Stream Cipher vs Block Cipher | State Cipher vs Block Cipher
Nyob rau hauv cryptography, Stream ciphers thiab Block ciphers yog ob lub encryption/decryption algorithms uas yog tsev neeg ntawm symmetric key ciphers. Feem ntau tus cipher yuav siv cov ntawv sau yooj yim raws li kev nkag thiab tsim cov ntawv cipher raws li cov zis. Thaiv ciphers encrypts taag-ntev thaiv ntawm cov khoom siv kev hloov pauv tsis sib xws. kwj ciphers encrypt cov kwj ntawm cov khoom nrog qhov ntev sib txawv thiab siv qhov sib txawv ntawm txhua qhov me me.
Dab tsi yog Stream Cipher?
Stream ciphers yog tsev neeg ntawm symmetric key ciphers. kwj ciphers ua ke cov ntawv nyeem me me nrog cov pseudorandom cipher cov khoom ntws nrog kev siv XOR (tsuas yog-lossis).kwj ciphers encrypt cov lej-ntawv nyeem ib zaug nrog sib txawv hloov pauv rau cov lej txuas ntxiv. Vim hais tias qhov encryption ntawm txhua tus lej nyob ntawm lub xeev tam sim no ntawm lub tshuab cipher, kwj ciphers tseem hu ua lub xeev ciphers. Feem ntau, ib qho me me / tom yog siv los ua ib tus lej. Txhawm rau kom tsis txhob muaj kev txhawj xeeb txog kev nyab xeeb, nws yuav tsum tau ua kom paub tseeb tias tib lub xeev pib tsis siv ntau dua ib zaug. Feem ntau siv kwj cipher yog RC4.
Dab tsi yog Block Cipher?
Ib thaiv cipher yog lwm qhov tseem ceeb cipher. Thaiv ciphers ua haujlwm ntawm cov blocks (pab pawg ntawm cov khoom) nrog ntev-ntev. Thaiv ciphers siv qhov hloov pauv tsis tu ncua (tsis hloov pauv) rau txhua tus lej hauv qhov thaiv. Piv txwv li, thaum ib qho x-ntsis thaiv cov ntawv nyeem (nrog rau tus yuam sij zais cia) yog muab tso rau hauv lub cav cipher, nws tsim cov x-ntsis thaiv ntawm ciphertext. Qhov kev hloov pauv tiag tiag yog nyob ntawm tus yuam sij zais cia. Ib yam li ntawd, lub decryption algorithm rov qab tau qhov qub x-ntsis thaiv ntawm plaintext siv x-ntsis thaiv ntawm ciphertext thiab tus yuam sij zais cia saum toj no raws li cov tswv yim. Nyob rau hauv rooj plaub uas cov lus tawm tswv yim ntev dhau los piv rau qhov loj ntawm qhov thaiv, nws yuav tawg mus rau cov blocks thiab cov blocks no yuav yog (ib leeg) encrypted siv tib tus yuam sij. Txawm li cas los xij, vim tias tib tus yuam sij raug siv, txhua qhov rov ua ntu zus hauv cov ntawv dawb yuav dhau los ua tib qhov rov ua ntu zus hauv cov ntawv cipher-ntawv, thiab qhov no tuaj yeem ua rau muaj kev txhawj xeeb txog kev nyab xeeb. Nrov block ciphers yog DES (Data Encryption Standard) thiab AES (Advanced Encryption Standard).
Dab tsi yog qhov sib txawv ntawm Kev Tshaj Tawm Cipher thiab Block Cipher?
Txawm hais tias ob qho tib si kwj ciphers thiab thaiv ciphers yog tsev neeg ntawm kev sib xyaw encryption ciphers, muaj qee qhov sib txawv tseem ceeb. Thaiv cov ntawv ciphers encrypt ntev ntev blocks ntawm cov khoom, thaum cov kwj ciphers muab cov ntawv sau yooj yooj yim nrog cov pseudorandom cipher cov kwj siv XOR ua haujlwm. Txawm hais tias thaiv ciphers siv tib qhov kev hloov pauv, kwj ciphers siv ntau qhov kev hloov pauv raws li lub xeev ntawm lub cav. kwj ciphers feem ntau ua nrawm dua li thaiv ciphers. Nyob rau hauv cov nqe lus ntawm hardware complexity, kwj ciphers yog kuj tsis complex. kwj ciphers yog qhov kev nyiam tshaj plaws ntawm cov ntawv ciphers thaum cov ntawv dawb muaj nyob rau hauv ntau qhov sib txawv (piv txwv li kev sib txuas wifi ruaj ntseg), vim tias thaiv ciphers tsis tuaj yeem ua haujlwm ncaj qha ntawm cov blocks luv dua qhov thaiv qhov loj. Tab sis qee zaum, qhov sib txawv ntawm cov kwj ciphers thiab thaiv ciphers tsis meej heev. Yog vim li cas yog tias, thaum siv qee hom kev ua haujlwm, lub block cipher tuaj yeem siv los ua tus kwj cipher los ntawm kev tso cai rau nws nkag mus rau cov ntaub ntawv tsawg tshaj plaws ntawm cov ntaub ntawv muaj.
