Cryptographic Hash Function Txhais
Muaj nuj nqi cryptographic hash yog ib hom ntawm algorithm uas tau khiav ntawm cov ntaub ntawv, zoo li cov ntaub ntawv ib tus neeg los yog ib lo lus zais, los tsim cov nqi hu ua checksum.
Lub ntsiab ntawm kev siv cryptographic hash yog los mus xyuas cov authenticity ntawm ib daim ntawm cov ntaub ntawv. Ob cov ntaub ntawv muaj cuab kav ua kom zoo tib yam nkaus xwb yog hais tias tus checksums tau tsim los ntawm txhua cov ntaub ntawv, siv tib lub cryptographic hash muaj nuj nqi, zoo tib yam.
Qee cov kev siv cryptographic hash muaj xws li MD5 thiab SHA-1 , tab sis muaj coob tus kuj muaj nyob.
Lus Cim: Cryptographic hash functions feem ntau yog hu ua hash functions rau luv luv, tab sis qhov tsis yog qhov tseeb. Lub hom hash yog ib lub ntsiab lus ntau ntxiv uas feem ntau siv los encompass cryptographic hash functions nrog lwm hom ntawm algorithms xws li cyclic redundancy tshev.
Cryptographic Hash Functions: Siv Case
Cia hais tias koj download tau qhov tseeb version ntawm Firefox browser . Vim li cas los xij, koj yuav tsum mus download tau nws los ntawm ib qhov chaw uas tsis yog Mozilla's. Tsis yog hosted rau ntawm qhov chaw koj tau kawm ntseeg, koj xav kom paub tseeb tias cov ntaub ntawv installation koj cia li downloaded yog qhov tib yam tshaj plaws Mozilla muaj.
Siv lub checksum calculator , koj txheeb cov checksum siv ib qho kev ua haujlwm cryptographic hash (hais SHA-2) thiab muab piv rau qhov luam tawm ntawm Mozilla qhov chaw.
Yog hais tias lawv muaj vaj huam sib luag, ces koj tuaj yeem paub tseeb tias qhov koj download tau yog ib qhov Mozilla xav kom koj muaj.
Saib Dab Tsi Yog Checksum? rau ntau ntxiv ntawm cov cav laij leb tshwj xeeb, ntxiv rau ntau cov qauv ntawm kev siv checksums kom paub meej tias cov ntaub ntawv koj download tau tiag tiag yog dab tsi koj xav kom lawv ua.
Puas yuav muaj kev Cryptographic Hash Functions Reversed?
Cryptographic hash functions yog tsim los tiv thaiv kom tsis muaj peev xwm los thim cov checksums lawv tsim rov qab rau hauv cov ntawv nyeem.
Txawm li cas los xij, txawm tias lawv tsis muaj peev xwm rov qab los, nws tsis txhais tau tias lawv yog 100% guaranteed los tiv thaiv cov ntaub ntawv.
Tej yam hu ua tus duab zaj dab neeg siv tau kom ceev nrooj tawm lub plaintext ntawm lub checksum. Zaj rooj plaub yog dictionaries yeej sau cov npe tawm txhiab, tsheej lab, los sis txawm billions ntawm no alongside lawv tus nqi ntsuas plaintext.
Thaum qhov no tsis yog kev cuam tshuam cov cryptographic hash algorithm, nws yuav zoo li txij li nws yooj yim heev ua. Nyob hauv kev tseeb, txij thaum tsis muaj zaj dab neeg sau tau tawm txhua tus neeg checksum hauv hav tsuag, lawv feem ntau tsuas yog "pab" rau cov lus yooj yim ... zoo li cov passwords tsis muaj zog.
