzetes ismeretek összessége, amelyek megléte nem kötelező, de a tantárgy eredményes teljesítését nagyban elősegíti)
MSc level knowledge in Discrete Mathematics, Probability Theory and in Theory of Algorithms
Skill type competencies
(azon előzetes képességek és készségek összessége, amelyek megléte nem kötelező, de a tantárgy eredményes teljesítését nagyban elősegíti)
nincs
Recommended (non-compulsory) preliminary competencies
(azon ajánlott (nem kötelező) előzetesen megszerzendő kompetenciák összessége, amelyek jelentősen hozzájárulnak a tantárgy eredményes teljesítéséhez)
MSc level knowledge in Discrete Mathematics, Probability Theory and in Theory of Algorithms
General rules
Requirements: a. During the semester: One in-class test (ZH) in the second half of the semester. Condition for the signature is the pass mark of ZH test (40% above). There is a possibility to rewrite the in-class test (ZH). In the rectification period (repeat period) there is another (final) possibility to rewrite the in-class test (ZH). b. Examination: Oral exam.
Assessment methods
In-term assessments

No detailed assessments provided.

Weight of in-term assessments

No weights provided.

Exam-period assessments

No detailed assessments provided.

Weight of exam elements

No weights provided.

Grade calculation

No grade thresholds provided.

Attendance requirements

No attendance requirements provided.

Rules for retake and resubmission

Not provided.

Short description

Not provided.

Detailed description

Not provided.

Recommended courses

Not provided.

Workload to complete the subject

No workload breakdown provided.

Validity of subject requirements
Requirements valid from:
Requirements valid until:
Curriculum placement

No curriculum placements recorded for this subject version.