{"id":7955,"date":"2023-08-25T00:00:00","date_gmt":"2023-08-25T00:00:00","guid":{"rendered":"https:\/\/tech-lib.eu\/tech\/jak-funguje-md5\/"},"modified":"2023-08-25T00:00:00","modified_gmt":"2023-08-25T00:00:00","slug":"jak-funguje-md5","status":"publish","type":"post","link":"https:\/\/tech-lib.eu\/tech\/jak-funguje-md5\/","title":{"rendered":"Jak funguje MD5"},"content":{"rendered":"
\n
How to generate MD5 hash for a file?<\/div>\n
Type the following command: md5sum [type file name with extension here] [path of the file] — NOTE: You can also drag the file to the terminal window instead of typing the full path. Hit the Enter key. You'll see the MD5 sum of the file.<\/div>\n
\n\t\t\t\t\t Dal\u0161\u00ed informace najdete na<\/span> www.autodesk.com<\/a>\n\t\t\t\t<\/div>\n<\/p><\/div>\n
\n
<\/div>\n

B\u011b\u017en\u00fd kryptografick\u00fd hashovac\u00ed algoritmus, kter\u00fd se pou\u017e\u00edv\u00e1 ke kontrole spr\u00e1vnosti dat a k ov\u011b\u0159en\u00ed, \u017ee s nimi nebylo manipulov\u00e1no, se naz\u00fdv\u00e1 MD5 (Message Digest Algorithm 5). Ronald Rivest jej vytvo\u0159il v roce 1991 a od t\u00e9 doby se stal jedn\u00edm z nejpou\u017e\u00edvan\u011bj\u0161\u00edch hashovac\u00edch algoritm\u016f na sv\u011bt\u011b. Tento \u010dl\u00e1nek se bude zab\u00fdvat algoritmem MD5, v\u010detn\u011b toho, jak funguje, k jak\u00fdm \u00fa\u010del\u016fm slou\u017e\u00ed, jak jej lze prolomit a zda jej lze odemknout. <\/p>\n

<\/div>\n

Jak se MD5 pou\u017e\u00edv\u00e1? Co je MD5? <\/p>\n

<\/div>\n

Jako jednosm\u011brn\u00e1 hashovac\u00ed funkce generuje MD5 ze vstupu (nebo zpr\u00e1vy) libovoln\u00e9 d\u00e9lky v\u00fdstup o pevn\u00e9 velikosti, obvykle 128bitovou (16bajtovou) hashovac\u00ed hodnotu. Proto\u017ee vstupn\u00ed data ur\u010duj\u00ed tuto hodnotu hash sama o sob\u011b, i mal\u00e9 zm\u011bny povedou ke zcela odli\u0161n\u00e9 hodnot\u011b hash. Pomoc\u00ed algoritmu MD5 se \u010dasto kontroluje integrita soubor\u016f, hesel a digit\u00e1ln\u00edch podpis\u016f. <\/p>\n

<\/div>\n

Z hlediska pou\u017eit\u00ed se algoritmus MD5 \u010dasto pou\u017e\u00edv\u00e1 p\u0159i kontrole integrity dat a v po\u010d\u00edta\u010dov\u00e9 kriminalistice. Aby bylo jist\u00e9, \u017ee soubor nebyl b\u011bhem p\u0159enosu zm\u011bn\u011bn, je obvyklou prax\u00ed porovn\u00e1vat hodnotu hash souboru p\u0159ed p\u0159enosem a po n\u011bm. Podobn\u00fdm zp\u016fsobem se pou\u017e\u00edv\u00e1 k bezpe\u010dn\u00e9mu ukl\u00e1d\u00e1n\u00ed hesel jejich hashov\u00e1n\u00edm a porovn\u00e1v\u00e1n\u00edm hodnot hash v pr\u016fb\u011bhu procesu ov\u011b\u0159ov\u00e1n\u00ed, ani\u017e by se samotn\u00e1 hesla skute\u010dn\u011b ukl\u00e1dala. <\/p>\n