Ntawm no yog ib qho yooj yim ntawm ib cov duab zaj sawv los ua kom pom li cas ib tug yuav ua hauj lwm thaum siv SHA-1 cryptographic hash muaj nuj nqi:
| Plaintext | SHA-1 Checksum |
| 12345 | 8cb2237d0679ca88db6464eac60da96345513964 |
| password1 | e38ad214943daad1d64c102faec29de4afe9da3d |
| sib tham | a25fb3505406c9ac761c8428692fbf5d5ddf1316 |
| Jenny400 | 7d5eb0173008fe55275d12e9629eef8bdb408c1f |
| dallas1984 | c1ebe6d80f4c7c7c087ad29d2c0dc3e059fc919da2 |
Rau cov kev ntseeg no yuav tsum tau paub txog kev siv cov checksum, xav kom cov hacker to taub uas yog cryptographic hash algorithm tau siv los tsim lawv.
Ntxiv rau kev tiv thaiv, qee cov websites uas muab tus neeg siv cov passwords ua haujlwm ntxiv rau cryptographic hash algorithm tom qab tus nqi yog generated, tiam sis ua ntej nws tau khaws cia.
Qhov no ua rau tus nqi tshiab uas tsuas yog lub web neeg to taub xwb thiab qhov tsis ua raws nraim li daim tseem checksum.
Piv txwv, tom qab tus password nkag los thiab cov checksum generated, nws yuav raug cais mus rau ntau qhov chaw thiab rov qab ua ntej nws tau khaws cia rau hauv tus password database, los yog qee cov cim yuav tau pauv nrog lwm tus. Thaum tus neeg siv sim ua pov thawj lub sij hawm tom qab ntawd lawv kos npe rau, qhov kev ua no ntxiv yuav muab rov qab los ntawm lub web server thiab tus checksum thawj tsim dua, kom paub tseeb tias tus neeg siv tus password siv tau.
Ua qhov no yuav pab txo cov txiaj ntsig ntawm ib qho hack uas tag nrho cov checksums raug nyiag.
Ntxiv dua thiab, lub tswv yim ntawm no yog ua kom muaj nuj nqi uas tsis paub tias yog tias lub hacker paub txog cryptographic hash algorithm tab sis tsis yog qhov kev cai no, ces paub txog lo lus zais checksums yog unhelpful.
Passwords thiab Cryptographic Hash Functions
Zoo li ib cov duab zaj sawv saum toj no yog li cas cov database khaws tseg rau cov neeg siv passwords. Thaum koj tus password nkag mus, tus checksum yog tsim thiab muab piv nrog rau ib daim ntawv teev npe nrog koj tus username. Koj tau raug tso cai nkag yog tias ob leeg zoo tib yam.
Vim tias qhov kev siv cryptographic hash ua ib qho tsis muaj kev cuam tshuam, nws txhais tau tias koj tuaj yeem ua rau koj tus password li yooj yooj yim li 12345 , tsis yog 12 @ 34 $ 5 , vim hais tias cov checksums lawv tus kheej tsis to taub? Nws twv yuav raug hu tsis , thiab ntawm no yog vim li cas ...
Raws li koj tau pom, cov passwords no ob yog ob qho tsis yooj yim sua kom tsis txhob cia saib los ntawm kev sib checksum xwb:
MD5 rau 12345: 827ccb0eea8a706c4c34a16891f84e7b
MD5 rau 12 @ 34 $ 5: a4d3cc004f487b18b2ccd4853053818b
Yog li, thaum xub thawj siab koj yuav xav tias nws zoo nkauj heev rau siv cov passwords no. Qhov no yog qhov tseeb tiag yog tias tus neeg tawm tsam tau sim nrhiav koj tus password los ntawm guessing MD5 checksum (uas tsis muaj leej twg ua), tiam sis tsis muaj tseeb yog tias muaj kev sib ntaus sib tua los yog phau ntawv txhais lus nres (uas yog ib qho kev sib cav sib ceg).
Lub zog quab yuam yog thaum siv ntau hom qhev los ntawm kev khav vaj ib lo lus zais. Hauv qhov no, nws yuav yooj yim rau twv tau "12345," tab sis zoo nkauj tsis yooj yim rau kev xam pom lwm tus. Lub suab npe txhais tau zoo ib yam li tus neeg tawm tsam tau sim txhua lo lus, zauv, los sis kab lus los ntawm cov npe (thiab siv tsawg dua) passwords, "12345" yog qhov tseeb uas yog ib qho uas yuav raug sim.
