{"id":477833,"date":"2023-08-09T09:21:11","date_gmt":"2023-08-09T09:21:11","guid":{"rendered":""},"modified":"2023-09-05T11:15:32","modified_gmt":"2023-09-05T11:15:32","slug":"linear-feedback-shift-register","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/linear-feedback-shift-register\/","title":{"rendered":"Thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh"},"content":{"rendered":"<p>C\u00e1c thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh (LFSR) l\u00e0 c\u00e1c thanh ghi d\u1ecbch chuy\u1ec3n tu\u1ea7n t\u1ef1 c\u00f3 c\u01a1 ch\u1ebf ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh. Ch\u00fang \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong c\u00e1c h\u1ec7 th\u1ed1ng k\u1ef9 thu\u1eadt s\u1ed1 \u0111\u1ec3 t\u1ea1o ra c\u00e1c chu\u1ed7i gi\u1ea3 ng\u1eabu nhi\u00ean, ph\u00e1t hi\u1ec7n v\u00e0 s\u1eeda l\u1ed7i c\u0169ng nh\u01b0 c\u00e1c d\u1ea1ng \u0111i\u1ec1u ch\u1ebf k\u1ef9 thu\u1eadt s\u1ed1 kh\u00e1c nhau.<\/p>\n<h2>L\u1ecbch s\u1eed ngu\u1ed3n g\u1ed1c c\u1ee7a thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh v\u00e0 s\u1ef1 \u0111\u1ec1 c\u1eadp \u0111\u1ea7u ti\u00ean v\u1ec1 n\u00f3<\/h2>\n<p>Kh\u00e1i ni\u1ec7m LFSR c\u00f3 t\u1eeb \u0111\u1ea7u nh\u1eefng n\u0103m 1960 khi ch\u00fang l\u1ea7n \u0111\u1ea7u ti\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong radar v\u00e0 vi\u1ec5n th\u00f4ng \u0111\u1ec3 t\u1ea1o ra c\u00e1c chu\u1ed7i gi\u1ea3 ng\u1eabu nhi\u00ean. S\u1ef1 ph\u00e1t tri\u1ec3n ban \u0111\u1ea7u \u0111\u01b0\u1ee3c th\u00fac \u0111\u1ea9y b\u1edfi nhu c\u1ea7u v\u1ec1 nh\u1eefng c\u00e1ch hi\u1ec7u qu\u1ea3 h\u01a1n \u0111\u1ec3 th\u1ef1c hi\u1ec7n ki\u1ec3m tra l\u1ed7i v\u00e0 t\u1ea1o m\u1eabu trong c\u00e1c h\u1ec7 th\u1ed1ng k\u1ef9 thu\u1eadt s\u1ed1. Vi\u1ec7c \u00e1p d\u1ee5ng \u0111\u1ea1i s\u1ed1 tuy\u1ebfn t\u00ednh trong tr\u01b0\u1eddng h\u1eefu h\u1ea1n nh\u1ecb ph\u00e2n \u0111\u00e3 \u0111\u1eb7t n\u1ec1n m\u00f3ng cho n\u1ec1n t\u1ea3ng l\u00fd thuy\u1ebft c\u1ee7a LFSR.<\/p>\n<h2>Th\u00f4ng tin chi ti\u1ebft v\u1ec1 Thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h2>\n<p>LFSR \u0111\u01b0\u1ee3c t\u1ea1o th\u00e0nh t\u1eeb flip-flop v\u00e0 c\u1ed5ng OR (XOR) \u0111\u1ed9c quy\u1ec1n. C\u1ea5u tr\u00fac c\u01a1 b\u1ea3n bao g\u1ed3m vi\u1ec7c d\u1ecbch chuy\u1ec3n n\u1ed9i dung c\u1ee7a thanh ghi v\u00e0 \u0111\u01b0\u1eddng d\u1eabn ph\u1ea3n h\u1ed3i \u0111\u01b0\u1ee3c \u0111i\u1ec1u khi\u1ec3n b\u1edfi m\u1ed9t \u0111a th\u1ee9c \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u0111a th\u1ee9c \u0111\u1eb7c tr\u01b0ng.