WELCOME
ICT CLASS TO
ICT FOR XI-XII
CHAPTER 6: DATABASE (PART 8) TOPIC: DEGREE OF RELATIONSHIP,
DATA SECURITY & ENCRYPTION
MONIR AHMED
ASST PROF, DEPT OF ICT
BAF SHAHEEN COLLEGE DHAKA
wi‡jkbwkc wWwMÖ (Degree of Relationship)
†WUv‡eR wi‡jkbwkc ˆZwi Kivi Rb¨ e¨eüZ GbwUwU ev †Uwe‡ji †gvU msL¨v‡K wi‡jkbwkc wWwMÖ ejv nq|
wi‡jkbwkc wWwMÖ mvaviYZ 3 cÖKvi| †hgb-
1. wWwMÖ-1 ev BDbvwi wi‡jkbwkc (Unary relationship)
2. wWwMÖ-2 ev evBbvwi wi‡jkbwkc (Binary relationship) Ges 3. wWwMÖ-3 ev Uvibvwi wi‡jkbwkc (Ternary relationship) |
wWwMÖ-1 ev BDbvwi wi‡jkbwkc (Unary relationship)
GKwUgvÎ GbwUwU ev †Uwe‡ji g‡a¨ e¨eüZ wi‡jkbwkc‡K wWwMÖ-1 ev BDbvwi wi‡jkbwkc e‡j|
One to One wKsev One to Many wi‡jkbwk‡ci g‡a¨ GB ai‡bi BDbvwi wi‡jkbwkc wWwMÖ n‡Z cv‡i| GKwU cÖwZôv‡bi Employee ev Manager †Uwe‡ji mv‡_ wb‡Ri GbwUwU ev wb‡Ri
†Uwe‡ji wi‡jkbwkc n‡”Q BDbvwi|
wWwMÖ-2 ev evBbvwi wi‡jkbwkc (Binary relationship)
`yBwU GbwUwU ev †Uwe‡ji g‡a¨ e¨eüZ wi‡jkbwkc‡K wWwMÖ-2 ev evBbvwi wi‡jkbwkc e‡j| GKwU cÖwZôv‡bi Manager GbwUwUi mv‡_ Employee GbwUwUi g‡a¨ wi‡jkbwkc n‡”Q evBbvwi|
wWwMÖ-3 ev Uvibvwi wi‡jkbwkc (Ternary relationship)
wZbwU GbwUwU ev †Uwe‡ji g‡a¨ e¨eüZ wi‡jkbwkc‡K wWwMÖ-3 ev Uvibvwi wi‡jkbwkc e‡j|
GKwU cÖwZôv‡bi Salesman, Product I Customer †Uwej 3wUi ga¨Kvi wi‡jkbwkc n‡”Q Uvibvwi|
K‡c©v‡iU †WUv‡e‡Ri (CORPORATE DATABASE)
K‡c©v‡iU †WUv‡e‡Ri n‡jv GKwU eûgyLx †WUv‡eR ev eûgzLx †WUv mwjDkb| GwU wewfbœ
gvwëb¨vkbvj †Kv¤úvwb¸‡jv Zv‡`i bvbvgyLx Kvh©µg cwiPvjbvi Rb¨ e¨envi K‡i| GwU e¨eüZ nq BbdigW BKzBwU f¨vjy‡qkb, K¤úv‡iwUf A¨vbvjvBwmm Ges †Kv¤úvwbi wewb‡qvM, jvf-ÿwZ, fwel¨r Dbœqb cwiKíbv cÖYqb cÖf…wZ Kv‡Ri| Gi gva¨‡g GKwU †Kv¤úvwbi wewfbœ †`‡k Aew¯’Z kvLv Awdm¸‡jv Zv‡`i K‡c©v‡iU †jb‡`b NwU‡q _v‡K|
K‡c©v‡iU †WUv‡e‡Ri (CORPORATE DATABASE)
▪ MÖvnK‡`i †iKW© msiÿY I wbixÿY Ges wewfbœ ˆewk‡ó¨i wfwˇZ MÖvnK‡`i †kªwYweb¨vm Kiv|
▪ wewfbœ cÖKvi F‡Yi wnmve msiÿY I cÖwµqvKiY|