Yog li, txawm tias cryptographic hash functions ua nyuaj rau checksums tsis yooj yim sua, koj yuav tsum tseem siv ib lo lus zais rau tag nrho koj cov neeg hauv zos thiab hauv zos siv nyiaj.
Ntsis: Saib Cov Poob Hlwb thiab Zog Password yog tias koj tsis paub meej tias koj li yog qhov password tiag.
Xav paub ntxiv txog Cryptographic Hash Functions
Nws yuav zoo li cryptographic hash functions muaj feem xyuam rau encryption tab sis ob txoj hauj lwm hauv kev sib txawv heev.
Encryption yog ob txoj kev uas ib yam dab tsi yog encrypted los ua unreadable, tab sis, ces decrypted tom qab siv dua qub dua. Koj yuav encrypt cov ntaub ntawv koj tau muab kom leej twg nkag mus rau lawv yuav tsis siv lawv, los yog koj siv tau cov ntaub ntawv hloov encryption rau encrypt cov ntaub ntawv uas yog tsiv dua network, xws li ones koj upload lossis download hauv internet.
Zoo li tau piav saum toj no, cryptographic hash functions ua hauj lwm sib txawv hauv cov checksums tsis txhais hais tias yuav tsum tau hloov nrog ib tus password tshwj xeeb de-hashing xws li li cas encrypted cov ntaub ntawv uas tau nyeem nrog tus password tshwj xeeb password. Tsuas yog lub hom phiaj ntawm cryptographic hash functions yog los sib piv ob daim ntawm cov ntaub ntawv, zoo li thaum daus ntaub ntawv, khaws cia cov passwords, rub cov ntaub ntawv los ntawm ib tug database, thiab lwm yam.
Nws yog ua tau rau qhov kev ua hauj lwm cryptographic hash los tsim tib checksum rau ntau daim ntawm cov ntaub ntawv. Thaum qhov no tshwm sim, nws hu ua kev sib tsoo. Kom meej meej, qhov no yog ib qho teeb meem loj heev uas xav txog tag nrho ntawm qhov kev ua hauj lwm hauv kev ua hauj lwm cryptographic yog ua kom tag nrho cov cim checksums rau txhua cov ntaub ntawv muab los rau hauv nws.
Qhov laj thawj sib nraus tuaj yeem yog vim tias txhua qhov kev ua hauj lwm cryptographic hash ua rau muaj nqi ntev npaum li cas los xij. Piv txwv, MD5 cryptographic hash muaj nuj nqi generates 827ccb0eea8a706c4c34a16891f84e7b, 1f633b2909b9c1addf32302c7a497983 , thiab e10adc3949ba59abbe56e057f20f883e rau peb yam sib txawv blocks ntawm cov ntaub ntawv.
Thawj checksum yog los ntawm 12345 , qhov thib ob yog tsim los ntawm ntau tshaj 700 ntawv thiab cov zauv, thiab qhov thib peb yog los ntawm 123456 . Tag nrho peb qhov kev xav yog txawv ntawm cov tiam sis cov ntsiab lus yeej tsuas yog 32 cim ntev txij li siv MD5.
Raws li koj tau pom, muaj zoo tsis pub muaj pes tsawg tus checksums uas yuav raug tsim vim txhua qhov hloov me me hauv cov tswv yim yuav tsum tsim kom muaj kev sib txawv kiag li checksum. Txawm li cas los xij, vim tias muaj kev txwv rau pes tsawg tus checksums ib qhov kev ua hauj lwm cryptographic hash muaj peev xwm tsim tau, muaj yeej ib txwm tau hais tias koj yuav ntsib ib qho kev sib tsoo.
Qhov no yog vim li cas lwm cov kev ua haujlwm cryptographic hash tau raug tsim. Thaum MD5 ua rau muaj nuj nqi 32-cim, SHA-1 generates 40 cim thiab SHA-2 (512) generates 128. Ntau dua cov cim uas checksum tau, qhov tsawg dua qhov kev sib tsoo yuav tshwm sim vim nws muab ntau chav rau cim qhov tseem ceeb.