<\/div>\n

Jak je hash MD5 poru\u0161en? A\u010dkoli byl MD5 d\u0159\u00edve pova\u017eov\u00e1n za bezpe\u010dn\u00fd, zlep\u0161en\u00ed v\u00fdpo\u010detn\u00edho v\u00fdkonu zp\u016fsobilo, \u017ee je n\u00e1chyln\u00fd k \u0159ad\u011b \u00fatok\u016f. Obl\u00edbenou technikou de\u0161ifrov\u00e1n\u00ed hashe MD5 je pou\u017eit\u00ed duhov\u00fdch tabulek. P\u0159edem vypo\u010dten\u00e1 tabulka obsahuj\u00edc\u00ed hodnoty hash pro v\u0161echny potenci\u00e1ln\u00ed vstupy a\u017e do ur\u010dit\u00e9 d\u00e9lky je zn\u00e1m\u00e1 jako duhov\u00e1 tabulka. P\u016fvodn\u00ed vstup lze identifikovat porovn\u00e1n\u00edm hodnoty hashe zn\u00e1m\u00e9ho hashe MD5 se z\u00e1znamy v duhov\u00e9 tabulce. <\/p>\n

<\/div>\n

Dal\u0161\u00edm zp\u016fsobem prolomen\u00ed hashe MD5 jsou \u00fatoky hrubou silou. Pro nalezen\u00ed spr\u00e1vn\u00e9ho vstupu, kter\u00fd generuje pot\u0159ebn\u00fd v\u00fdsledek hash, je t\u0159eba vyzkou\u0161et v\u0161echny kombinace znak\u016f. Tento p\u0159\u00edstup v\u0161ak m\u016f\u017ee b\u00fdt pom\u011brn\u011b n\u00e1ro\u010dn\u00fd na \u010das a prost\u0159edky, zejm\u00e9na v p\u0159\u00edpad\u011b del\u0161\u00edch vstup\u016f nebo slo\u017eit\u00fdch hesel. <\/p>\n

<\/div>\n

Lze MD5 de\u0161ifrovat? <\/p>\n

<\/div>\n

MD5 nelze de\u0161ifrovat, tedy ne. Z\u00e1kladn\u00ed my\u0161lenkou hashovac\u00ed funkce je, \u017ee se jedn\u00e1 o jednosm\u011brnou funkci, co\u017e znamen\u00e1, \u017ee je vytvo\u0159ena tak, aby bylo jednoduch\u00e9 vypo\u010d\u00edtat hodnotu hash ze vstupu, ale v\u00fdpo\u010detn\u011b nemo\u017en\u00e9 prov\u00e9st opak. V\u00fdsledkem je, \u017ee zat\u00edmco de\u0161ifrov\u00e1n\u00ed je mo\u017en\u00e9 pomoc\u00ed d\u0159\u00edve uveden\u00fdch metod, prolomen\u00ed hashe MD5 nen\u00ed provediteln\u00e9. <\/p>\n

<\/div>\n

Hashov\u00e1n\u00ed nebo \u0161ifrov\u00e1n\u00ed MD5? Je t\u0159eba objasnit skute\u010dnost, \u017ee MD5 je metoda hashov\u00e1n\u00ed, a nikoli \u0161ifrovac\u00ed algoritmus. Hashov\u00e1n\u00ed zahrnuje p\u0159evod dat na hashovac\u00ed hodnotu pevn\u00e9 velikosti, kterou nelze zvr\u00e1tit, zat\u00edmco \u0161ifrov\u00e1n\u00ed vy\u017eaduje p\u0159evod dat do podoby, kterou lze zvr\u00e1tit pomoc\u00ed de\u0161ifrovac\u00edho kl\u00ed\u010de. Proto\u017ee MD5 nepou\u017e\u00edv\u00e1 kl\u00ed\u010d ani transformaci, kterou by bylo mo\u017en\u00e9 zru\u0161it, jedn\u00e1 se o hashovac\u00ed funkci. <\/p>\n

