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Technical University of Munich
Picture of Bharath Purtipli

M.Sc. Bharath Purtipli

Technical University of Munich

Associate Professorship of Coding and Cryptography (Prof. Wachter-Zeh)

Postal address

Theresienstr. 90
80333 München

Biography

  • PhD student at the Chair of Communications Engineering at the Chair of Coding and Cryptography (Prof. Wachter-Zeh) since July 2025.
  • M.Sc. in Communications Engineering from the Technical University of Munich in June 2025.
  • B.Eng. in Electrical Engineering and Communications Engineering from PES University, Bengaluru in June 2019.

Research Interests

Lattice- and code-based cryptography: I am interested in the security and efficiency of post-quantum cryptographic schemes. Currently, I am working on improving the ciphertext length of the HQC cryptosystem.

Attribute-based encryption (ABE): Only a few code-based ABEs exist and it would be interesting to seek out the challenges in this field.

Theses

Available Theses

Theses in Progress

Attribute-based encryption

Description

In a public-key cryptosystem each user has an associated public key with which other users can send them an encrypted message. The correspondence between the user's identity and their public key is verified using certificates which are issued by some trusted authority.

Identity-based encryption (IBE) offers an alternate approach where one only needs the identity of the recipient to send them an encrypted message. The recipient then uses a secret key associated only with their identity to decrypt the message.

Attribute-based encryption (ABE) is a modification of the IBE setting for a system where users have attributes associated to them and a data owner wishes to send encrypted messages to subsets of users based on their attributes.

The goal of this seminar is to build up from the idea of an IBE proposed by Shamir in [1] on to the first paper on ABE by Sahai and Waters [2]. From there, two classes of ABEs are studied, namely ciphertext policy [3] and key policy ABEs [4].

[1] Shamir, A. (1985). Identity-Based Cryptosystems and Signature Schemes. In: Blakley, G.R., Chaum, D. (eds) Advances in Cryptology. CRYPTO 1984. Lecture Notes in Computer Science, vol 196. Springer, Berlin, Heidelberg. https://doi.org/10.1007/3-540-39568-7_5

[2] Sahai, A., Waters, B. (2005). Fuzzy Identity-Based Encryption. In: Cramer, R. (eds) Advances in Cryptology – EUROCRYPT 2005. EUROCRYPT 2005. Lecture Notes in Computer Science, vol 3494. Springer, Berlin, Heidelberg. https://doi.org/10.1007/11426639_27

[3] J. Bethencourt, A. Sahai and B. Waters, "Ciphertext-Policy Attribute-Based Encryption," 2007 IEEE Symposium on Security and Privacy (SP '07), Berkeley, CA, USA, 2007, pp. 321-334, doi: 10.1109/SP.2007.11.

[4] Vipul Goyal, Omkant Pandey, Amit Sahai, and Brent Waters. 2006. Attribute-based encryption for fine-grained access control of encrypted data. In Proceedings of the 13th ACM conference on Computer and communications security (CCS '06). Association for Computing Machinery, New York, NY, USA, 89–98. https://doi.org/10.1145/1180405.1180418

Supervisor:

Bharath Purtipli

Publications

2025

  • Purtipli, B.: HQC and Ciphertext Compression. Coding and Hiking, 2025 more… Full text (mediaTUM)
  • Purtipli, B.; Wachter-Zeh, A.: Sub-Project 4: Secure Transmission, Post-Quantum Crypto. 6G Future Lab Bavaria Kickoff, 2025 more… Full text (mediaTUM)
  • Purtipli, B.; Wachter-Zeh, A.: HQC and Ciphertext Quantization. 6G Future Lab Bavaria Speaker Series, 2025 more… Full text (mediaTUM)
  • Sebastian Bitzer, Emma Munisamy, Bharath Purtipli, Stefan Ritterhoff, Antonia Wachter-Zeh: Ciphertext Compression for HQC. Zürich PQC Workshop , 2025 more…
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