Public-key cryptography: Difference between revisions

Revision as of 16:52, 13 August 2025

Revision as of 00:00, 14 August 2025

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[[Non-repudiation]] systems use digital signatures to ensure that one party cannot successfully dispute its authorship of a document or communication.

Further applications built on this foundation include: [[digital cash]], [[password-authenticated key agreement]], [[Trusted timestamping|time-stamping services]] and non-repudiation protocols. Beyond traditional secure communication, public-key cryptography is fundamental to the operation of [[blockchain]] technologies and [[Cryptocurrency|cryptocurrencys]] like [[Bitcoin]] and [[Ethereum]]. It enables secure [[Digital signature|digital signatures]] for transactions, ensuring their authenticity and integrity without relying on a central authority. Additionally, it underpins secure access to cloud services, [[Virtual private network|virtual private networks]] (VPNs), and [[Internet of Things]] (IoT) devices, providing robust authentication and data encryption across diverse digital environments.

== Hybrid cryptosystems ==

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As with all security-related systems, there are various potential weaknesses in public-key cryptography. Aside from poor choice of an asymmetric key algorithm (there are few that are widely regarded as satisfactory) or too short a key length, the chief security risk is that the private key of a pair becomes known. All security of messages, authentication, etc., will then be lost.

Additionally, with the advent of [[quantum computing]], many asymmetric key algorithms are considered vulnerable to attacks, and new quantum-resistant schemes are being developed to overcome the problem.<ref>{{Cite journal |last1=Escribano Pablos |first1=José Ignacio |last2=González Vasco |first2=María Isabel |date=April 2023 |title=Secure post-quantum group key exchange: Implementing a solution based on Kyber |url=https://ietresearch.onlinelibrary.wiley.com/doi/10.1049/cmu2.12561 |journal=IET Communications |language=en |volume=17 |issue=6 |pages=758–773 |doi=10.1049/cmu2.12561 |hdl=10016/37141 |s2cid=255650398 |issn=1751-8628|hdl-access=free }}</ref><ref>{{Citation |last1=Stohrer |first1=Christian |title=Asymmetric Encryption |date=2023 |work=Trends in Data Protection and Encryption Technologies |pages=11–14 |editor-last=Mulder |editor-first=Valentin |place=Cham |publisher=Springer Nature Switzerland |language=en |doi=10.1007/978-3-031-33386-6_3 |isbn=978-3-031-33386-6 |last2=Lugrin |first2=Thomas |editor2-last=Mermoud |editor2-first=Alain |editor3-last=Lenders |editor3-first=Vincent |editor4-last=Tellenbach |editor4-first=Bernhard|doi-access=free }}</ref> The emergence of [[quantum computing]] poses a significant long-term threat to the security of many widely used public-key cryptographic algorithms, particularly [[RSA]] and [[Elliptic Curve Cryptography|ECC]]. These algorithms rely on the computational difficulty of factoring large numbers or solving discrete logarithms, problems that quantum computers could potentially solve efficiently using algorithms like [[Shor's algorithm]]. In response, the field of [[post-quantum cryptography]] is [https://www.ibm.com/think/topics/public-key-encryption actively researching and developing new cryptographic primitives that are resistant to attacks from both classical and quantum computers]. International efforts, such as those led by the [[National Institute of Standards and Technology]] (NIST), are [https://csrc.nist.gov/projects/post-quantum-cryptography underway to standardize these new algorithms for future secure communication].

=== Algorithms ===