<\/div>\n

Shrneme-li to, MD5 je obl\u00edben\u00fd kryptografick\u00fd hashovac\u00ed algoritmus, kter\u00fd pro jak\u00fdkoli vstup vytv\u00e1\u0159\u00ed odli\u0161nou hashovac\u00ed hodnotu. Pou\u017e\u00edv\u00e1 se pro digit\u00e1ln\u00ed podpisy, ukl\u00e1d\u00e1n\u00ed hesel a kontrolu integrity dat. A\u010dkoli byl d\u0159\u00edve algoritmus MD5 pova\u017eov\u00e1n za bezpe\u010dn\u00fd, zlep\u0161en\u00ed v\u00fdpo\u010detn\u00edho v\u00fdkonu jej u\u010dinilo n\u00e1chyln\u011bj\u0161\u00edm k \u00fatok\u016fm. Pomoc\u00ed technik, jako jsou duhov\u00e9 tabulky a \u00fatoky hrubou silou, lze hash MD5 prolomit, ale dek\u00f3dov\u00e1n\u00ed nen\u00ed mo\u017en\u00e9. Je d\u016fle\u017eit\u00e9 si uv\u011bdomit, \u017ee MD5 je hashovac\u00ed metoda, nikoli \u0161ifrovac\u00ed algoritmus, proto\u017ee nepou\u017e\u00edv\u00e1 \u0161ifrovac\u00ed kl\u00ed\u010de ani reverzibiln\u00ed transformace.<\/p><\/div>\n

\n
FAQ<\/div>\n
\n
Jak pou\u017e\u00edvat MD5 v datab\u00e1zi?<\/div>\n

V datab\u00e1zi byste pro pou\u017eit\u00ed MD5 obvykle provedli n\u00e1sleduj\u00edc\u00ed kroky: 1. Vyberte informace, kter\u00e9 chcete v datab\u00e1zi ulo\u017eit jako hash MD5. M\u016f\u017ee to b\u00fdt u\u017eivatelsk\u00e9 jm\u00e9no, heslo nebo jak\u00e1koli jin\u00e1 soukrom\u00e1 informace, kterou chcete udr\u017eet v tajnosti. 2. P\u0159ed vlo\u017een\u00edm dat do datab\u00e1ze je zaheslujte pomoc\u00ed techniky MD5. B\u011b\u017enou kryptografickou hashovac\u00ed funkc\u00ed je MD5, kter\u00e1 p\u0159ij\u00edm\u00e1 vstup a vypisuje pevnou velikost, jedine\u010dn\u00fd v\u00fdsledek hashov\u00e1n\u00ed. 3. Pomoc\u00ed programovac\u00edho jazyka nebo datab\u00e1zov\u00e9 funkce, kter\u00e1 podporuje ha\u0161ov\u00e1n\u00ed MD5, transformujte p\u016fvodn\u00ed data na odpov\u00eddaj\u00edc\u00ed ha\u0161ovac\u00ed hodnotu MD5. K vytvo\u0159en\u00ed hodnoty hash lze pou\u017e\u00edt nap\u0159\u00edklad funkci MD5 v jazyce SQL. 4. Do datab\u00e1ze ulo\u017ete hashovac\u00ed hodnotu MD5 nam\u00edsto p\u016fvodn\u00edch dat. T\u00edm, \u017ee je pro neopr\u00e1vn\u011bn\u00e9 osoby obt\u00ed\u017en\u011bj\u0161\u00ed de\u0161ifrovat p\u016fvodn\u00ed data z hashe, pom\u00e1h\u00e1 to chr\u00e1nit citliv\u00e1 data. 5. Zopakovali byste postup ha\u0161ov\u00e1n\u00ed MD5 na vstupu a porovnali jej s hodnotou ha\u0161e MD5 ulo\u017eenou v datab\u00e1zi pro ov\u011b\u0159en\u00ed nebo porovn\u00e1n\u00ed dat, nap\u0159\u00edklad hesla. Pokud se ob\u011b hodnoty hash shoduj\u00ed, je vstup platn\u00fd. <\/p>\n

