寻求有关加密解密算法RC5的资料，急用！！！
谢绝大段DES描述！
希望提供有关RC5算法的有关资料，对算法以及代码的说明，中英文的都好，最好是中英文对照的材料，不知所云的不给分，回答不错的必给高分！
请在此回答或发信箱（信箱不保险，上次有人发信到我信箱没有收到）！
谢谢大家帮助。
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问题点数：100、回复次数：5Top
1 楼moonmistake（）回复于 2002-06-15 21:48:11 得分 15
http://xexploit.css.com.cn/aqjs/content/mimajishu/14rc5jy.htm
http://www.programsalon.com/download.asp?type_id=35&pos=20 (这里有算法代码）
http://go7.163.com/keyes/component.html （(这里有算法代码）
http://yxme.net/encrypt_src/source_algo_cipher_c.htm（这里有算法代码）
估计这些够你用的
http://www.google.com/search?q=RC5%E7%AE%97%E6%B3%95&hl=zh-CN&lr=lang_zh-CN&ie=UTF8&oe=UTF8&start=20&sa=NTop
2 楼ebingku（阿炳酷）回复于 2002-06-16 02:55:58 得分 0
谢谢，希望能提供些算法的说明，我有算法了Top
3 楼moonmistake（）回复于 2002-06-16 09:02:42 得分 15
http://www.copathway.com/itbookreview/view_paper.asp?paper_id=24
这个是关于算法说明的 或许对你有帮助Top
4 楼yrwithsh（清脆的杯子）回复于 2002-06-16 09:52:00 得分 20
10. Security Considerations
The RC5 cipher is relatively new so critical reviews are still being performed. However, the cipher's simple structure makes it easy to analyze and hopefully easier to assess its strength. Reviews so far are very promising.
Early results [1] suggest that for RC5 with a 64 bit block size (32 bit word size), 12 rounds will suffice to resist linear and differential cyptanalysis. The 128 bit block version has not been studied as much as the 64 bit version, but it appears that 16 rounds would be an appropriate minimum. Block sizes less than 64 bits are academically interesting but should not be used for cryptographic security. Greater security can be achieved by increasing the number of rounds at the cost of decreasing the throughput of the cipher.
Baldwin & Rivest Informational [Page 26]
RFC 2040 RC5, RC5-CBC, RC5-CBC-Pad, and RC5-CTS October 1996
The length of the secret key helps determine the cipher's resistance to brute force key searching attacks. A key length of 128 bits should give adequate protection against brute force key searching by a well funded opponent for a couple decades [7]. For RC5 with 12 rounds, the key setup time and data encryption time are the same for all key lengths less than 832 bits, so there is no performance reason for choosing short keys. For larger keys, the key expansion step will run slower because the user key table, L, will be longer than the expanded key table, S. However, the encryption time will be unchanged since it is only a function of the number of rounds.
To comply with export regulations it may be necessary to choose keys that only have 40 unknown bits. A poor way to do this would be to choose a simple 5 byte key. This should be avoided because it would be easy for an opponent to pre-compute key searching information.
Another common mechanism is to pick a 128 bit key and publish the first 88 bits. This method reveals a large number of the entries in the user key table, L, and the question of whether RC5 key expansion provides adequate security in this situation has not been studied, though it may be fine. A conservative way to conform to a 40 bit limitation is to pick a seed value of 128 bits, publish 88 bits of this seed, run the entire seed through a hash function like MD5 [4], and use the 128 bit output of the hash function as the RC5 key.
In the case of 40 unknown key bits with 88 known key bits (i.e., 88 salt bits) there should still be 12 or more rounds for the 64 bit block version of RC5, otherwise the value of adding salt bits to the key is likely to be lost.
The lifetime of the key also influences security. For high security applications, the key to any 64 bit block cipher should be changed after encrypting 2**32 blocks (2**64 blocks for a 128 bit block cipher). This helps to guard against linear and differential cryptanalysis. For the case of 64 bit blocks, this rule would recommend changing the key after 2**40 (i.e. 10**12) bytes are encrypted. See Schneier [6] page 183 for further discussion.