▪ wewfbœ cÖKvi gy`ªvi wewbgq nvi mgš^q I nvjbvMv`KiY|
▪ †µwWU wjwgU, e¨v‡jÝ A_ev †h‡Kv‡bv Z_¨ hvPvBKiY|
▪ AbjvBb e¨vswKs I †gvevBj e¨vswKs Kvh©µg m¤cwK©Z Z_¨ msiÿY|
▪ AvšÍte¨vsK I †K›`ªxq e¨vsK †jb‡`b Kvh©µg msiÿY|
▪ ATM Kv‡W©i gva¨‡g †jb‡`b cÖwµqvKiY|
▪ evrmwiK Avq-e¨q Ges AwWU m¤cwK©Z wi‡cvU© cÖ¯‘ZKiY|
▪ MÖvnK‡`i wnmve weeiYx I Uªv݇RKkb weeiYx cÖ¯‘ZKiY|
▪ Avg`vwb-ißvwb I ˆe‡`wkK evwYR¨ msµvšÍ Z_¨ msiÿY|
▪ A_©‰bwZK wewfbœ Kvh©µ‡gi weeiYx cÖ¯‘ZKiY|
▪ gvSvwi I e„nr wkí D‡`¨v³v‡`i wkí ¯’vcb I FY cÖ`vb m¤cwK©Z Z_¨ msiÿY|
miKvwi cÖwZôv‡b †WUv‡eR
†Kv‡bv cÖwZôv‡bi A_© msµvšÍ wnmve msiÿY wKsev A_©‰bwZK cÖwZôv‡bi †ÿ‡Î †WUv‡e‡Ri e¨envi AZ¨vewk¨K| cÖwZôvb eo wKsev †QvU †nvK bv †Kb †mLv‡b A‡_©i †jb‡`b wKsev Z_¨
wewbgq I cÖwµqvKiY _vK‡eB| GB Kvi‡YB ïiæ †_‡KB cÖwZwU Z‡_¨i wnmve msiÿY K‡i ivLv AZ¨šÍ cÖ‡qvRbxq| D`vniY wnmv‡e ejv hvq, †kqvi evRv‡i †jb‡`‡bi Kv‡R e¨eüZ †WUv‡eR|
▪ bvMwiK‡`i bvg, wVKvbv, eqm, †ckv cÖf…wZ †iKW© msiÿY|
▪ evwoi †nvwìs b¤^i, f‚wg U¨v·, AvqKi, †dvb b¤^i msiÿY|
▪ we`y¨r, M¨vm, cvwb, ‡Uwj‡dvb BZ¨vw` we‡ji wnmve msiÿY|
▪ wkÿvi nvi, cv‡mi nvi, wkÿv cÖwZôv‡bi msL¨v BZ¨vw` msiÿY|
▪ miKvwi wewfbœ bw_cÎ I Rwic msµvšÍ †iKW© msiÿY|
▪ kni ev MÖvgvÂjwfwËK, †Rjv, _vbv ev GjvKvIqvix wewfbœ Z_¨ msiÿY|
▪ mvgwiK evwnbxi f‚wg, ˆmb¨, hy× miÄvg I Acv‡ikb msµvšÍ Z_¨ msiÿY|
▪ miKvwi-†emiKvwi Avq-e¨q, ivR¯^ ev Dbœqb eivÏ, ev‡RU cÖf…wZ Kv‡R|
▪ †gvU Drcv`b, evwl©K wRwWwc, Mo Avq, we‡`wk F‡Yi cwigvY cÖf…wZ wbiƒcY I msiÿY|
▪ ÷K gv‡K©‡U †kqvi `i, †Kv¤cvwb †cÖvdvBj, †Kv¤cvwb cÖm‡c±vm, m~PK cÖf…wZ wbY©q I msiÿY|
▪ wµwgbvj ev mš¿vmx‡`i †iKW©, Aciva I `~N©Ubvi cwimsL¨v msiÿY|
▪ AvqKi, Kv÷g, Avg`vwb-ißvwb, †iwgU¨vÝ cÖf…wZ msiÿY|
▪ cwimsL¨vb ey¨‡iv, wbe©vPb Kwgkb, e¨vb‡eBm cÖf…wZ cÖwZôv‡b Z_¨ cÖwµqvKiY I msiÿY|
▪ Av`gïgvwi, K…wlïgvwi, A_©‰bwZK msµvšÍ Z_¨ msiÿY|
▪ Rb¥-g„Zz¨nvi wbY©q, wewfbœ †ivMRwbZ Kvi‡Y ev gnvgvix‡Z g„Zy¨i cwimsL¨vb ‰Zwi I msiÿY|
▪ AvBb-Av`vjZ, gvgjv, Aa¨v‡`k BZ¨vw` msµvšÍ †iKW© msiÿY|
