A cryptographic hash muaj nuj nqi (CHF) yog ib qho algorithm uas tuaj yeem khiav ntawm cov ntaub ntawv xws li cov ntaub ntawv tus kheej lossis tus password los tsim tus nqi hu ua checksum.
Qhov tseem ceeb ntawm kev siv CHF yog txhawm rau txheeb xyuas qhov tseeb ntawm cov ntaub ntawv. Ob cov ntaub ntawv tuaj yeem xav tias zoo ib yam nkaus xwb yog tias cov checksums tsim los ntawm txhua cov ntaub ntawv, siv tib lub cryptographic hash muaj nuj nqi, zoo ib yam.
Qee qhov feem ntau siv cryptographic hash ua haujlwm suav nrog MD5 thiab SHA-1, txawm tias muaj ntau lwm tus. Cov no feem ntau hu ua "hash functions," tab sis qhov no tsis yog technically raug. Lub hash muaj nuj nqi yog lub ntsiab lus dav dav uas suav nrog CHFs nrog rau lwm yam kev ua haujlwm xws li kev kuaj xyuas kev rov ua dua tshiab.
Cryptographic Hash Function: Ib Qhov Kev Siv
Hais koj rub tawm qhov tseeb version ntawm Firefox browser. Rau qee qhov laj thawj, koj yuav tsum rub tawm nws los ntawm qhov chaw uas tsis yog Mozilla's. Vim tias nws tsis yog nyob rau ntawm qhov chaw koj tau kawm ntseeg, koj xav kom paub tseeb tias cov ntaub ntawv teeb tsa koj nyuam qhuav rub tawm yog tib yam li Mozilla muab.
Siv lub tshuab xam zauv checksum, koj suav cov checksum siv qhov tshwj xeeb cryptographic hash muaj nuj nqi, xws li SHA-2, thiab tom qab ntawd muab piv rau qhov luam tawm ntawm Mozilla lub vev xaib. Yog tias lawv sib npaug, koj tuaj yeem paub tseeb tias qhov rub tawm koj muaj yog qhov Mozilla npaj koj yuav muaj.
Cryptographic Hash Functions tuaj yeem thim rov qab?
Cryptographic hash functions yog tsim los tiv thaiv lub peev xwm rov qab cov checksums lawv tsim rov qab rau cov ntawv qub. Txawm li cas los xij, txawm tias lawv tsis tuaj yeem thim rov qab, lawv tsis yog 100 feem pua tau lav los tiv thaiv cov ntaub ntawv.
Hackers tuaj yeem siv lub rooj zaum zaj sawv los txheeb xyuas cov ntawv dawb ntawm daim tshev. Cov lus Zaj sawv yog cov phau ntawv txhais lus uas sau ntau txhiab, lab, lossis ntau txhiab lab ntawm cov ntawv txheeb xyuas nrog rau lawv cov nqe lus sib xws.
Thaum qhov no tsis yog technically thim rov qab cryptographic hash algorithm, nws yuav zoo li, muab tias nws yooj yim ua. Qhov tseeb tiag, txij li tsis muaj lub rooj zaum zaj sawv tuaj yeem sau txhua qhov kev txheeb xyuas tau nyob rau hauv lub neej, lawv feem ntau tsuas yog pab tau rau cov lus yooj yooj yim xws li tus password tsis muaj zog.
Ntawm no yog qhov yooj yim ntawm cov lus zaj sawv los qhia tias ib tus yuav ua haujlwm li cas thaum siv SHA-1 cryptographic hash muaj nuj nqi:
| Zaj sawv rooj piv txwv | |
|---|---|
| Plaintext | SHA-1 Checksum |
| 12345 | 8cb2237d0679ca88db6464eac60da96345513964 |
| password1 | e38ad214943daad1d64c102faec29de4afe9da3d |
| ilovemydog | a25fb3505406c9ac761c8428692fbf5d5ddf1316 |
| Jenny400 | 7d5eb0173008fe55275d12e9629eef8bdb408c1f |
| dallas1984 | c1ebe6d80f4c7c087ad29d2c0dc3e059fc919da2 |
Ib tug hacker yuav tsum paub qhov twg cryptographic hash algorithm tau siv los tsim cov checksums los txheeb xyuas qhov muaj nuj nqis.
Kev tiv thaiv ntxiv, qee lub vev xaib uas khaws cov neeg siv cov passwords ua haujlwm ntxiv ntawm cryptographic hash algorithm tom qab tus nqi tsim tawm tab sis ua ntej nws khaws cia. Cov txheej txheem no ua rau tus nqi tshiab uas tsuas yog lub vev xaib neeg rau zaub mov nkag siab thiab qhov ntawd tsis sib xws rau thawj daim tshev.
Piv txwv li, tom qab tus password nkag mus thiab cov ntawv txheeb tsim tawm, nws yuav raug muab cais ua ob peb ntu thiab rov kho dua ua ntej nws khaws cia rau hauv password database, lossis qee cov cim yuav raug pauv nrog lwm tus. Thaum sim ua pov thawj rau lub sijhawm tom ntej tus neeg siv kos npe rau, tus neeg rau zaub mov thim rov qab qhov kev ua haujlwm ntxiv no, thiab cov ntawv txheeb xyuas thawj zaug tau tsim dua los xyuas kom meej tias tus neeg siv tus password siv tau.
Ua cov kauj ruam no txwv qhov txiaj ntsig ntawm qhov hack qhov twg tag nrho cov checksums raug nyiag. Lub tswv yim yog los ua ib qho kev ua haujlwm uas tsis paub, yog li yog tias tus neeg nyiag khoom paub qhov cryptographic hash algorithm tab sis tsis yog qhov kev cai, ces paub tus password checksums tsis muaj txiaj ntsig.
