Kungani iphakethe le-VPN elibethelwe lingabiza kancane kunalokho okucabangayo

Amaphrofayili amabili alinganiswa esangweni elifanayo, elinye linokubethela elinye lingenakho, futhi elibethelwe alihambi kancane. Ngezinye izikhathi liyashesha, lokho okuvame ukudala impikiswano ende mayelana nokuthi ukuhlolwa kwenziwe ngendlela efanele yini. Umphumela uyazwakala, ngoba izindleko zephakethe akusiyo inani lamagama e-cryptographic ekucushweni. Yiqoqo lemisebenzi eyenziwa ukuqaliswa, kuma-hardware anawo, ngokuhlelwa kwesikhashana asikhethile.

Uphawu: okuhamba kancane akuyona iphrofayili ebethelwe

Ake sithi ukuhlolwa kwakudala kuqhathanisa i-AEAD cipher nemodi „engenakho ukubethela“ esabalala ikhodi yokuqinisekisa ehlukile iphakethe ngalinye. Iphrofayili yesibili ifihla okuqukethwe umthwalo kodwa igcina i-hash iphakethe ngalinye, futhi kusiphathi esingenakho ukusheshiswa kwale hash ingabiza kakhulu kunokwakhiwa okuhlanganisiwe obekufanele ikunqobe.

Ilebula ekucushweni ithi „ukubethela“, futhi ilebula yikho konke ukuqhathanisa okuningi okubhekayo. Indlela yephakethe ithi okunye: iphrofayili eyodwa yenza umsebenzi ohlanganisiwe i-CPU enemiyalelo yawo, kanti enye yenza umsebenzi ohlukile engenayo. Ukufunda ifayela lokucushwa kuphela ngeke kwembule lowo mehluko, ngoba kokubili ukufakwa kubukeka njengomugqa owodwa. Yimodi okuvunyelwene ngayo kanye nendlela yekhodi engemuva kwayo kuphela echaza umphumela.

Yikho konke ukuchaza, futhi akudingi isimangalo sokuthi iyiphi i-primitive eshesha kakhulu emhlabeni wonke. Kokubili kungashesha, kokubili kungahamba kancane, futhi ukulandelana kuncike emshinini nasekhodini.

Bala imisebenzi, hhayi amalebula

Ukwakhiwa kwe-AEAD, njengoba i-RFC 5116 ichaza, kunikeza ukuqaliswa isixhumanisi esisodwa esibuyisela umbhalo obethelwe kanye nethegi ndawonye. I-AES-GCM iyisibonelo esisodwa: ukubethela kwemodi yokubala kuhlangene nomqinisekisi we-Galois. Isixhumanisi asikwenzi ubuqotho bube mahhala; senza inhlanganisela ichazwe kahle, futhi yikho okwenza ukuqaliswa kukwazi ukuthuthukisa umbhangqwana njengeyunithi eyodwa.

Separate authentication path:
  payload -> independent HMAC -> framed packet

AEAD path:
  payload -> authenticated encryption with tag -> framed packet

Lokhu kuyimifanekiso yokucubungula, hhayi izeluleko zokucushwa. Okokuqala akunamfihlo kodwa kusasebenzisa i-CPU ekuqinisekiseni, futhi yingakho „cisha ukubethela“ kungafani nokuthi „cisha umsebenzi we-cryptographic“.

Okwesibili kungashibha ngoba iziphathi zinikeza imiyalelo yazo zombili izingxenye: imijikelezo ye-AES kanye nokuphindaphinda okungenakuthwala okusetshenziswa insimu ye-Galois. Imitapo yezincwadi nayo icubungula amabhafa azimele ngasikhathi sinye, lokho okugcina leyo miyalelo ixakekile esikhundleni sokulinda inkumbulo.

Yini imodi okuvunyelwene ngayo eyenza kube nokwenzeka ngempela

Ku-Community OpenVPN, i-AEAD data cipher isho ukuthi inketho auth ayisachophi i-HMAC yayo ehlukile yesiteshi sedatha. Isithenjwa senketho yokubethela sichaza lobo bubanzi, futhi yisizathu sokuthi ukucushwa okubili okubukeka kufana efayeleni lombhalo kungahluka emsebenzini wephakethe ngalinye.

Funda imodi okuvunyelwene ngayo, hhayi uhlu lwezifiso. Uhlu lwama-cipher avunyelwe kanye negama le-TLS suite akukutsheli ukuthi imiphi imisebenzi egijima kumthwalo, futhi umugqa wakudala we-cipher kungenzeka ungachazi lokho okukhethwe ukuxhumana kwamanje.

openvpn --show-ciphers | head -20
sudo grep -E 'cipher|auth' /etc/openvpn/server.conf

Umyalo wokuqala ubala ama-cipher asekelwa i-binary, okunguhlu lwamakhono hhayi umphumela okuvunyelwene ngawo. Owesibili ukhombisa lokho iseva ekucela ngempela. Ilogi yokuxhumana iyindawo yokuqinisekisa ukukhetha kokugcina, ngoba iklayenti lingawela entweni evunyelwe yiseva kodwa okungekho muntu owayeyihlosile.

Linganisa umthwalo owugijimayo ngempela

Isilinganiso esincane se-cryptographic silinganisa i-primitive ngaphansi kwezimo zayo. Ukudluliswa kwe-VPN nakho kukopisha amabhafa, kuhlela izintambo noma iziphazamiso, kuhlola inqubomgomo futhi kunqamula inethiwekhi. Lezo zingxenye zivame ukubusa, yingakho i-primitive eshesha kakhulu ingahlali ikhiqiza umhubhe oshesha kakhulu.

openssl speed -evp aes-256-gcm
openssl speed -evp sha1

Lemiyalo emibili ikunikeza ukuqhathanisa kwendawo okucashile kwama-primitive emshinini ophambi kwakho, futhi ithembekile ngokuthi yizilinganiso ezincane. Ayisho lutho ngokugeleza komhubhe wakho, futhi akufanele icashunwe kanjalo.

Bese ulinganisa umthwalo obalulekile, ugcina konke okunye kungashintshi: indawo yokugcina efanayo, usayizi wephakethe ofanayo, ukuthutha okufanayo, inqubomgomo yokucindezela efanayo. Uma ushintsho lwephrofayili lushintshe nokuthutha noma indawo yokucubungula, umphumelo uchaza leyo nqwaba hhayi i-cryptography.

Gcina nomgomo emehlweni. Indlela yedatha enamandla ephindiwe e-cryptographic isengaboshwa ukubambezeleka ngoba uhlelo lulinda uhambo lokubuya, futhi izinzuzo zamandla amakhulu azilungisi iphrothokholi ekhuluma kakhulu. Linganisa ukucushwa okusekelwayo nokuvunyelwe inqubomgomo njengokuphelele, futhi ubheke „amabhokisi ambalwa kufanele asheshe“ njengengcamashi eyiyo. Umbuzo owusizo akuwona wokuthi ukubethela kubiza okuthile, kodwa ukuthi lezo zindleko ziyavela esilinganisweni okukhathazeka ngaso ngempela.