{"id":477433,"date":"2023-08-09T09:14:50","date_gmt":"2023-08-09T09:14:50","guid":{"rendered":""},"modified":"2023-09-05T11:14:42","modified_gmt":"2023-09-05T11:14:42","slug":"hashing","status":"publish","type":"wiki","link":"https:\/\/oneproxy.pro\/vn\/wiki\/hashing\/","title":{"rendered":"B\u0103m"},"content":{"rendered":"<p>B\u0103m l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m c\u01a1 b\u1ea3n trong khoa h\u1ecdc m\u00e1y t\u00ednh, c\u00f3 \u00fd ngh\u0129a r\u1ed9ng trong qu\u1ea3n l\u00fd d\u1eef li\u1ec7u, b\u1ea3o m\u1eadt th\u00f4ng tin v\u00e0 k\u1ebft n\u1ed1i m\u1ea1ng. N\u00f3 \u0111\u1ec1 c\u1eadp \u0111\u1ebfn qu\u00e1 tr\u00ecnh chuy\u1ec3n \u0111\u1ed5i nhi\u1ec1u lo\u1ea1i d\u1eef li\u1ec7u th\u00e0nh m\u1ed9t k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng h\u00e0m b\u0103m, d\u1eabn \u0111\u1ebfn gi\u00e1 tr\u1ecb b\u0103m ho\u1eb7c m\u00e3 b\u0103m duy nh\u1ea5t.<\/p>\n<h2>Ngu\u1ed3n g\u1ed1c v\u00e0 t\u00e0i li\u1ec7u tham kh\u1ea3o ban \u0111\u1ea7u c\u1ee7a b\u0103m<\/h2>\n<p>B\u0103m, nh\u01b0 m\u1ed9t kh\u00e1i ni\u1ec7m khoa h\u1ecdc m\u00e1y t\u00ednh, c\u00f3 ngu\u1ed3n g\u1ed1c t\u1eeb nh\u1eefng n\u0103m 1950. C\u00f4ng tr\u00ecnh \u0111\u1ea7u ti\u00ean v\u1ec1 b\u0103m \u0111\u01b0\u1ee3c Hans Peter Luhn c\u00f4ng b\u1ed1 tr\u00ean t\u1ea1p ch\u00ed IBM v\u00e0o n\u0103m 1953. B\u00e0i b\u00e1o c\u1ee7a \u00f4ng, \u201cM\u1ed9t c\u1ed7 m\u00e1y kinh doanh \u0111\u1ec3 t\u00ecm ki\u1ebfm d\u1eef li\u1ec7u b\u1eb1ng k\u1ef9 thu\u1eadt s\u1ed1\u201d, \u0111\u00e3 gi\u1edbi thi\u1ec7u \u00fd t\u01b0\u1edfng v\u1ec1 m\u00e3 h\u00f3a b\u0103m nh\u01b0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p \u0111\u1ec3 truy xu\u1ea5t th\u00f4ng tin nhanh ch\u00f3ng. Trong nh\u1eefng n\u0103m qua, b\u0103m \u0111\u00e3 tr\u1ea3i qua nh\u1eefng ti\u1ebfn b\u1ed9 \u0111\u00e1ng k\u1ec3, v\u1edbi nhi\u1ec1u h\u00e0m b\u0103m kh\u00e1c nhau \u0111\u01b0\u1ee3c ph\u00e1t tri\u1ec3n v\u00e0 c\u1ea3i ti\u1ebfn \u0111\u1ec3 t\u1ed1i \u01b0u h\u00f3a vi\u1ec7c truy xu\u1ea5t v\u00e0 b\u1ea3o m\u1eadt d\u1eef li\u1ec7u.<\/p>\n<h2>Kh\u00e1m ph\u00e1 h\u00e0m b\u0103m chuy\u00ean s\u00e2u<\/h2>\n<p>V\u1ec1 c\u1ed1t l\u00f5i, b\u0103m l\u00e0 m\u1ed9t ph\u01b0\u01a1ng ph\u00e1p chuy\u1ec3n \u0111\u1ed5i d\u1eef li\u1ec7u\u2014cho d\u00f9 \u0111\u00f3 l\u00e0 v\u0103n b\u1ea3n, t\u1ec7p nh\u1ecb ph\u00e2n hay b\u1ea5t k\u1ef3 lo\u1ea1i th\u00f4ng tin n\u00e0o kh\u00e1c\u2014th\u00e0nh m\u1ed9t chu\u1ed7i byte c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh, t\u01b0\u01a1ng \u0111\u1ed1i ng\u1eafn. Chu\u1ed7i n\u00e0y, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 \u201cb\u0103m\u201d, \u0111\u01b0\u1ee3c b\u1eaft ngu\u1ed3n b\u1eb1ng thu\u1eadt to\u00e1n to\u00e1n h\u1ecdc \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 h\u00e0m b\u0103m.