<\/p>\n<h3>M\u1edf r\u1ed9ng ch\u1ee7 \u0111\u1ec1 v\u1ec1 Thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h3>\n<p>LFSR c\u00f3 nhi\u1ec1u \u1ee9ng d\u1ee5ng:<\/p>\n<ol>\n<li><strong>m\u1eadt m\u00e3<\/strong>: \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng trong m\u1eadt m\u00e3 lu\u1ed3ng \u0111\u1ec3 t\u1ea1o ra c\u00e1c lu\u1ed3ng kh\u00f3a.<\/li>\n<li><strong>X\u1eed l\u00fd t\u00edn hi\u1ec7u s\u1ed1<\/strong>: \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng trong b\u1ed9 m\u00e3 h\u00f3a v\u00e0 b\u1ed9 gi\u1ea3i m\u00e3.<\/li>\n<li><strong>Ph\u00e1t hi\u1ec7n v\u00e0 s\u1eeda l\u1ed7i<\/strong>: \u0110\u01b0\u1ee3c s\u1eed d\u1ee5ng trong thu\u1eadt to\u00e1n ki\u1ec3m tra d\u1ef1 ph\u00f2ng theo chu k\u1ef3 (CRC).<\/li>\n<li><strong>M\u00f4 ph\u1ecfng v\u00e0 th\u1eed nghi\u1ec7m<\/strong>: \u0110\u1ec3 t\u1ea1o c\u00e1c m\u1eabu th\u1eed nghi\u1ec7m trong m\u00f4 ph\u1ecfng ph\u1ea7n c\u1ee9ng.<\/li>\n<\/ol>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a Thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h2>\n<p>M\u1ed9t LFSR bao g\u1ed3m:<\/p>\n<ul>\n<li>M\u1ed9t lo\u1ea1t c\u00e1c flip-flop t\u1ea1o ra m\u1ed9t thanh ghi thay \u0111\u1ed5i.<\/li>\n<li>C\u1ed5ng XOR \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 t\u1ea1o ph\u1ea3n h\u1ed3i.<\/li>\n<li>V\u00f2i, l\u00e0 c\u00e1c \u0111i\u1ec3m c\u1ee5 th\u1ec3 trong thanh ghi d\u1ecbch \u0111\u01b0\u1ee3c k\u1ebft n\u1ed1i v\u1edbi c\u1ed5ng XOR.<\/li>\n<\/ul>\n<h3>C\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng c\u1ee7a Thanh ghi thay \u0111\u1ed5i ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h3>\n<p>D\u1eef li\u1ec7u di chuy\u1ec3n qua flip-flop theo t\u1eebng b\u01b0\u1edbc. Ph\u1ea3n h\u1ed3i \u0111\u01b0\u1ee3c cung c\u1ea5p b\u1edfi c\u00e1c c\u1ed5ng XOR, \u0111\u01b0\u1ee3c \u0111i\u1ec1u khi\u1ec3n b\u1edfi \u0111a th\u1ee9c ph\u1ea3n h\u1ed3i. C\u00e1c thao t\u00e1c nh\u1ea5n quy\u1ebft \u0111\u1ecbnh bit n\u00e0o \u0111\u01b0\u1ee3c \u0111\u01b0a tr\u1edf l\u1ea1i thanh ghi d\u1ecbch, \u1ea3nh h\u01b0\u1edfng \u0111\u1ebfn tr\u00ecnh t\u1ef1 \u0111\u01b0\u1ee3c t\u1ea1o.<\/p>\n<h2>Ph\u00e2n t\u00edch c\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a Thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h2>\n<ul>\n<li><strong>T\u1ea1o gi\u1ea3 ng\u1eabu nhi\u00ean<\/strong>: LFSR c\u00f3 th\u1ec3 t\u1ea1o ra c\u00e1c chu\u1ed7i xu\u1ea5t hi\u1ec7n ng\u1eabu nhi\u00ean nh\u01b0ng c\u00f3 t\u00ednh x\u00e1c \u0111\u1ecbnh.<\/li>\n<li><strong>Hi\u1ec7u qu\u1ea3<\/strong>: \u0110\u1ed9 ph\u1ee9c t\u1ea1p t\u00ednh to\u00e1n th\u1ea5p.<\/li>\n<li><strong>Kh\u1ea3 n\u0103ng d\u1ef1 \u0111o\u00e1n<\/strong>: V\u00ec ch\u00fang c\u00f3 t\u00ednh x\u00e1c \u0111\u1ecbnh n\u00ean tr\u00ecnh t\u1ef1 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c sao ch\u00e9p.