A Timed-Release Key Management Scheme for Backward Recovery
A Timed-Release Key Management Scheme for Backward Recovery
复制标题
DOI：
10.1007/11734727_3
复制
发表时间：
2005-12
期刊：
影响因子：
--
通讯作者：
Maki Yoshida;S. Mitsunari;T. Fujiwara
中科院分区：
文献类型：
--
作者：
Maki Yoshida;S. Mitsunari;T. Fujiwara
定时释放加密方案是对消息进行加密，以便在未来特定时间到来时可以解密密文。最近，人们提出了一些有趣的构造定时释放加密方案的方法。这种结构的中心概念是一个公共代理，它周期性地广播自认证的时间信息，称为时间令牌。时间令牌包含绝对时间信息，例如“格林威治时间2005年12月1日08：09”。发送方对消息进行加密，从而密文的接收方可以根据指定发布时间的时间令牌生成解密密钥。虽然这种构造具有许多优点，但由于时间令牌只能用于计算相应时间的解密密钥，因此对丢失时间令牌的弹性仍然不能令人满意。一种有希望的方法是构造解密密钥，使得不仅可以根据相应的时间令牌而且可以根据稍后时刻(例如，08：10 AM、08：11 AM等)的解密密钥来计算解密密钥(例如，08：09 AM)。实现这种向后恢复的一种简单结构是使用构成散列链的密钥来加密消息，并通过使用定时释放加密方案来加密这些密钥。这种构造很简单，但需要加密的开销。为了减少开销，本文引入了一种定时释放密钥管理方案，该方案将解密密钥关联起来，从而提供了后发性。其特点是发送者可以自由、灵活地选择解密密钥具有倒排性的时刻。本文还给出了一种基于双线性映射的有效构造方法。
The timed-release encryption scheme is to encrypt a message so that a ciphertext can be decrypted when specific time in the future comes. Recently, interesting constructions of the timed-release encryption scheme have been proposed. The central concept of the constructions is a public agent which periodically broadcasts self-authenticated time information, called a time token. A time token contains absolute time information such as “08:09AM Dec. 1, 2005 GMT.” A sender encrypts a message so that a receiver of the ciphertext can generate a decryption key from a time token of the designated release time. Although the constructions have many advantages, resilience to missing time tokens is not still satisfactory since a time token can be used only for computing a decryption key of the corresponding time. A promising approach is to construct decryption keys so that a decryption key (e.g., of 08:09AM) can be computed not only from the corresponding time token but also from decryption keys of later time instants (e.g., 08:10AM, 08:11AM and so on). A trivial construction to realize such backward recovery is to use keys, which constitute a hash chain, for encrypting messages and encrypt these keys by using the timed-release encryption scheme. This construction is simple but requires the overhead of encryption. To reduce the overhead, this paper introduces a timed-release key management scheme in which decryption keys are related so that the backward property is provided. The feature is that a sender can choose freely and flexibly the time instants of which decryption keys have the backward property. The paper also gives an efficient construction based on a bilinear map.