<\/p>\n<p>M\u1ee5c \u0111\u00edch c\u1ee7a h\u00e0m b\u0103m l\u00e0 l\u1ea5y \u0111\u1ea7u v\u00e0o (ho\u1eb7c &#039;th\u00f4ng b\u00e1o&#039;) v\u00e0 tr\u1ea3 v\u1ec1 m\u1ed9t chu\u1ed7i byte c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh. L\u00fd t\u01b0\u1edfng nh\u1ea5t l\u00e0 \u0111\u1ea7u ra ph\u1ea3i cung c\u1ea5p s\u1ef1 ph\u00e2n ph\u1ed1i m\u1ed9t chi\u1ec1u, x\u00e1c \u0111\u1ecbnh v\u00e0 th\u1ed1ng nh\u1ea5t. Ngh\u0129a l\u00e0, c\u00f9ng m\u1ed9t \u0111\u1ea7u v\u00e0o s\u1ebd lu\u00f4n t\u1ea1o ra c\u00f9ng m\u1ed9t h\u00e0m b\u0103m, nh\u01b0ng vi\u1ec7c thay \u0111\u1ed5i ngay c\u1ea3 m\u1ed9t ph\u1ea7n nh\u1ecf c\u1ee7a \u0111\u1ea7u v\u00e0o c\u0169ng s\u1ebd t\u1ea1o ra m\u1ed9t h\u00e0m b\u0103m ho\u00e0n to\u00e0n kh\u00e1c.<\/p>\n<p>B\u0103m ch\u1ee7 y\u1ebfu \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c c\u1ea5u tr\u00fac d\u1eef li\u1ec7u nh\u01b0 b\u1ea3ng b\u0103m v\u00e0 c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 truy xu\u1ea5t d\u1eef li\u1ec7u nhanh ch\u00f3ng, c\u0169ng nh\u01b0 trong c\u00e1c ch\u1ee9c n\u0103ng m\u00e3 h\u00f3a \u0111\u1ec3 duy tr\u00ec t\u00ednh to\u00e0n v\u1eb9n v\u00e0 b\u1ea3o m\u1eadt d\u1eef li\u1ec7u.<\/p>\n<h2>C\u1ea5u tr\u00fac b\u00ean trong c\u1ee7a b\u0103m: C\u00e1ch th\u1ee9c ho\u1ea1t \u0111\u1ed9ng<\/h2>\n<p>C\u01a1 ch\u1ebf b\u0103m bao g\u1ed3m m\u1ed9t s\u1ed1 b\u01b0\u1edbc, t\u00f9y thu\u1ed9c v\u00e0o \u0111\u1ed9 ph\u1ee9c t\u1ea1p c\u1ee7a h\u00e0m b\u0103m:<\/p>\n<ol>\n<li>\n<p><strong>D\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o<\/strong>: Qu\u00e1 tr\u00ecnh b\u0103m b\u1eaft \u0111\u1ea7u v\u1edbi m\u1ed9t s\u1ed1 d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o. \u0110\u00e2y c\u00f3 th\u1ec3 l\u00e0 b\u1ea5t c\u1ee9 th\u1ee9 g\u00ec t\u1eeb m\u1ed9t chu\u1ed7i v\u0103n b\u1ea3n \u0111\u1ebfn t\u1ec7p nh\u1ecb ph\u00e2n.<\/p>\n<\/li>\n<li>\n<p><strong>H\u00e0m b\u0103m<\/strong>: D\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o \u0111\u01b0\u1ee3c truy\u1ec1n qua h\u00e0m b\u0103m. T\u00f9y thu\u1ed9c v\u00e0o thu\u1eadt to\u00e1n c\u1ee5 th\u1ec3, h\u00e0m n\u00e0y c\u00f3 th\u1ec3 th\u1ef1c hi\u1ec7n nhi\u1ec1u thao t\u00e1c kh\u00e1c nhau\u2014nh\u01b0 c\u00e1c ph\u00e9p to\u00e1n d\u1ecbch chuy\u1ec3n, g\u1ea5p ho\u1eb7c modulo\u2014\u0111\u1ec3 chuy\u1ec3n \u0111\u1ed5i d\u1eef li\u1ec7u.<\/p>\n<\/li>\n<li>\n<p><strong>Gi\u00e1 tr\u1ecb b\u0103m<\/strong>: H\u00e0m b\u0103m xu\u1ea5t ra m\u1ed9t chu\u1ed7i k\u00fd t\u1ef1 c\u00f3 k\u00edch th\u01b0\u1edbc c\u1ed1 \u0111\u1ecbnh, b\u1ea5t k\u1ec3 k\u00edch th\u01b0\u1edbc c\u1ee7a d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o. \u0110\u00e2y l\u00e0 gi\u00e1 tr\u1ecb b\u0103m ho\u1eb7c m\u00e3 b\u0103m.<\/p>\n<\/li>\n<li>\n<p><strong>X\u1eed l\u00fd va ch\u1ea1m<\/strong>: N\u1ebfu hai \u0111\u1ea7u v\u00e0o kh\u00e1c nhau t\u1ea1o ra c\u00f9ng m\u1ed9t h\u00e0m b\u0103m (&quot;xung \u0111\u1ed9t&quot;), th\u00ec h\u00e0m b\u0103m ph\u1ea3i c\u00f3 c\u00e1ch x\u1eed l\u00fd n\u00f3, th\u01b0\u1eddng b\u1eb1ng c\u00e1ch thay \u0111\u1ed5i h\u00e0m b\u0103m m\u1ed9t ch\u00fat b\u1eb1ng quy tr\u00ecnh g\u1ecdi l\u00e0 &quot;b\u0103m l\u1ea1i&quot;.