Handbook of Applied Cryptography - chap12

... use of number of ↓ Protocol timestamps messages point-to-point key update none optional 1-3 Shamir’s no-key protocol none no 3 Kerberos KDC yes 4 Needham-Schroeder shared-key KDC no 5 Otway-Rees ... possibility of precomputation to reduce on-line computational complexity. 6. third party requirements. Considerations include (see §13.2.4): (a) requirement of an on-line (real-time), of...

Ngày tải lên: 24/10/2013, 01:15

... problem of preserving the integrity of a potentially large message is thus reduced to that of a small fixed-size hash- value. Since the existence of collisions is guaranteed in many-to-one mappings, ... security of a subset of the MDCs subsequently discussed in this section. Similar to the case of block ciphers for encryption (e.g. 8- or 1 2- round DES vs. 16-round DES), se...

Ngày tải lên: 17/10/2013, 16:15

... attacks, 5 5 Both chosen-ciphertext and chosen-plaintext attacks are of concern for challenge-response techniques based on symmetric-key encryption. Handbook of Applied Cryptography by A. Menezes, ... entropy) Suppose passwords consist of strings of 7-bit ASCII char- acters. Each has a numeric value in the range 0-1 27. (When 8-bit characters are used, val- ues 12 8-2 55comp...

Ngày tải lên: 20/10/2013, 03:15

... while digital signatures with appendix are applied to messages of arbitrary length. The one-way function h in Algorithm 11.5 is Handbook of Applied Cryptography by A. Menezes, P. van Oorschot ... ratio of the logarithm(base2) of the size of the signingspaceM S to the logarithm (base 2) of the size of M R , the image space of the redundancy function. Hence, the bandwidt...

Ngày tải lên: 20/10/2013, 03:15

... protocol run (c) off-line on-line [optional] [optional] A A A in-line TTP TTP TTP off-line Figure 13.2: In-line, on-line, and off-line third parties. In-line third parties are of particular interest ... properties of escrow systems include: 1. applicability to store-and-forward vs. real-time user communications 2. capability of real-time decryption of user traffic 3. requirement of t...

Ngày tải lên: 28/10/2013, 09:15

... non-repudiation of origin (denial of being the originator of a message), non-repudiation of delivery (denial of having received a mes- sage), and non-repudiation associated with the actions of ... draft 10118–4 includes MASH-1 and MASH-2 (see Algorithm 9.56). ISO/IEC 11770: This multi-part standard addresses generic key management and spe- Handbook of Applied Cryptography...

Ngày tải lên: 28/10/2013, 09:15

... applications. The ef - ciency of a particular cryptographic scheme based on any one of these algebraic structures will dependonanumberoffactors, such as parametersize, time-memorytradeoffs,process- ing power ... the case of the additive group Z m , the time required to do modular multiplication can be im- proved at the expense of precomputing a table of residues modulo m. For a l...

Ngày tải lên: 06/11/2013, 23:15

... fac- tored is of a special form; these are called special-purpose factoring algorithms. The run- ning times of such algorithmstypically depend on certain properties of the factors of n. Ex- amples ... one having a worst-case running time of O(lg 3 n) bit operations, and a sec- ond having an average-case running time of O(lg 2 n) bit operations. A more recent algo- rithm of Berns...

Ngày tải lên: 14/12/2013, 00:22

Ngày tải lên: 16/01/2014, 16:33