Baldwin & Rivest Informational [Page 27]
RFC 2040 RC5, RC5-CBC, RC5-CBC-Pad, and RC5-CTS October 1996
11. ASN.1 Identifiers
For applications that use ASN.1 descriptions, it is necessary to define the algorithm identifier for these ciphers along with their parameter block formats. The ASN.1 definition of an algorithm identifier already exists and is listed below for reference.
AlgorithmIdentifier ::= SEQUENCE {
algorithm OBJECT IDENTIFIER,
parameters ANY DEFINED BY algorithm OPTIONAL
}
The values for the algorithm field are:
RC5_CBC OBJECT IDENTIFIER ::=
{ iso (1) member-body (2) US (840) rsadsi (113549)
encryptionAlgorithm (3) RC5CBC (8) }
RC5_CBC_Pad OBJECT IDENTIFIER ::=
{ iso (1) member-body (2) US (840) rsadsi (113549)
encryptionAlgorithm (3) RC5CBCPAD (9) }
The structure of the parameters field for these algorithms is given below. NOTE: if the iv field is not included, then the initialization vector defaults to a block of zeros whose size depends on the blockSizeInBits field.
RC5_CBC_Parameters ::= SEQUENCE {
version INTEGER (v1_0(16)),
rounds INTEGER (8..127),
blockSizeInBits INTEGER (64, 128),
iv OCTET STRING OPTIONAL
}
References
[1] Kaliski, Burton S., and Yinqun Lisa Yin, "On Differential and Linear Cryptanalysis of the RC5 Encryption Algorithm", In Advances in Cryptology - Crypto '95, pages 171-184, Springer-Verlag, New York, 1995.
[2] Rivest, Ronald L., "The RC5 Encryption Algorithm", In Proceedings of the Second International Workshop on Fast Software Encryption, pages 86-96, Leuven Belgium, December 1994.
[3] Rivest, Ronald L., "RC5 Encryption Algorithm", In Dr. Dobbs Journal, number 226, pages 146-148, January 1995.
Baldwin & Rivest Informational [Page 28]
RFC 2040 RC5, RC5-CBC, RC5-CBC-Pad, and RC5-CTS October 1996
[4] Rivest, Ronald L., "The MD5 Message-Digest Algorithm", RFC 1321.
[5] RSA Laboratories, "Public Key Cryptography Standards (PKCS)", RSA Data Security Inc. See ftp.rsa.com.
[6] Schneier, Bruce, "Applied Cryptography", Second Edition, John Wiley and Sons, New York, 1996. Errata: on page 195, line 13, the reference number should be [402]. [7] Business Software Alliance, Matt Blaze et al., "Minimum Key Length for Symmetric Ciphers to Provide Adequate Commercial Security", http://www.bsa.org/bsa/cryptologists.html.
[8] RSA Data Security Inc., "RC5 Reference Code in C", See the web site: www.rsa.com, for availability. Not available with the first. draft of this document.
Authors' Addresses
Robert W. Baldwin
RSA Data Security, Inc.
100 Marine Parkway
Redwood City, CA 94065
Phone: (415) 595-8782
Fax: (415) 595-1873
EMail: baldwin@rsa.com, or baldwin@lcs.mit.edu
Ronald L. Rivest
Massachusetts Institute of Technology
Laboratory for Computer Science
NE43-324
545 Technology Square
Cambridge, MA 02139-1986
Phone: (617) 253-5880
EMail: rivest@theory.lcs.mit.eduTop
5 楼moonmistake（）回复于 2002-06-17 09:47:34 得分 50
http://www.chinahacker.net/article/show.php?id=291
呵呵 哥们这个怎么样 ？ 我可找了好多天
文章太长 只好这么写了 要不发到你信箱也可以Top
