- == 系统问题，暂停聊天功能。==
- 【征集】西西河的经济学，及清流措施，需要主动参与者，『稷下学宫』新认证方式，24年网站打算和努力目标
主题：【原创by 1001n】也说说密码 -- 不爱吱声
家园 【原创by 1001n】也说说密码 也说说密码
终于有人开始谈论密码学了。。密码这东西太有意思了，确实是人类纯智力对抗的最顶峰表现。相比被媒体吹到天上的国际象棋大赛什么的，密码的对抗才的的确确表现了群体的支持下，智力会发展成什么样子……
从似乎是亚历山大时代，用皮带缠绕木棍刻下文字，然后将皮带做为密信发给远方开始，密码的对抗就在不断升级。之后的简单加密，比如单字替代法，错位法，开始似乎都是很有前途的。但是，一个简单的频率分析法，让无论怎么替代的字母都得现出原形――谁让发明拼音化语言总有这个缺陷呢
与之同期出现的指代法和暗语法，相对安全一点。比如指代法，就象镖局主人兄所说的，用书籍和诗句中的内容掩饰。但是，一般的书籍发行不是一本，诗句也未必只有几个人知道。越多的人可能拥有加密的参考资源，密码也就越不可靠。
比较而言，暗语法应用更为广泛一些。比如二战时期日军用AF指代中途岛，已经是鼎鼎大名的例子了。只是，AF是被美军用特殊值法（嘿嘿）猜出来了，还有更多的没被猜出来，或者没被公布的。而没猜出来的，也就躲过去了，达到了密码设置的目的.
当密码发展到非单字替换的时代以后，大规模的密码对抗才真正开始成型。二战中伦敦的布列奇里公园成为了一个密码学上的里程碑，因为它有两重意义：第一，它集合了全国的天才，以集体智慧的形式真正开始了密码学意义上的国家对抗；第二，他们所对付的ENIGMA这种机器密码（每发送一个字母，密钥盘都会转动，无规律可循，――我记得不牢，它好像是三层密钥盘还是五层密钥盘层层变换加密来着，每天都用不同的电路排线结构确定当前唯一的转动加密顺序――除非你造出同样一台机器，或者得到每天变换的密码本），也是人类智力的杰作。而最后的结果是，ENIGMA被打败了，U艇一艘艘地沉没在冰冷的大西洋和太平洋的海底……
吴宇森的风语战士，说的也是密码。一个只懂罕见语言的战士，被重点保护，以避免泄密――因为密码就是用他的语言写就的。个人看法，这应该只是军内的低级密码。而高级密码，不会那么简单，ENIGMA已经是个明显的例子了。
麦家以前写过几部小说，解密，和后来的几部，记不清名字了，从文学角度上，还是很好看的，有兴趣的兄弟不妨找来看看。
至于现在的密码，特别是我国的密码学进展，就实在很难窥到门径了。象前一阵子热闹的MD5被发现存在碰撞，就是一个很少见的浮出水面的例子。尽管MD5加密并不因此失去全部价值，碰撞也是有条件的――但是如果任何一种稍微高级的密码以此原理写就，它的命运就只有一个了：被毫不留情地废弃。
再以前，新浪军事的海军论坛曾经巨牛无比的帖子《海军上校访谈录》里曾经以我军某海军上校的口气提到，咱们的密码，要是不懂易经八卦，趁早别碰……之类，呵呵，至于有没有那么神，那就不得而知了。可以总结的是，建国以前，我们的军用高级密码，是没有被对手破译的。建国以后就很难说了，我个人倾向于大概没有吧。但是近来经常说我国泄密严重，似乎总以文件丢失、机密被拍照之类的形式，具体到全面失密，也就是密码被破译，似乎还没听说过。话说回来，文件丢失之类的事件，或许又是敌方的幌子，为的是掩护真正的已经破译密码了。。也说不定。德军ENIGMA在二战中被破译了，英国不是冒着本土被轰炸的危险也绝对不动用破译出来的德军通信来抗击么？只是希望了，希望咱们的密码永远不要被破译，咱们的数学家、计算机专家、物理学家……多多用力，一定能够确保我们的安全吧。
最后，提一本书，名字叫《军事密码学》（好像是），大概是解放军出版社出的。。惭愧，记得不太清楚了。在我印象中，国内很少出这种书籍的。不过，书里也没有泄密，嘿嘿，主要是详细地讲了讲密码学的原理，比如，频率分析的公式，错位或替代加密的公式破解法，以及科普性质的密码学讲述。看起来，还是很有意思的，也很锻炼脑子，推荐给国内有兴趣的兄弟们读读。
最后提一句，忘了是不是麦家说的，“密码是人类发明的一个恶魔”……这话，仔细体会一下，真是很有道理啊。
元宝推荐：不爱吱声,家园 看过小说《解密》作者麦家，讲的也是这方面的事情，很精彩 - -- 系统屏蔽 --。
家园 破译者--戴维卡恩：解放军文艺出版社 The Codebreakers, a book on history of cryptography by David Kahn
http://david-kahn.com/david-kahn-biography.htm
David Kahn:
Expert in codes; cryptography; political military and communications intelligence; author of books, articles and publications on ciphers and American intelligence
David Kahn is a historian of intelligence, particularly of communications intelligence, or codebreaking. In addition to his books, Kahn has written scholarly and popular articles on the subject of codes, cryptography and ciphers in publications ranging from The New York Times to Playboy, from the Journal of Strategic Studies to the Encyclopedia Americana. Some of David Kahn's articles about codes, codebreaking, and cryptography are featured in the Articles section of this site. David Kahn lectures widely on political and military intelligence and appears on television and radio and in news stories to give the historical background of current events in the area of ciphers, codes, and cryptography. Kahn has taught courses on modern political and military intelligence at Yale and Columbia and has testified before Congress on policy matters dealing with cryptography. Though David Kahn makes his home in Great Neck, Long Island, a suburb of New York, he has lived for a year or more in Washington, Paris, Freiburg-im-Breisgau (location of the Militärarchiv), and Oxford, places in which he met many political and military intelligence professionals.
