Brent Waters’s research while affiliated with University of Texas at Austin and other places

... • Constructions of ABE from null-iO/WE seem to require embedding some form of obfuscation of the access policy in the ciphertext, leading to non-compact ciphertexts, i.e. ciphertext size is dependent on policy size. Explicit constructions of ABE from WE seem to appear only recently [FWW23], which built registered-ABE (RABE) and broadcast encryption (BE) from WE. Indeed, their RABE has non-compact ciphertexts due to the aforementioned obstacle, and the techniques they used for building BE do not seem to translate to an ABE for circuits. In contrast, [Wee22] and our schemes achieve compact ciphertexts. ...

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Lattice-based Multi-Authority/Client Attribute-based Encryption for Circuits

... In the Feature Articles in this issue, the research lab directors explain the aims of their respective laboratories [2][3][4]. In addition, Brent Waters, a distinguished scientist in the area of basic cryptography theory, shares his thoughts on creating a new research lab [5]. ...

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NTT Research, Inc. Launched to Strengthen and Globalize R&D

... As such many pairing-based schemes (e.g. [LW11,DKW23a,DKW23b,AG23], see also [DKW23b, Table 1]) can be interpreted as MA-ABE for NC1 circuits. ...

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Lattice-based Multi-Authority/Client Attribute-based Encryption for Circuits

... An alternative option based on early encoding leverages attribute-based encryption (ABE) [25,40]. In an ABE scheme, each participant receives a secret key linked to some attributes (e.g., geographical location), while ciphertexts are linked to policies. ...

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Secure Computation and Trustless Data Intermediaries in Data Spaces

... As such many pairing-based schemes (e.g. [LW11,DKW23a,DKW23b,AG23], see also [DKW23b, Table 1]) can be interpreted as MA-ABE for NC1 circuits. ...

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Lattice-based Multi-Authority/Client Attribute-based Encryption for Circuits

... We need to show that for any set of ciphertexts and any decryption key the probability that the evaluation of the decryption key, associated with a function , on the set of ciphertexts outputs ( ) + with the same probability that was sampled over Δ. schemes relies on the hardness of the general -Linear assumption [41], being still the basis of various state-of-the-art papers, e.g., [46]. It works for any choice of , including the Symmetric External Diffie-Hellman Assumption (SXDH) for = 1 and the Decisional Linear Assumption (DLIN) for = 2. ...

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Differentially Private Functional Encryption

... Tracing vs. Watermarking. Goyal et al. [GKWW21] argue that watermarking PRFs are too weak for traitor-tracing applications since programs can easily be useful without retaining input-output behaviour on a large fraction of the input, e.g. by recovering only half of the output value, or when used as subroutines, e.g. as part of a decryption program. In these cases, the watermarking authority may not be able to extract the mark from a forged program, since extraction is only guaranteed if given complete and correct outputs of the PRF. ...

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Simple Watermarking Pseudorandom Functions from Extractable Pseudorandom Generators

... All pairing-based cryptographic constructions are vulnerable against quantum adversaries. Currently, all plausibly post-quantum secure candidates are lattice-based, including the schemes of [DKW21,WWW22], and ours. We summarise existing lattice-based MA-ABEs in Table 1, where we also include the state-of-the-art group-based scheme of [DKW23b] for comparison. ...

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Lattice-based Multi-Authority/Client Attribute-based Encryption for Circuits

... In the construction, we set p D ‚.2 / and dim.s/ to a large enough polynomial in . tions imply a vast array of cryptographic objects, so much so that iO has been conjectured to be a "central hub" [71,92] for cryptography. ...

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Indistinguishability obfuscation

... Instantiations. Compute and compare obfuscators with almost perfect correctness are constructed in [GKW17,WZ17] based on quantum LWE, and recently with perfect correctness in [GKVW19] based on quantum LWE. ...

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Post-Quantum Multi-Party Computation in Constant Rounds