<\/li>\n<li><strong>T\u00ednh \u0111\u1ecbnh k\u1ef3<\/strong>: C\u00e1c tr\u00ecnh t\u1ef1 l\u1eb7p l\u1ea1i sau m\u1ed9t \u0111\u1ed9 d\u00e0i nh\u1ea5t \u0111\u1ecbnh \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 kho\u1ea3ng th\u1eddi gian.<\/li>\n<\/ul>\n<h2>C\u00e1c lo\u1ea1i thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h2>\n<p>C\u00f3 hai lo\u1ea1i LFSR ch\u00ednh:<\/p>\n<ol>\n<li>\n<p><strong>Fibonacci LFSR<\/strong>:<\/p>\n<ul>\n<li>S\u1eed d\u1ee5ng ph\u1ea3n h\u1ed3i b\u1ecb tr\u00ec ho\u00e3n.<\/li>\n<li>K\u00e9m hi\u1ec7u qu\u1ea3 h\u01a1n Galois LFSR.<\/li>\n<\/ul>\n<\/li>\n<li>\n<p><strong>LFSR Galois<\/strong>:<\/p>\n<ul>\n<li>S\u1eed d\u1ee5ng ph\u1ea3n h\u1ed3i chia r\u1ebd.<\/li>\n<li>Hi\u1ec7u qu\u1ea3 h\u01a1n v\u1ec1 t\u1ed1c \u0111\u1ed9.<\/li>\n<\/ul>\n<\/li>\n<\/ol>\n<table>\n<thead>\n<tr>\n<th>Ki\u1ec3u<\/th>\n<th>Nh\u1eadn x\u00e9t<\/th>\n<th>Hi\u1ec7u qu\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Fibonacci LFSR<\/td>\n<td>B\u1ecb tr\u00ec ho\u00e3n<\/td>\n<td>Th\u1ea5p h\u01a1n<\/td>\n<\/tr>\n<tr>\n<td>Galois LFSR<\/td>\n<td>\u0110\u00e3 chia ra<\/td>\n<td>Cao h\u01a1n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>C\u00e1c c\u00e1ch s\u1eed d\u1ee5ng Thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh, c\u00e1c v\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p c\u1ee7a ch\u00fang<\/h2>\n<h3>C\u00e1ch s\u1eed d\u1ee5ng<\/h3>\n<ul>\n<li>m\u1eadt m\u00e3<\/li>\n<li>Ki\u1ec3m tra l\u1ed7i<\/li>\n<li>X\u1eed l\u00fd t\u00edn hi\u1ec7u<\/li>\n<\/ul>\n<h3>C\u00e1c v\u1ea5n \u0111\u1ec1<\/h3>\n<ul>\n<li>Kh\u1ea3 n\u0103ng d\u1ef1 \u0111o\u00e1n c\u00f3 th\u1ec3 l\u00e0 m\u1ed9t r\u1ee7i ro b\u1ea3o m\u1eadt.<\/li>\n<li>\u0110a th\u1ee9c ph\u1ea3n h\u1ed3i \u0111\u01b0\u1ee3c ch\u1ecdn kh\u00f4ng ch\u00ednh x\u00e1c c\u00f3 th\u1ec3 d\u1eabn \u0111\u1ebfn hi\u1ec7u su\u1ea5t k\u00e9m.<\/li>\n<\/ul>\n<h3>C\u00e1c gi\u1ea3i ph\u00e1p<\/h3>\n<ul>\n<li>L\u1ef1a ch\u1ecdn c\u1ea9n th\u1eadn \u0111a th\u1ee9c ph\u1ea3n h\u1ed3i.<\/li>\n<li>K\u1ebft h\u1ee3p v\u1edbi c\u00e1c k\u1ef9 thu\u1eadt m\u00e3 h\u00f3a kh\u00e1c \u0111\u1ec3 t\u0103ng c\u01b0\u1eddng b\u1ea3o m\u1eadt.<\/li>\n<\/ul>\n<h2>C\u00e1c \u0111\u1eb7c \u0111i\u1ec3m ch\u00ednh v\u00e0 so s\u00e1nh v\u1edbi c\u00e1c thu\u1eadt ng\u1eef t\u01b0\u01a1ng t\u1ef1<\/h2>\n<table>\n<thead>\n<tr>\n<th>T\u00ednh n\u0103ng<\/th>\n<th>LFSR<\/th>\n<th>Thanh ghi ca kh\u00e1c<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>C\u01a1 ch\u1ebf ph\u1ea3n h\u1ed3i<\/td>\n<td>tuy\u1ebfn t\u00ednh<\/td>\n<td>Phi tuy\u1ebfn t\u00ednh<\/td>\n<\/tr>\n<tr>\n<td>\u0110\u1ed9 ph\u1ee9c t\u1ea1p<\/td>\n<td>Th\u1ea5p<\/td>\n<td>Kh\u00e1c nhau<\/td>\n<\/tr>\n<tr>\n<td>C\u00e1c \u1ee9ng