miKvwi cÖwZôv‡b †WUv‡e‡Ri e¨envi
†WUv wmwKDwiwU (Data Security)
†WUv †h‡Kv‡bv cÖwZôv‡bi LyeB ¸iæZ¡c~Y© welq Ges A‡bK †ÿ‡ÎB †WUvi †MvcbxqZv Riæix|
†mB †ÿ‡Î Abvw`©ó (Unauthorized) e¨w³ KZ©„K †Mvcbxq †WUv e¨envi DwPZ bq| †WUv‡eR A¨vWwg‡b‡÷ªUi †WUvi †MvcbxqZv iÿv Kivi `vwqZ¡ cvjb K‡i _v‡Kb| †WUv‡eR
A¨vWwg‡b‡÷ªUi †WUv‡eR e¨env‡ii Rb¨ wewfbœ e¨enviKvix‡K wewfbœ ch©v‡qi A¨vK‡mm myweav w`‡q _v‡Kb| †WUv KwgDwb‡Kk‡bi †ÿ‡ÎI †WUvi wbivcËv AZ¨šÍ ¸iæZ¡c~Y© welq|
†WUv wmwKDwiwUi mv‡_ m¤cK©hy³ welqmg~n:
▪
†cøBb †U·U (Plain Text)
▪
mvBdvi †U·U (Cipher Text)
▪
†WUv Gbwµckb (Data Encryption)
▪
†WUv wWwµckb (Data Decryption)
▪
wµc‡UvMÖvwd (Cryptography)
▪
wWwRUvj wmM‡bPvi (Digital Signature)
▪
wWwRUvj Gb‡fjc (Digital Envelop)
†cøBb †U·U (Plain Text)
we‡kl †Kv‡bv c×wZ ev †cÖvMÖvg QvovB †h †WUv, †U·U ev welqe¯‘ mn‡R cov I eySv hvq, Zv‡K †cøBb †U·U (plain text) ev wK¬qvi †U·U (clear text) e‡j| †WUvi wbivcËv eRvq ivLv I Abyb‡gvw`Z e¨envi †iva Kivi Rb¨ †cøBb †U·U‡K wewfbœ A¨vjMwi`g ev
c×wZ cÖ‡qvM K‡i GbwµÞ Kiv nq|
mvBdvi‡U·U (Ciphertext)
†h †WUv, †U·U ev welqe¯‘ `~‡e©va¨ A_©vr mn‡R cov ev eySv hvq bv, Zv‡K mvBdvi‡U·U
(ciphertext or cyphertext) ev Gbwµ‡ÞW †U·U (encrypted text) e‡j| †WUvi wbivcËv eRvq ivLv I Abyb‡gvw`Z e¨envi †iva Kivi Rb¨ †cøBb †U·U‡K GbwµÞ A_©vr `~‡e©va¨
†WUvq iƒcvšÍi Kiv nq| mvBdvi‡U·‡Ui A_© ev welqe¯‘ eySvi Rb¨ A_©vr mvBdvi‡U·U‡K cybivq
†cøBb †U·‡U iƒcvšÍi Kivi Rb¨ A¨vjMwi`g ev we‡kl c×wZ e¨envi Kiv nq|
†WUv Gbwµckb (Data Encryption)
†h we‡kl c×wZ‡Z †Kv‡bv †WUv, †U·U ev wjwLZ welqe¯‘‡K Ggbfv‡e cwieZ©b Kiv nq, hv Aci †Kv‡bv c×wZ ev †cÖvMÖv‡gi e¨envi e¨ZxZ D³ †WUv, †U·U ev welqe¯‘ cov wKsev eySv hvq bv, †m c×wZ‡K Gbwµckb ejv nq|
GbwµÞ (encrypt) Kiv †WUv Ab¨ †Kv‡bv Abvw`©ó e¨w³ eyS‡Z ev e¨envi Ki‡Z cv‡i bv|
Gi d‡j †WUvi Abyb‡gvw`Z e¨envi I wbivcËv eRvq _v‡K|
†WUv wWwµckb (Data Decryption)
