Time-Based Release of Confidential Information in Hierarchical Settings

Nali, Deholo; Adams, Carlisle; Miri, Ali

doi:10.1007/11556992_3

Cited by 6 publications

(4 citation statements)

References 12 publications

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“…Specifically, the schemes of [4] and [23] use the tree-like structure of [6] backwards, to construct previous trapdoors, while [8] uses an inverted hash chain, similarly to the S/Key system [15]. These approaches have a high communication cost, while the root of the tree-like structure and the hash chain, respectively, correspond to the last available trapdoor to be published, implying an upper bound on the "lifetime" of the system.…”

Section: Introductionmentioning

confidence: 99%

Low-cost Anonymous Timed-Release Encryption

Hristu-Varsakelis¹,

Chalkias²,

Stephanides³

2007

Third International Symposium on Information Assurance and Security

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We propose a new server-based efficient protocol for time-release encryption (TRE), or -as sometimes referred to -sending information "into the future". As with other recently-proposed schemes, ours is based on the use of bilinear pairings on any Gap Diffie-Hellman group, allowing absolute release time of the encrypted data. Our protocol possesses the required properties regarding user anonymity and server passivity. It also provides almost-costless scalability in settings with multiple time-servers, and improves significantly upon existing TRE schemes, in terms of computational and communication cost. This makes our approach well-suited to a number of emerging e-applications that require future decryption of confidential data.

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Section: Introductionmentioning

confidence: 99%

Low-cost Anonymous Timed-Release Encryption

Hristu-Varsakelis¹,

Chalkias²,

Stephanides³

2007

Third International Symposium on Information Assurance and Security

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“…The same situation applies for rapid dissemination of freshly published, crucial or highly priced, and formerly secret information [18], such as stock market values, strategic business plans, news agencies timed publications, licensed software updates, etc. Considering the size of the confidential information is significantly larger than the size of an encryption key (which is often the case), timely distribution of information to a large and distributed community of users is often impeded by network traffic jams.…”

Section: More Applicationsmentioning

confidence: 98%

“…no communication is needed between the agent and other entities. Many applications of TRE are discussed [5,6,10,17,18]. For examples, [10] talks about asking a broker to sell a stock at a particular future time, and [17] gives an application in certified email system.…”

Section: Timed-release Encryptionmentioning

confidence: 99%

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Token-Controlled Public Key Encryption in the Standard Model

Chow

Lecture Notes in Computer Science

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In many financial or legal scenarios (such as trading stocks, wills and safe-deposit boxes), we want to ensure that a certain task (reading the buy/sell instruction, obtaining the property, or opening the box in emergencies respectively) cannot be performed until a certain time or a certain pre-defined condition occurs. Token-controlled public key encryption (TCE), introduced in [2], is a handy tool for these situations. Roughly speaking, messages are encrypted by a public key together with a secret token in TCE, such that the receiver holding the corresponding private key cannot decrypt until the token is released. TCE is also useful in rapid distribution of information and sealed-bid auctions, etc.In Financial Cryptography 2006, Galindo and Herranz [15] proposed a generic construction of TCE in the random oracle model. However, we show that it is insecure against insider attack, namely, a malicious user without the token can learn partial information about the message.We propose a strengthened definition of security, and also new privacy requirements. It turns out that [15] is also insecure against outsider attack in our new definition. We then give a new generic construction provably secure in the standard model, which is nearly as efficient as a standard public key encryption scheme.

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