Protecting against key-exposure: strongly key-insulated encryption with optimal threshold
Protecting against key-exposure: strongly key-insulated encryption with optimal threshold
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DOI：
10.1007/s00200-005-0183-y
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发表时间：
2005
期刊：
影响因子：
--
通讯作者：
M. Bellare;Adriana Palacio
中科院分区：
文献类型：
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作者：
M. Bellare;Adriana Palacio
密钥隔离加密方案结合使用密钥分割和密钥演化来防止密钥泄露。然而，现有方案的扩展性很差，其成本与可能被对手破坏的时间段的数量成正比，因此仅对于较小的值来说才实用。但实际上它可能很大。本文提出了一种具有最佳阈值的强密钥隔离加密方案。在我们的方案中，t不需要提前知道，并且可以大到比周期总数少一，但方案的成本不受影响。这使得密钥隔离加密更接近实践。我们的方案基于 Boneh-Franklin 基于身份的加密 (IBE) 方案 [9]，并利用了后者的代数属性。本文的另一个贡献是表明，具有最佳阈值并允许随机访问密钥更新（我们的方案和所有其他已知方案都允许）的（非强）密钥隔离加密等效于 IBE 的受限形式。这意味着密钥绝缘加密和 IBE 之间的联系并非偶然。
Key-insulated encryption schemes use a combination of key splitting and key evolution to protect against key exposure. Existing schemes, however scale poorly, having cost proportional to the numbertof time periods that may be compromised by the adversary, and thus are practical only for small values oft. Yet in practicetmight be large.This paper presents a strongly key-insulated encryption scheme withoptimal threshold. In our scheme,tneed not be known in advance and can be as large as one less than the total number of periods, yet the cost of the scheme is not impacted. This brings key-insulated encryption closer to practice. Our scheme is based on the Boneh-Franklin identity-based encryption (IBE) scheme [9], and exploits algebraic properties of the latter.Another contribution of this paper is to show that (not strongly) key-insulated encryption with optimal threshold and allowing random-access key updates (which our scheme and all others known allow) is equivalent to a restricted form of IBE. This means that the connection between key-insulated encryption and IBE is not accidental.