†h we‡kl c×wZ‡Z †Kv‡bv mvBdvi †U·U ev Gbwµc‡UW †WUv‡K cwieZ©b K‡i c~‡e©i g‡Zv †c- Bb †U·U ev wK¬qvi †U·‡U iƒcvšÍi Kiv nq, †m c×wZ‡K †WUv wWwµckb (Data Decryption)
ejv nq| †WUv‡K wWwµÞ Kivi d‡j cÖvcK †WUvi A_© I welqe¯‘ mn‡R co‡Z I eyS‡Z cv‡i|
Drm ev †cÖiK †WUv‡K GbwµÞ Ki‡j MšÍe¨ ev cÖvcK Gbwµ‡ÞW †WUv e¨env‡ii c~‡e© wWwµÞ (decrypt) K‡i wb‡Z nq| A_©vr †WUvi wbivcËvi Rb¨ e¨eüZ †KvW‡K Aegy³ Ki‡Z nq|
wµc‡UvMÖvwd (Cryptography)
wµc‡UvMÖvwd (Cryptography) n‡”Q weÁv‡bi GKwU D”PZi kvLv †hLv‡b †WUvi wbivcËv,
†WUv Gbwµckb, wWwµckb cÖf…wZ wb‡q M‡elYv Kiv nq| G‡K A‡bK mgq wµ‡ÞvjwR
(Cryptology) e‡j| wµc‡UvMÖvwd g~jZ dwjZ MwYZ, Kw¤cDUvi weÁvb I B‡jKwUªK¨vj BwÄwbqvwis‡qi Gi mgš^‡q MwVZ GKwU kvLv, †hLv‡b †WUvi wbivcËvi welq QvovI †WUvi
†MvcbxqZv, †WUvi Bw›UwMÖwU ev ALÐZv, †WUvi mZ¨Zv ev cÖgvYxKiY, †WUvi mve©Rbxb MÖnY‡hvM¨Zv cÖf…wZ w`K wb‡q we‡kølY I M‡elYv Kiv nq|
wWwRUvj wmM‡bPvi (Digital Signature)
wWwRUvj wmM‡bPvi (Digital Signature) ev wWwRUvj ¯^vÿi n‡”Q †Kv‡bv †g‡mR, mdUIq¨vi ev wWwRUvj WKz‡g‡›Ui mZ¨Zv I ˆeaZv hvPvB Ges mwVK †cÖiYKvix kbv³ Kivi GK ai‡bi MvwYwZK
†KvW| GwU wjwLZ wmM‡bPvi ev ¯^vÿ‡ii g‡ZvB KvR K‡i| wWwRUvj wmM‡bPvi e¨env‡ii d‡j GKRb B-†gBj †cÖiYKvix KL‡bvB Zvi †cÖwiZ †gBj‡K A¯^xKvi Ki‡Z cv‡i bv wKsev Ab¨‡KD Zvi †g‡mR cwieZ©b Ki‡Z cv‡i bv|
wWwRUvj Gb‡fjc (Digital Envelop )
wWwRUvj Gb‡fjc (Digital Envelop) GK ai‡bi wbivc` B‡jKUªwbK e¨e¯’v, hv Gbwµckb I Z_¨
cÖgvYxKi‡Yi gva¨‡g A_©vr Z‡_¨i Drm I gvwjKvbv wbwðZKi‡Yi gva¨‡g †WUv‡K `yB ¯Í‡ii wbivcËv cÖ`vb K‡i| GB c×wZ‡Z e¨enviKvix wm‡µU Kx Gbwµck‡bi MwZ Ges cvewjK Kx Gbwµck‡bi myweav I wbivcËv Abymv‡i †Kv‡bv †WUv‡K Gbwµckb Ki‡Z cv‡i| cÖ_‡g evZ©v wb‡RB cÖwZmg
Gbwµckb Abymv‡i Gb‡KvW Kiv nq| Zvici cvewjK Kx Gbwµckb e¨envi K‡i wW‡KvWK…Z
†WUv‡K GbwµÞ Kiv nq| A_©vr GwU e¨enviKvix‡K `yB ¯Íiwewkó wbivcËv myweav w`‡q _v‡K|
cÖvB‡fU Kx (Private Key)