<\/p>\n<\/li>\n<\/ol>\n<p>\u0110\u1eb7c \u0111i\u1ec3m \u0111\u1ed9c \u0111\u00e1o c\u1ee7a h\u00e0m b\u0103m l\u00e0 n\u00f3 c\u00f3 t\u00ednh x\u00e1c \u0111\u1ecbnh\u2014c\u00f3 ngh\u0129a l\u00e0 c\u00f9ng m\u1ed9t \u0111\u1ea7u v\u00e0o s\u1ebd lu\u00f4n t\u1ea1o ra c\u00f9ng m\u1ed9t gi\u00e1 tr\u1ecb b\u0103m.<\/p>\n<h2>C\u00e1c t\u00ednh n\u0103ng ch\u00ednh c\u1ee7a b\u0103m<\/h2>\n<p>B\u0103m \u0111i k\u00e8m v\u1edbi m\u1ed9t s\u1ed1 t\u00ednh n\u0103ng \u0111\u00e1ng ch\u00fa \u00fd:<\/p>\n<ul>\n<li>\n<p><strong>T\u1ed1c \u0111\u1ed9<\/strong>: Vi\u1ec7c b\u0103m cho ph\u00e9p \u0111\u1ed9 ph\u1ee9c t\u1ea1p v\u1ec1 th\u1eddi gian kh\u00f4ng \u0111\u1ed5i (O(1)) \u0111\u1ec3 truy xu\u1ea5t d\u1eef li\u1ec7u, ngh\u0129a l\u00e0 t\u1ed1c \u0111\u1ed9 truy xu\u1ea5t c\u1ef1c k\u1ef3 nhanh, b\u1ea5t k\u1ec3 k\u00edch th\u01b0\u1edbc c\u1ee7a t\u1eadp d\u1eef li\u1ec7u.<\/p>\n<\/li>\n<li>\n<p><strong>Ch\u1ee7 ngh\u0129a quy\u1ebft \u0111\u1ecbnh<\/strong>: C\u00f9ng m\u1ed9t \u0111\u1ea7u v\u00e0o s\u1ebd lu\u00f4n t\u1ea1o ra c\u00f9ng m\u1ed9t gi\u00e1 tr\u1ecb b\u0103m.<\/p>\n<\/li>\n<li>\n<p><strong>T\u00ednh \u0111\u1ed3ng nh\u1ea5t<\/strong>: H\u00e0m b\u0103m t\u1ed1t t\u1ea1o ra s\u1ef1 ph\u00e2n b\u1ed1 \u0111\u1ed3ng \u0111\u1ec1u c\u00e1c gi\u00e1 tr\u1ecb b\u0103m, gi\u1ea3m thi\u1ec3u kh\u1ea3 n\u0103ng x\u1ea3y ra xung \u0111\u1ed9t.<\/p>\n<\/li>\n<li>\n<p><strong>Ch\u1ee9c n\u0103ng m\u1ed9t chi\u1ec1u<\/strong>: V\u1ec1 m\u1eb7t t\u00ednh to\u00e1n, vi\u1ec7c thi\u1ebft k\u1ebf ng\u01b0\u1ee3c d\u1eef li\u1ec7u \u0111\u1ea7u v\u00e0o ban \u0111\u1ea7u t\u1eeb gi\u00e1 tr\u1ecb b\u0103m l\u00e0 kh\u00f4ng kh\u1ea3 thi. \u0110\u1eb7c \u0111i\u1ec3m n\u00e0y \u0111\u1eb7c bi\u1ec7t quan tr\u1ecdng trong vi\u1ec7c b\u0103m m\u1eadt m\u00e3.<\/p>\n<\/li>\n<\/ul>\n<h2>C\u00e1c lo\u1ea1i b\u0103m<\/h2>\n<p>B\u0103m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c ph\u00e2n lo\u1ea1i theo nhi\u1ec1u c\u00e1ch kh\u00e1c nhau. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 m\u1ed9t s\u1ed1 lo\u1ea1i b\u0103m:<\/p>\n<table>\n<thead>\n<tr>\n<th>Ki\u1ec3u<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>H\u00e0m b\u0103m m\u1eadt m\u00e3<\/strong><\/td>\n<td>Ch\u00fang \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 b\u1ea3o m\u1eadt v\u00e0 \u0111\u00e1p \u1ee9ng c\u00e1c y\u00eau c\u1ea7u c\u1ee5 th\u1ec3, ch\u1eb3ng h\u1ea1n nh\u01b0 kh\u00f4ng th\u1ec3 t\u1ea1o l\u1ea1i \u0111\u1ea7u v\u00e0o ban \u0111\u1ea7u t\u1eeb h\u00e0m b\u0103m. V\u00ed d\u1ee5 bao g\u1ed3m SHA-256 v\u00e0 MD5.