Passwords thiab Cryptographic Hash Functions
A database khaws cov neeg siv cov passwords zoo ib yam li cov lus zaj sawv. Thaum koj tus password nkag mus, lub checksum yog tsim thiab muab piv nrog ib qho ntawm cov ntaub ntawv nrog koj lub npe siv. Tom qab ntawd koj tau tso cai nkag mus yog tias ob qho tib si.
Vim tias CHF tsim cov tshev uas tsis thim rov qab, nws puas muaj kev nyab xeeb rau koj los ua koj tus password yooj yim li 12345, tsis yog 12@34 $5, tsuas yog vim cov checksums lawv tus kheej tsis tuaj yeem nkag siab? Tsis yog, thiab ntawm no yog vim li cas.
Ob tus password no ob qho tib si tsis tuaj yeem txiav txim siab tsuas yog saib ntawm daim tshev nyiaj xwb:
MD5 rau 12345: 827ccb0eea8a706c4c34a16891f84e7b
MD5 rau 12@34$5: a4d3cc004f487b18b2ccd4853053818b
Thaum saib, tej zaum koj yuav xav tias nws yog qhov zoo los siv ob tus passwords no. Qhov no muaj tseeb yog tias tus neeg tawm tsam sim txheeb xyuas koj tus password los ntawm kev twv MD5 checksum, uas tsis muaj leej twg ua, tab sis tsis muaj tseeb yog tias muaj kev quab yuam lossis phau ntawv txhais lus raug ua, uas yog ib qho kev sib tw.
A brute force attack tshwm sim thaum muaj ntau yam random stabs raug coj los twv tus password. Hauv qhov no, nws yuav yooj yim twv 12345, tab sis zoo nkauj nyuaj rau randomly xam tawm lwm tus. Kev tawm tsam ntawm phau ntawv txhais lus zoo ib yam li tus neeg tawm tsam tuaj yeem sim txhua lo lus, tus lej, lossis kab lus los ntawm cov npe ntawm cov passwords uas muaj (thiab tsis yog-tseem), thiab 12345 yog ib qho ntawm cov no. passwords.
Txawm hais tias cryptographic hash muaj nuj nqi tsim nyuaj-kom tsis yooj yim-to-xav cov checksums, koj yuav tsum tseem siv tus password nyuaj rau tag nrho koj cov nyiaj hauv online thiab hauv zos.
Xav paub ntau ntxiv ntawm Cryptographic Hash Functions
Nws yuav zoo li kev ua haujlwm cryptographic hash cuam tshuam nrog kev nkag mus, tab sis ob txoj haujlwm sib txawv.
Kev nkag mus yog txheej txheem ob txoj hauv kev uas ib yam dab tsi encrypted los ua tsis tau nyeem thiab tom qab ntawd decrypted tom qab siv ib txwm ua dua. Tej zaum koj yuav encrypt cov ntaub ntawv koj tau khaws cia kom txhua tus neeg uas nkag mus siv tsis tau, lossis koj tuaj yeem siv cov ntaub ntawv hloov chaw encryption los encrypt cov ntaub ntawv uas txav mus rau hauv lub network, xws li cov uas koj upload lossis rub tawm online.
Cryptographic hash functions ua haujlwm sib txawv, nyob rau hauv uas cov checksums tsis txhais tau tias yuav rov qab nrog tus password tshwj xeeb dehashing. Lub hom phiaj nkaus xwb CHFs ua haujlwm yog los sib piv ob daim ntaub ntawv, xws li thaum rub tawm cov ntaub ntawv, khaws cov passwords, thiab rub cov ntaub ntawv los ntawm database.
Nws muaj peev xwm ua tau rau lub cryptographic hash muaj nuj nqi los tsim tib lub checksum rau cov ntaub ntawv sib txawv. Thaum qhov no tshwm sim, nws yog hu ua kev sib tsoo, uas yog qhov teeb meem loj uas xav txog tag nrho cov ntsiab lus ntawm txoj haujlwm yog ua kom cov checksums tshwj xeeb rau txhua cov ntaub ntawv nkag rau hauv nws.
Kev sib tsoo tuaj yeem tshwm sim vim tias txhua CHF tsim tus nqi ntawm qhov ntev tsis hais cov ntaub ntawv nkag. Piv txwv li, MD5 cryptographic hash muaj nuj nqi tsim 827ccb0eea8a706c4c34a16891f84e7b, 1f633b2909b9c1addf32302c7a497983, thiab e10adc3949ba5087b3s ntawm tag nrho cov ntaub ntawv
thawj daim tshev yog los ntawm 12345. Qhov thib ob yog tsim los ntawm ntau tshaj 700 tsab ntawv thiab tus lej, thiab qhov thib peb yog los ntawm 123456. Tag nrho peb qhov kev nkag siab yog qhov ntev sib txawv, tab sis cov txiaj ntsig ib txwm tsuas yog 32 lub cim ntev, txij li MD5 checksum tau siv.
Tsis muaj kev txwv rau tus lej ntawm cov tshev uas tuaj yeem tsim tau vim tias txhua qhov kev hloov pauv me me hauv cov tswv yim yuav tsum tsim cov checksum sib txawv. Vim tias muaj kev txwv rau tus lej ntawm cov checksums uas ib tus CHF tuaj yeem tsim tau, muaj ib txwm muaj peev xwm uas koj yuav ntsib kev sib tsoo.
Qhov no yog vim li cas lwm qhov kev ua haujlwm cryptographic hash tau tsim. Thaum MD5 tsim 32 tus cim tus nqi, SHA-1 tsim 40 tus cim thiab SHA-2 (512) tsim 128. Qhov ntau dua tus lej ntawm cov checksum muaj, qhov tsawg dua qhov kev sib tsoo yuav tshwm sim.