d\u1ee5ng<\/td>\n<td>Nhi\u1ec1u (v\u00ed d\u1ee5: CRC)<\/td>\n<td>C\u1ee5 th\u1ec3<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Quan \u0111i\u1ec3m v\u00e0 c\u00f4ng ngh\u1ec7 c\u1ee7a t\u01b0\u01a1ng lai li\u00ean quan \u0111\u1ebfn thanh ghi d\u1ecbch chuy\u1ec3n ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h2>\n<p>T\u01b0\u01a1ng lai c\u1ee7a LFSR n\u1eb1m \u1edf:<\/p>\n<ul>\n<li>\u0110i\u1ec7n to\u00e1n l\u01b0\u1ee3ng t\u1eed: C\u00e1c \u1ee9ng d\u1ee5ng ti\u1ec1m n\u0103ng trong vi\u1ec7c s\u1eeda l\u1ed7i l\u01b0\u1ee3ng t\u1eed.<\/li>\n<li>M\u1eadt m\u00e3 n\u00e2ng cao: T\u0103ng c\u01b0\u1eddng b\u1ea3o m\u1eadt trong c\u00e1c h\u1ec7 th\u1ed1ng truy\u1ec1n th\u00f4ng hi\u1ec7n \u0111\u1ea1i.<\/li>\n<li>H\u1ec7 th\u1ed1ng t\u00edch h\u1ee3p: Tri\u1ec3n khai ph\u1ea7n c\u1ee9ng hi\u1ec7u qu\u1ea3 h\u01a1n.<\/li>\n<\/ul>\n<h2>C\u00e1ch s\u1eed d\u1ee5ng ho\u1eb7c li\u00ean k\u1ebft m\u00e1y ch\u1ee7 proxy v\u1edbi thanh ghi thay \u0111\u1ed5i ph\u1ea3n h\u1ed3i tuy\u1ebfn t\u00ednh<\/h2>\n<p>C\u00e1c m\u00e1y ch\u1ee7 proxy gi\u1ed1ng nh\u01b0 c\u00e1c m\u00e1y ch\u1ee7 do OneProxy cung c\u1ea5p c\u00f3 th\u1ec3 s\u1eed d\u1ee5ng LFSR \u0111\u1ec3 t\u1ea1o k\u1ebft n\u1ed1i an to\u00e0n v\u00e0 m\u00e3 h\u00f3a d\u1eef li\u1ec7u. Kh\u1ea3 n\u0103ng gi\u1ea3 ng\u1eabu nhi\u00ean c\u1ee7a LFSR c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 t\u0103ng c\u01b0\u1eddng c\u00e1c t\u00ednh n\u0103ng b\u1ea3o m\u1eadt trong m\u00e1y ch\u1ee7 proxy, gi\u00fap kh\u1ea3 n\u0103ng li\u00ean l\u1ea1c tr\u1edf n\u00ean linh ho\u1ea1t h\u01a1n tr\u01b0\u1edbc c\u00e1c cu\u1ed9c t\u1ea5n c\u00f4ng.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<ul>\n<li><a href=\"https:\/\/oneproxy.pro\/vn\/\" target=\"_new\" rel=\"noopener\">Trang web OneProxy<\/a><\/li>\n<li><a href=\"https:\/\/en.wikipedia.org\/wiki\/Linear-feedback_shift_register\" target=\"_new\" rel=\"noopener nofollow\">Wikipedia v\u1ec1 LFSR<\/a><\/li>\n<li><a href=\"https:\/\/www.amazon.com\/Cryptography-Network-Security-Principles-Practice\/dp\/0134444282\" target=\"_new\" rel=\"noopener nofollow\">Gi\u00e1o tr\u00ecnh M\u1eadt m\u00e3 v\u00e0 An ninh m\u1ea1ng<\/a> \u0111\u1ec3 t\u00ecm hi\u1ec3u s\u00e2u h\u01a1n v\u1ec1 vi\u1ec7c s\u1eed d\u1ee5ng LFSR trong m\u1eadt m\u00e3.<\/li>\n<\/ul>","protected":false},"featured_media":477834,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-477833","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Linear-feedback shift register (LFSR)<\/mark>","faq_items":[{"question":"What is a Linear-feedback Shift Register (LFSR)?","answer":"<p>A Linear-feedback Shift Register (LFSR) is a sequential shift register with a linear feedback mechanism, commonly used to generate pseudo-random sequences, detect and correct errors, and in various forms of digital modulation.