<\/td>\n<\/tr>\n<tr>\n<td><strong>H\u00e0m b\u0103m phi m\u1eadt m\u00e3<\/strong><\/td>\n<td>Ch\u00fang \u0111\u01b0\u1ee3c t\u1ed1i \u01b0u h\u00f3a cho hi\u1ec7u su\u1ea5t trong c\u00e1c t\u00e1c v\u1ee5 nh\u01b0 truy xu\u1ea5t d\u1eef li\u1ec7u. H\u1ecd kh\u00f4ng \u01b0u ti\u00ean b\u1ea3o m\u1eadt. C\u00e1c v\u00ed d\u1ee5 bao g\u1ed3m h\u00e0m b\u0103m Murmur v\u00e0 Fowler\u2013Noll\u2013Vo (FNV).<\/td>\n<\/tr>\n<tr>\n<td><strong>B\u0103m th\u1ed1ng nh\u1ea5t<\/strong><\/td>\n<td>M\u1ed9t lo\u1ea1i h\u00e0m b\u0103m trong \u0111\u00f3 m\u1ecdi h\u00e0m b\u0103m \u0111\u1ec1u c\u00f3 kh\u1ea3 n\u0103ng nh\u01b0 nhau, gi\u1ea3m thi\u1ec3u kh\u1ea3 n\u0103ng x\u1ea3y ra xung \u0111\u1ed9t.<\/td>\n<\/tr>\n<tr>\n<td><strong>B\u0103m ho\u00e0n h\u1ea3o<\/strong><\/td>\n<td>Ph\u01b0\u01a1ng ph\u00e1p b\u0103m hai c\u1ea5p trong \u0111\u00f3 kh\u00f4ng c\u00f3 xung \u0111\u1ed9t \u1edf c\u1ea5p \u0111\u1ed9 th\u1ee9 hai. \u0110i\u1ec1u n\u00e0y l\u00fd t\u01b0\u1edfng cho c\u00e1c t\u1eadp d\u1eef li\u1ec7u t\u0129nh.<\/td>\n<\/tr>\n<tr>\n<td><strong>B\u0103m nh\u1ea5t qu\u00e1n<\/strong><\/td>\n<td>Ki\u1ec3u b\u0103m n\u00e0y \u0111\u1eb7c bi\u1ec7t h\u1eefu \u00edch trong c\u00e1c h\u1ec7 th\u1ed1ng ph\u00e2n t\u00e1n v\u00ec n\u00f3 gi\u1ea3m thi\u1ec3u vi\u1ec7c b\u0103m l\u1ea1i khi b\u1ea3ng b\u0103m \u0111\u01b0\u1ee3c thay \u0111\u1ed5i k\u00edch th\u01b0\u1edbc.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>\u1ee8ng d\u1ee5ng, v\u1ea5n \u0111\u1ec1 v\u00e0 gi\u1ea3i ph\u00e1p li\u00ean quan \u0111\u1ebfn b\u0103m<\/h2>\n<p>B\u0103m c\u00f3 nhi\u1ec1u \u1ee9ng d\u1ee5ng:<\/p>\n<ol>\n<li>\n<p><strong>Ph\u1ee5c h\u1ed3i d\u1eef li\u1ec7u<\/strong>: B\u0103m \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng r\u1ed9ng r\u00e3i trong c\u00e1c c\u1ea5u tr\u00fac d\u1eef li\u1ec7u nh\u01b0 b\u1ea3ng b\u0103m v\u00e0 c\u01a1 s\u1edf d\u1eef li\u1ec7u \u0111\u1ec3 cho ph\u00e9p truy xu\u1ea5t d\u1eef li\u1ec7u nhanh ch\u00f3ng.<\/p>\n<\/li>\n<li>\n<p><strong>m\u1eadt m\u00e3<\/strong>: H\u00e0m b\u0103m m\u1eadt m\u00e3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong nhi\u1ec1u \u1ee9ng d\u1ee5ng b\u1ea3o m\u1eadt kh\u00e1c nhau, nh\u01b0 x\u00e1c minh t\u00ednh to\u00e0n v\u1eb9n c\u1ee7a d\u1eef li\u1ec7u v\u00e0 l\u01b0u tr\u1eef m\u1eadt kh\u1ea9u m\u1ed9t c\u00e1ch an to\u00e0n.<\/p>\n<\/li>\n<li>\n<p><strong>Ch\u1ee9c n\u0103ng b\u1ed9 \u0111\u1ec7m<\/strong>: B\u0103m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c thu\u1eadt to\u00e1n b\u1ed9 nh\u1edb \u0111\u1ec7m \u0111\u1ec3 t\u00ecm n\u1ea1p d\u1eef li\u1ec7u nhanh h\u01a1n.<\/p>\n<\/li>\n<\/ol>\n<p>Tuy nhi\u00ean, c\u00f3 nh\u1eefng th\u00e1ch th\u1ee9c li\u00ean quan \u0111\u1ebfn b\u0103m:<\/p>\n<ul>\n<li>\n<p><strong>Va ch\u1ea1m<\/strong>: \u0110i\u1ec1u n\u00e0y x\u1ea3y ra khi hai \u0111\u1ea7u v\u00e0o kh\u00e1c nhau t\u1ea1o ra c\u00f9ng m\u1ed9t h\u00e0m b\u0103m. N\u00f3 c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c gi\u1ea3m thi\u1ec3u b\u1eb1ng c\u00e1ch s\u1eed d\u1ee5ng h\u00e0m b\u0103m t\u1ed1t gi\u00fap gi\u1ea3m kh\u1ea3 n\u0103ng x\u1ea3y ra xung \u0111\u1ed9t v\u00e0 c\u01a1 ch\u1ebf x\u1eed l\u00fd xung \u0111\u1ed9t t\u1ed1t, nh\u01b0 x\u00e2u chu\u1ed7i ho\u1eb7c \u0111\u1ecba ch\u1ec9 m\u1edf.