<\/div>\n

Proto\u017ee je MD5 zraniteln\u00fd v\u016f\u010di probl\u00e9m\u016fm, jako jsou kolize a p\u0159edobrazov\u00e9 \u00fatoky, je z bezpe\u010dnostn\u00edch d\u016fvod\u016f pova\u017eov\u00e1n za pom\u011brn\u011b slab\u00fd hashovac\u00ed algoritmus. Proto se pro zv\u00fd\u0161en\u00ed bezpe\u010dnosti v sou\u010dasn\u00fdch aplikac\u00edch doporu\u010duje pou\u017e\u00edvat siln\u011bj\u0161\u00ed hashovac\u00ed metody, jako je SHA-256. <\/p>\n<\/div>\n

\n
Je MD5 st\u00e1le u\u017eite\u010dn\u00fd?<\/div>\n

Ano, MD5 je v n\u011bkter\u00fdch situac\u00edch st\u00e1le u\u017eite\u010dn\u00fd, ale jeho pou\u017e\u00edv\u00e1n\u00ed pro aplikace vy\u017eaduj\u00edc\u00ed zabezpe\u010den\u00ed se doporu\u010duje st\u00e1le m\u00e9n\u011b. Message Digest Algorithm 5 neboli MD5 generuje 128bitov\u00fd (16bajtov\u00fd) v\u00fdsledek hashov\u00e1n\u00ed a je obl\u00edbenou kryptografickou hashovac\u00ed funkc\u00ed. <\/p>\n

<\/div>\n

MD5 je v\u0161ak zraniteln\u00fd v\u016f\u010di kolizn\u00edm \u00fatok\u016fm, kdy dva r\u016fzn\u00e9 vstupy mohou kv\u016fli zn\u00e1m\u00fdm chyb\u00e1m v\u00e9st ke stejn\u00e9 hodnot\u011b hash. Kv\u016fli t\u00e9to chyb\u011b nelze MD5 pou\u017e\u00edvat pro kritick\u00e9 aplikace integrity dat, jako je ukl\u00e1d\u00e1n\u00ed hesel nebo digit\u00e1ln\u00ed podpisy. <\/p>\n

<\/div>\n

Navzdory sv\u00fdm nedostatk\u016fm m\u00e1 MD5 st\u00e1le n\u011bkolik u\u017eite\u010dn\u00fdch aplikac\u00ed. Lze jej pou\u017e\u00edt pro nekryptografick\u00e9 c\u00edle, jako je rychl\u00e1 identifikace identick\u00fdch soubor\u016f nebo kontroln\u00ed sou\u010dty soubor\u016f pro zaji\u0161t\u011bn\u00ed integrity dat. V n\u011bkter\u00fdch nekritick\u00fdch aplikac\u00edch nebo star\u0161\u00edch syst\u00e9mech se MD5 tak\u00e9 p\u0159\u00edle\u017eitostn\u011b pou\u017e\u00edv\u00e1. <\/p>\n

<\/div>\n

V bezpe\u010dnostn\u011b citliv\u00fdch sc\u00e9n\u00e1\u0159\u00edch se doporu\u010duje pou\u017e\u00edvat bezpe\u010dn\u011bj\u0161\u00ed hashovac\u00ed funkce, nap\u0159\u00edklad SHA-256 nebo bcrypt, kter\u00e9 jsou pova\u017eov\u00e1ny za odoln\u011bj\u0161\u00ed v\u016f\u010di kolizn\u00edm \u00fatok\u016fm.<\/p>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

How to generate MD5 hash for a file? Type the following command: md5sum [type file name with extension here] [path of the file] — NOTE: You can also drag the file to the terminal window instead of typing the full path. Hit the Enter key. You'll see the MD5 sum of the file. Dal\u0161\u00ed informace … \u010c\u00edst d\u00e1l<\/a><\/p>\n","protected":false},"author":705,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3104],"tags":[],"class_list":["post-7955","post","type-post","status-publish","format-standard","hentry","category-kryptografie"],"_links":{"self":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/posts\/7955","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/users\/705"}],"replies":[{"embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/comments?post=7955"}],"version-history":[{"count":0,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/posts\/7955\/revisions"}],"wp:attachment":[{"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/media?parent=7955"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/categories?post=7955"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/tech-lib.eu\/tech\/wp-json\/wp\/v2\/tags?post=7955"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}