<\/p>"},{"question":"What are the main applications of LFSRs?","answer":"<p>LFSRs are widely used in cryptography to generate key streams, in digital signal processing for scramblers and descramblers, in error detection and correction algorithms like cyclic redundancy check (CRC), and for generating test patterns in hardware simulation.<\/p>"},{"question":"How does a Linear-feedback Shift Register work?","answer":"<p>An LFSR consists of a series of flip-flops, creating a shift register, XOR gates for feedback, and taps controlling the feedback path. Data moves through the flip-flops, with feedback provided by XOR gates controlled by a feedback polynomial. The sequence generated is influenced by the chosen taps.<\/p>"},{"question":"What are the types of LFSRs?","answer":"<p>There are two main types of LFSRs: Fibonacci LFSRs, which use delayed feedback and are less efficient; and Galois LFSRs, which use divided feedback and are more efficient in terms of speed.<\/p>"},{"question":"What are the key features of LFSRs?","answer":"<p>Key features of LFSRs include pseudo-random generation, low computational complexity, predictability, and periodicity, where sequences repeat after a certain length known as the period.<\/p>"},{"question":"What are the future perspectives of LFSRs?","answer":"<p>The future of LFSRs lies in areas such as quantum computing, advanced cryptography, and more efficient hardware implementations.<\/p>"},{"question":"How can LFSRs be used in association with proxy servers?","answer":"<p>Proxy servers like OneProxy can utilize LFSRs to generate secure connections and encrypt data. The pseudo-random capabilities of LFSRs can enhance security features within the proxy server, making communication more resilient to attacks.<\/p>"},{"question":"What problems might be encountered with LFSRs, and how can they be solved?","answer":"<p>Problems with LFSRs include predictability, which can be a security risk, and poor performance if an incorrect feedback polynomial is chosen. These issues can be mitigated through careful selection of the feedback polynomial and combining LFSRs with other cryptographic techniques.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/477833","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki"}],"about":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/types\/wiki"}],"version-history":[{"count":0,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/477833\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/477834"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=477833"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}