<\/p>\n<\/li>\n<li>\n<p><strong>B\u1ea3o v\u1ec7<\/strong>: M\u1eb7c d\u00f9 c\u00e1c h\u00e0m b\u0103m m\u1eadt m\u00e3 \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 b\u1ea3o m\u1eadt, nh\u01b0ng c\u00e1c h\u00e0m b\u0103m phi m\u1eadt m\u00e3 kh\u00f4ng v\u00e0 kh\u00f4ng n\u00ean \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng cho d\u1eef li\u1ec7u b\u1ea3o m\u1eadt.<\/p>\n<\/li>\n<\/ul>\n<h2>B\u0103m so v\u1edbi c\u00e1c kh\u00e1i ni\u1ec7m t\u01b0\u01a1ng t\u1ef1<\/h2>\n<p>M\u1eb7c d\u00f9 b\u0103m l\u00e0 m\u1ed9t kh\u00e1i ni\u1ec7m \u0111\u1ed9c \u0111\u00e1o nh\u01b0ng n\u00f3 c\u00f3 nh\u1eefng \u0111i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng v\u1edbi c\u00e1c k\u1ef9 thu\u1eadt m\u00e3 h\u00f3a v\u00e0 qu\u1ea3n l\u00fd d\u1eef li\u1ec7u kh\u00e1c. D\u01b0\u1edbi \u0111\u00e2y l\u00e0 so s\u00e1nh b\u0103m v\u1edbi m\u1ed9t v\u00e0i kh\u00e1i ni\u1ec7m t\u01b0\u01a1ng t\u1ef1:<\/p>\n<table>\n<thead>\n<tr>\n<th>\u00dd t\u01b0\u1edfng<\/th>\n<th>S\u1ef1 mi\u00eau t\u1ea3<\/th>\n<th>\u0110i\u1ec3m t\u01b0\u01a1ng \u0111\u1ed3ng<\/th>\n<th>S\u1ef1 kh\u00e1c bi\u1ec7t<\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>M\u00e3 h\u00f3a<\/strong><\/td>\n<td>M\u1ed9t ph\u01b0\u01a1ng ph\u00e1p ng\u1ee5y trang d\u1eef li\u1ec7u \u0111\u1ec3 b\u1ea3o v\u1ec7 t\u00ednh b\u00ed m\u1eadt c\u1ee7a n\u00f3.<\/td>\n<td>C\u1ea3 hai \u0111\u1ec1u li\u00ean quan \u0111\u1ebfn vi\u1ec7c chuy\u1ec3n \u0111\u1ed5i d\u1eef li\u1ec7u t\u1eeb d\u1ea1ng n\u00e0y sang d\u1ea1ng kh\u00e1c.<\/td>\n<td>M\u00e3 h\u00f3a \u0111\u01b0\u1ee3c thi\u1ebft k\u1ebf \u0111\u1ec3 c\u00f3 th\u1ec3 \u0111\u1ea3o ng\u01b0\u1ee3c (v\u1edbi kh\u00f3a b\u00ean ph\u1ea3i), trong khi b\u0103m l\u00e0 m\u1ed9t chi\u1ec1u v\u00e0 kh\u00f4ng th\u1ec3 \u0111\u1ea3o ng\u01b0\u1ee3c.<\/td>\n<\/tr>\n<tr>\n<td><strong>M\u00e3 h\u00f3a<\/strong><\/td>\n<td>Qu\u00e1 tr\u00ecnh chuy\u1ec3n \u0111\u1ed5i d\u1eef li\u1ec7u t\u1eeb d\u1ea1ng n\u00e0y sang d\u1ea1ng kh\u00e1c.<\/td>\n<td>C\u1ea3 hai \u0111\u1ec1u li\u00ean quan \u0111\u1ebfn vi\u1ec7c chuy\u1ec3n \u0111\u1ed5i d\u1eef li\u1ec7u.<\/td>\n<td>M\u00e3 h\u00f3a nh\u1eb1m m\u1ee5c \u0111\u00edch \u0111\u1ea1i di\u1ec7n ch\u1ee9 kh\u00f4ng ph\u1ea3i \u0111\u1ec3 b\u1ea3o m\u1eadt. N\u00f3 c\u00f3 th\u1ec3 \u0111\u1ea3o ng\u01b0\u1ee3c, trong khi b\u0103m th\u00ec kh\u00f4ng.<\/td>\n<\/tr>\n<tr>\n<td><strong>T\u1ed5ng ki\u1ec3m tra<\/strong><\/td>\n<td>Ki\u1ec3m tra t\u00ednh to\u00e0n v\u1eb9n d\u1eef li\u1ec7u \u0111\u01a1n gi\u1ea3n \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o d\u1eef li\u1ec7u kh\u00f4ng b\u1ecb h\u1ecfng trong qu\u00e1 tr\u00ecnh truy\u1ec1n.