Dr. Kahn’s lifelong love affair with codes and cryptography began when, as a boy in Great Neck, he read Fletcher Pratt’s Secret and Urgent, a 1939 history of codes, ciphers, and cryptography. He joined the American Cryptogram Association and, later, the New York Cipher Society. After college (Bucknell University) and while working as a reporter for Newsday, the Long Island daily, David Kahn wrote an article for The New York Times Magazine in 1960 backgrounding the revelations of two defectors from the National Security Agency, the nation’s supersecret code-making and -breaking organization. This led to a contract to write a book on codes and cryptography, some of which was written during his two years as an editor on the International Herald Tribune in Paris. The Codebreakers was published in September 1967; it was a Book of the Month Club alternate selection and a History Book Club main selection. The Pulitzer jury selected the book for the 1968 general nonfiction prize, but the Pulitzer board awarded the prize instead to Will and Ariel Durant. The Codebreakers has remained in print continuously, with translations of the book published in whole or in part in French, Italian, Polish, Serbo-Croatian, and Arabic; a second edition appeared in 1995; a thorough revision of the book into a paperback is contemplated.
David Kahn then decided to investigate German military intelligence in World War II, which lay at the intersection of thorough Teutonic scholarship and legendary German arms. For this he went to the Militärarchiv, learned German, and for a year researched and interviewed more than 100 intelligence specialists in Germany. After writing in New York for a couple of years, David Kahn became a senior associate member of St. Antony’s College of Oxford University, where he used his research to write his dissertation; he was awarded the D. Phil. (the Oxonian designation) in 1974. Hitler’s Spies was published in 1978.
After teaching journalism for a few years at New York University, Kahn returned to Newsday as an op-ed editor. While there, he researched and wrote Seizing the Enigma (1991), the story of how the Royal Navy captured documents from German weather ships to enable British codebreakers to read Kriegsmarine Enigma intercepts and help win the Battle of the Atlantic. In 1995, he was selected as the scholar in residence at the National Security Agency. He refused security clearances. The agency asked him to write a biography of the founder of American cryptography, Herbert O. Yardley. Though it declassified its documents about Yardley, these technical and administrative papers did not suffice for a biography, so David Kahn visited Yardley’s home town in Indiana and Los Angeles, where he wrote movie scripts, to find the documents that would tell the human story of America's first code-breaker. The result is The Reader of Gentlemen’s Mail – a title adapted from the famous quote by Secretary of State Henry L. Stimson about his reason for closing down Yardley’s codebreaking agency in 1929: “Gentlemen do not read each other’s mail.”
David Kahn retired from Newsday in 1998. He continues to write articles on political and military intelligence (see bibliography and Articles section). Kahn sits on the boards of trustees of the Great Neck Library, the World War II Studies Association, the National Cryptologic Museum Foundation, and the International Intelligence History Association and on the board of advisors of the International Spy Museum. He is a founding co-editor of the scholarly quarterly Cryptologia and is a member of the boards of editors of Intelligence and National Security, the International Journal of Intelligence and CounterIntelligence and The Journal of Intelligence History. Kahn is a member of the American Cryptogram Association, the International Association for Cryptologic Research (former board member and former member of the editorial board of its Journal of Cryptology) and the American Historical Association. David Kahn recently donated much of his collection of books, offprints, interview notes, and journals dealing with codes, cryptography, and intelligence to the National Cryptologic Museum Foundation at Fort Meade, Maryland.
At present Dr. Kahn is writing a one-volume study of American intelligence in World War II for Viking Penguin. He plans other projects after that.
David Kahn lives in Great Neck. He is amicably divorced from the former Susanne Fiedler and has two sons, Oliver and Michael. A few more details, mostly unnecessary, may be found in Who’s Who in America.
Copyright © 2000-2002 David Kahn. All rights reserved.
家园 密码跟明码有什么区别呐？ 为甚么SOS就是明码呐？
（好象这个问题有点弱智呢。。。。。）西西。
我小时候的理想之一就是当个间谍。。因为当时住的大院，有个小楼里有发电报的，还老不让我们小孩进去。那时候一直认为那发电报的漂亮阿姨就是个间谍。。。。
家园 阅不懂 不过使劲支持，不懂的肯定是高级的
