Securing Traceability of Ciphertexts — Towards a Secure Software Key Escrow System

Desmedt, Yvo

doi:10.1007/3-540-49264-x_12

Cited by 31 publications

(16 citation statements)

References 19 publications

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“…The new GenState0 and RndQR algorithms are shown in Figure 5. The admissibility of proposed RndQR construction is confirmed by [10] and [26, §B.5.1.3], in the random oracle model.…”

Section: Implementing Sskgsmentioning

confidence: 65%

Practical Secure Logging: Seekable Sequential Key Generators

Marson

Poettering

2013

Lecture Notes in Computer Science

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Abstract. In computer forensics, log files are indispensable resources that support auditors in identifying and understanding system threats and security breaches. If such logs are recorded locally, i.e., stored on the monitored machine itself, the problem of log authentication arises: if a system intrusion takes place, the intruder might be able to manipulate the log entries and cover her traces. Mechanisms that cryptographically protect collected log messages from manipulation should ideally have two properties: they should be forward-secure (the adversary gets no advantage from learning current keys when aiming at forging past log entries), and they should be seekable (the auditor can verify the integrity of log entries in any order or access pattern, at virtually no computational cost). We propose a new cryptographic primitive, a seekable sequential key generator (SSKG), that combines these two properties and has direct application in secure logging. We rigorously formalize the required security properties and give a provably-secure construction based on the integer factorization problem. We further optimize the scheme in various ways, preparing it for real-world deployment. As a byproduct, we develop the notion of a shortcut one-way permutation (SCP), which might be of independent interest. Our work is highly relevant in practice. Indeed, our SSKG implementation has become part of the logging service of the systemd system manager, a core component of many modern commercial Linux-based operating systems.

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“…The new GenState0 and RndQR algorithms are shown in Figure 5. The admissibility of proposed RndQR construction is confirmed by [10] and [26, §B.5.1.3], in the random oracle model.…”

Section: Implementing Sskgsmentioning

confidence: 65%

Practical Secure Logging: Seekable Sequential Key Generators

Marson

Poettering

2013

Lecture Notes in Computer Science

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“…A common method (see [Des95,Sho05] and [NIS12, §B.5.1.3]) for sampling random elements x from Z n is to pick a seed r ← R {0, 1} and to output x = E(r). The resulting distribution is statistically close to uniform [Sho05].…”

Section: Discussionmentioning

confidence: 99%

Double-authentication-preventing signatures

Poettering

Stebila

2015

Int. J. Inf. Secur.

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Digital signatures are often used by trusted authorities to make unique bindings between a subject and a digital object; for example, certificate authorities certify a public key belongs to a domain name, and time-stamping authorities certify that a certain piece of information existed at a certain time. Traditional digital signature schemes however impose no uniqueness conditions, so a trusted authority could make multiple certifications for the same subject but different objects, be it intentionally, by accident, or following a (legal or illegal) coercion. We propose the notion of a double-authentication-preventing signature, in which a value to be signed is split into two parts: a subject and a message. If a signer ever signs two different messages for the same subject, enough information is revealed to allow anyone to compute valid signatures on behalf of the signer. This double-signature forgeability property discourages signers from misbehaving-a form of self-enforcement-and would give binding authorities like CAs some cryptographic arguments to resist legal coercion. We give a generic construction using a new type of trapdoor functions with extractability properties, which we show can be instantiated using the group of sign-agnostic quadratic residues modulo a Blum integer; we show an additional application of these new extractable trapdoor functions to standard digital signatures.

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“…One approach to anonymizing RSA, suggested by Desmedt [7], is to add random multiples of the modulus n to the ciphertext. This padding removes any information about the size of n and does not interfere with the reduction of the value modulo n. In the following, we assume that such a technique is adopted and that the adversary gains no information on the RSA modulus involved in some protocol (in a statistical sense) from the encoding used in the transcript.…”

Section: Ensuring That Handshakes Do Not Reveal the Groupmentioning

confidence: 99%

RSA-Based Secret Handshakes

Vergnaud

2006

Coding and Cryptography

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Abstract. A secret handshake mechanism allows two entities, members of a same group, to authenticate each other secretly. This primitive was introduced recently by Balfanz, Durfee, Shankar, Smetters, Staddon and Wong and, so far, all the schemes proposed are based on discrete log systems. This paper proposes three new secret handshake protocols secure against active impersonator and detector adversaries. Inspired by two RSA-based key agreement protocols introduced by Okamoto and Tanaka in 1989 and Girault in 1991, our schemes are, in the random oracle model, provably secure against active adversaries under the assumption that the RSA problem is intractable.

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Securing Traceability of Ciphertexts — Towards a Secure Software Key Escrow System

Cited by 31 publications

References 19 publications

Practical Secure Logging: Seekable Sequential Key Generators

Practical Secure Logging: Seekable Sequential Key Generators

Double-authentication-preventing signatures

RSA-Based Secret Handshakes

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