<\/td>\n<td>C\u1ea3 hai \u0111\u1ec1u t\u1ea1o ra m\u1ed9t chu\u1ed7i ng\u1eafn t\u1eeb d\u1eef li\u1ec7u l\u1edbn h\u01a1n.<\/td>\n<td>T\u1ed5ng ki\u1ec3m tra kh\u00f4ng ph\u1ea3i l\u00e0 duy nh\u1ea5t ho\u1eb7c an to\u00e0n v\u00e0 m\u1ee5c \u0111\u00edch duy nh\u1ea5t c\u1ee7a ch\u00fang l\u00e0 ki\u1ec3m tra l\u1ed7i ch\u1ee9 kh\u00f4ng ph\u1ea3i \u0111\u1ec3 b\u1ea3o v\u1ec7 d\u1eef li\u1ec7u.<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<h2>Quan \u0111i\u1ec3m t\u01b0\u01a1ng lai v\u00e0 c\u00f4ng ngh\u1ec7 li\u00ean quan \u0111\u1ebfn b\u0103m<\/h2>\n<p>Trong t\u01b0\u01a1ng lai, b\u0103m s\u1ebd ti\u1ebfp t\u1ee5c \u0111\u00f3ng vai tr\u00f2 quan tr\u1ecdng trong khoa h\u1ecdc m\u00e1y t\u00ednh v\u00e0 qu\u1ea3n l\u00fd d\u1eef li\u1ec7u. S\u1ef1 ra \u0111\u1eddi c\u1ee7a \u0111i\u1ec7n to\u00e1n l\u01b0\u1ee3ng t\u1eed \u0111\u1eb7t ra th\u00e1ch th\u1ee9c \u0111\u1ed1i v\u1edbi vi\u1ec7c b\u0103m, \u0111\u1eb7c bi\u1ec7t l\u00e0 b\u0103m m\u1eadt m\u00e3, v\u00ec thu\u1eadt to\u00e1n l\u01b0\u1ee3ng t\u1eed c\u00f3 th\u1ec3 ph\u00e1 v\u1ee1 c\u00e1c h\u00e0m b\u0103m hi\u1ec7n t\u1ea1i. \u0110i\u1ec1u n\u00e0y \u0111\u00e3 d\u1eabn \u0111\u1ebfn s\u1ef1 ph\u00e1t tri\u1ec3n c\u1ee7a c\u00e1c h\u00e0m b\u0103m kh\u00e1ng l\u01b0\u1ee3ng t\u1eed.<\/p>\n<p>Ngo\u00e0i ra, v\u1edbi s\u1ef1 t\u0103ng tr\u01b0\u1edfng nhanh ch\u00f3ng c\u1ee7a d\u1eef li\u1ec7u, c\u00e1c h\u00e0m b\u0103m th\u1eadm ch\u00ed c\u00f2n nhanh h\u01a1n v\u00e0 gi\u1ea3m thi\u1ec3u xung \u0111\u1ed9t s\u1ebd ng\u00e0y c\u00e0ng tr\u1edf n\u00ean quan tr\u1ecdng trong c\u01a1 s\u1edf d\u1eef li\u1ec7u v\u00e0 c\u00e1c \u1ee9ng d\u1ee5ng d\u1eef li\u1ec7u quy m\u00f4 l\u1edbn kh\u00e1c.<\/p>\n<h2>M\u00e1y ch\u1ee7 b\u0103m v\u00e0 proxy<\/h2>\n<p>B\u0103m c\u00f3 nh\u1eefng \u1ee9ng d\u1ee5ng th\u1ef1c t\u1ebf trong ho\u1ea1t \u0111\u1ed9ng c\u1ee7a m\u00e1y ch\u1ee7 proxy. V\u00ed d\u1ee5: b\u0103m c\u00f3 th\u1ec3 \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng \u0111\u1ec3 ph\u00e2n ph\u1ed1i t\u1ea3i \u0111\u1ed3ng \u0111\u1ec1u tr\u00ean nhi\u1ec1u m\u00e1y ch\u1ee7 trong m\u1ea1ng proxy. K\u1ef9 thu\u1eadt n\u00e0y, \u0111\u01b0\u1ee3c g\u1ecdi l\u00e0 b\u0103m nh\u1ea5t qu\u00e1n, gi\u00fap tr\u00e1nh ph\u1ea3i b\u0103m l\u1ea1i m\u1ecdi th\u1ee9 khi m\u00e1y ch\u1ee7 \u0111\u01b0\u1ee3c th\u00eam ho\u1eb7c x\u00f3a.<\/p>\n<p>H\u01a1n n\u1eefa, b\u0103m c\u00f3 th\u1ec3 t\u0103ng c\u01b0\u1eddng t\u00ednh b\u1ea3o m\u1eadt c\u1ee7a m\u00e1y ch\u1ee7 proxy. V\u00ed d\u1ee5: x\u00e1c th\u1ef1c m\u1eadt kh\u1ea9u b\u0103m th\u01b0\u1eddng \u0111\u01b0\u1ee3c s\u1eed d\u1ee5ng trong c\u00e1c m\u00e1y ch\u1ee7 proxy \u0111\u1ec3 \u0111\u1ea3m b\u1ea3o t\u00ednh b\u1ea3o m\u1eadt c\u1ee7a m\u1eadt kh\u1ea9u.<\/p>\n<h2>Li\u00ean k\u1ebft li\u00ean quan<\/h2>\n<p>\u0110\u1ec3 bi\u1ebft th\u00eam th\u00f4ng tin v\u1ec1 b\u0103m, b\u1ea1n c\u00f3 th\u1ec3 tham kh\u1ea3o c\u00e1c t\u00e0i nguy\u00ean sau:<\/p>\n<ol>\n<li>\n<p><a href=\"https:\/\/towardsdatascience.com\/what-is-hashing-6edba0ebfa67\" target=\"_new\" rel=\"noopener nofollow\">\u201cB\u0103m l\u00e0 g\u00ec?\u201d \u2013 H\u01b0\u1edbng t\u1edbi khoa h\u1ecdc d\u1eef li\u1ec7u<\/a><\/p>\n<\/li>\n<li>\n<p><a href=\"https:\/\/medium.com\/tech-tales\/what-is-hashing-6edba0ebfa67\" target=\"_new\" rel=\"noopener nofollow\">\u201cH\u00e0m b\u0103m v\u00e0 c\u00e1ch s\u1eed d\u1ee5ng ch\u00fang trong khoa h\u1ecdc m\u00e1y t\u00ednh\u201d \u2013 Medium<\/a><\/p>\n<\/li>\n<li>\n<p><a href=\"https:\/\/www.freecodecamp.org\/news\/a-beginners-guide-to-hashing-in-computer-science-471c80a7c8b5\/\" target=\"_new\" rel=\"noopener nofollow\">\u201cH\u01b0\u1edbng d\u1eabn b\u0103m trong khoa h\u1ecdc m\u00e1y t\u00ednh cho ng\u01b0\u1eddi m\u1edbi b\u1eaft \u0111\u1ea7u\u201d \u2013 freeCodeCamp<\/a><\/p>\n<\/li>\n<li>\n<p><a href=\"https:\/\/www.geeksforgeeks.org\/overview-of-hashing-and-its-computer-science-applications\/\" target=\"_new\" rel=\"noopener nofollow\">\u201cT\u1ed5ng quan v\u1ec1 B\u0103m v\u00e0 c\u00e1c \u1ee9ng d\u1ee5ng khoa h\u1ecdc m\u00e1y t\u00ednh c\u1ee7a n\u00f3\u201d - GeeksforGeeks<\/a><\/p>\n<\/li>\n<li>\n<p><a href=\"https:\/\/en.wikipedia.org\/wiki\/Hash_function\" target=\"_new\" rel=\"noopener nofollow\">\u201cH\u00e0m b\u0103m\u201d \u2013 Wikipedia<\/a><\/p>\n<\/li>\n<\/ol>\n<p>H\u00e3y nh\u1edb r\u1eb1ng, v\u1edbi t\u01b0 c\u00e1ch l\u00e0 nh\u00e0 cung c\u1ea5p m\u00e1y ch\u1ee7 proxy \u0111\u00e1ng tin c\u1eady c\u1ee7a b\u1ea1n, OneProxy hi\u1ec3u t\u1ea7m quan tr\u1ecdng c\u1ee7a c\u00e1c giao th\u1ee9c b\u1ea3o m\u1eadt m\u1ea1nh m\u1ebd v\u00e0 c\u01a1 ch\u1ebf truy xu\u1ea5t d\u1eef li\u1ec7u t\u1ed1i \u01b0u. V\u1edbi c\u00f4ng ngh\u1ec7 ti\u00ean ti\u1ebfn v\u00e0 cam k\u1ebft v\u1ec1 b\u1ea3o m\u1eadt, ch\u00fang t\u00f4i c\u1ed1 g\u1eafng cung c\u1ea5p d\u1ecbch v\u1ee5 t\u1ed1t nh\u1ea5t c\u00f3 th\u1ec3 cho kh\u00e1ch h\u00e0ng.<\/p>","protected":false},"featured_media":477434,"menu_order":0,"template":"","meta":{"_acf_changed":false,"content-type":"","inline_featured_image":false,"footnotes":""},"class_list":["post-477433","wiki","type-wiki","status-publish","has-post-thumbnail","hentry"],"acf":{"faq_title":"Frequently Asked Questions about <mark>Hashing: A Comprehensive Overview<\/mark>","faq_items":[{"question":"What is hashing in computer science?","answer":"<p>Hashing is a process in computer science where a hash function transforms an input of data into a fixed-size string of bytes, typically a hash value or hash code. This unique output represents the input data, serving various purposes from swift data retrieval to maintaining data security.<\/p>"},{"question":"Who introduced the concept of hashing?","answer":"<p>The concept of hashing was first introduced by Hans Peter Luhn, an IBM scientist, in a paper published in 1953. The paper, titled \"A Business Machine for Data Searching by Digital Techniques,\" presented hash coding as a method for rapid information retrieval.<\/p>"},{"question":"How does a hash function work?","answer":"<p>A hash function works by taking an input (or 'message') and returning a fixed-size string of bytes. The output is designed to be deterministic and uniformly distributed, meaning the same input will always generate the same output, and changing a tiny part of the input will yield a significantly different output. A good hash function also has mechanisms to handle collisions, where different inputs produce the same hash.<\/p>"},{"question":"What are some key features of hashing?","answer":"<p>Some key features of hashing include its speed, allowing for swift data retrieval regardless of the dataset's size, determinism where the same input always yields the same hash value, and one-way functionality which makes it computationally challenging to reverse-engineer the original input from the hash value.<\/p>"},{"question":"What are the different types of hashing?","answer":"<p>There are various types of hashing including cryptographic hash functions (like SHA-256 and MD5) designed for secure data integrity, non-cryptographic hash functions (like Murmur and Fowler\u2013Noll\u2013Vo (FNV)) optimized for performance, uniform hashing for evenly distributed hash values, perfect hashing ideal for static sets of data, and consistent hashing beneficial in distributed systems.<\/p>"},{"question":"What are some applications and problems related to hashing?","answer":"<p>Hashing is commonly used in data retrieval for hash tables and databases, cryptography for data integrity and secure password storage, and caching for swift data fetch. However, it's not without problems, with collision (two different inputs producing the same hash) being a key issue, as well as security concerns in non-cryptographic hash functions.<\/p>"},{"question":"How does hashing relate to proxy servers?","answer":"<p>Hashing can be applied in the operation of proxy servers in ways such as using consistent hashing to distribute loads evenly across servers in a proxy network, and enhancing security with hashed password authentication.<\/p>"},{"question":"What does the future hold for hashing technologies?","answer":"<p>Future technologies will continue to leverage hashing, with quantum-resistant hash functions and hash functions optimized for large-scale data applications being key areas of focus. This is largely due to the advent of quantum computing and the rapid growth of data respectively.<\/p>"}]},"_links":{"self":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/wiki\/477433","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\/477433\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media\/477434"}],"wp:attachment":[{"href":"https:\/\/oneproxy.pro\/vn\/wp-json\/wp\/v2\/media?parent=477433"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}