cÖvB‡fU Kx (Private Key) †Kv‡Wi GKwU ÿz`ªZg Ask, hv Z‡_¨i Drm I mwVKZv wbwðZ nIqvi Rb¨ cÖvcK KZ©„K †WUv‡K wWwµÞ Kiv A_©vr cVb‡hvM¨ di‡g‡U iƒcvšÍi Kivi †ÿ‡Î e¨envi Kiv nq| †WUv Gbwµckb I wWwµckb A¨vjMwi`g †mU Kivi Kv‡R A_v©r Z_¨‡hvMv‡hv‡Mi KvR
myiwÿZ Kivi Rb¨ GwU cvewjK Kx‡qi mv‡_ †RvUe× n‡q e¨envi Kiv nq| cÖvB‡fU Kx‡K A‡bK mgq wm‡µU Kx (Secrete Key) ejv nq|
cvewjK Kx (Public Key)
cvewjK Kx (Public Key) n‡”Q GKwU e„nr msL¨vhy³ gvb, hv Z_¨ †hvMv‡hv‡Mi KvR myiwÿZ
Kivi Rb¨ †WUv‡K GbwµÞ Kiv A_©vr †cøBb †U·U‡K mvBdvi †U·‡U iƒcvšÍi Kivi Kv‡R e¨envi Kiv nq| cvewjK Kx Gbwµckb wµ‡ÞvMÖvwd‡Z cvewjK Kx ˆZwi Kiv nq, hv AcÖwZmg-Kx
Gbwµckb A¨vjMwi`g e¨envi K‡i †Kv‡bv †cøBb †U·U ev †evaMg¨ †WUv‡K wWwµÞ Kiv ev mvBdvi †U·‡U iƒcvšÍi Kiv A_©vr AcVb‡hvM¨ di‡g‡U cwieZ©b Ki‡Z e¨envi Kiv nq|
†WUv Gbwµckb I wWwµckb Kv‡R e¨eüZ A¨vjMwi`g ev c×wZ‡K wµ‡ÞvMÖvwdK A¨vjMwi`g
e‡j| wewfbœ ai‡bi wµ‡ÞvMÖvwdK A¨vjMwi`‡gi g‡a¨ RbwcÖq K‡qKwU A¨vjMwi`‡`i bvg wb‡P †`qv n‡jv-
▪ Caesar Cipher,
▪ IDE-International Data Encryption Algorithm,
▪ Hash,
▪ DES-Data Encryption Standard (DES),
▪ Triple DES,
▪ RSA-Ron Rivest, Adi Shamir Ges Leonard Adleman,
▪ Blowfish,
▪ Twofish,
▪ AES-Advanced Encryption Standard (AES),
wµ‡ÞvMÖvwd A¨vjMwi`g (Cryptographic Algorithm)
†WUv Gbwµckb Kivi c×wZ¸‡jvi g‡a¨ me‡P‡q †ewk e¨eüZ n‡jv Caesar Code c×wZ| †ivgvb m¤ªvU Julius Caesar Gi bvg
†_‡K Caesar bvgwU G‡m‡Q| Julius Caesar †Kvb †Mvcbxq wPwV ev Ab¨ †Kvb wb‡`©k (hv kµc‡ÿi n¯ÍMZ n‡j iv‡óªi ÿwZ n‡Z cv‡i) cvVv‡bvi mgq wPwV ev wb‡`©‡ki Aÿi¸‡jv‡K wbw`©ó msL¨K Ni Wv‡b ev ev‡g ¯’vbvšÍwiZ K‡i cvVv‡Zb|
eZ©gv‡b †WUv cvVv‡Z Caesar Code Gbwµckb c×wZi wewfbœ iKg A¨vjMwi`g e¨envi Kiv nq| G‡ÿ‡Î †cÖwiZ ev M„nxZ †WUv‡K Plain Text Ges Gbwµc‡UW †WUv‡K Cipher Text ev `y‡e©va¨
welqe¯‘ ejv nq|
Gbwµckb c×wZ: Caesar Code
Gbwµckb c×wZ: Caesar Code
GKBfv‡e †Kv‡bv eY©‡K 3 Ni ev‡g wKsev 23 Ni Wv‡b wkdU Ki‡j Cipher †U·U nq-
Plain: ABCDEFGHIJKLMNOPQRSTUVWXYZ Cipher: XYZABCDEFGHIJKLMNOPQRSTUVW
Plaintext: THE QUICK BROWN FOX JUMPS OVER THE LAZY DOG Ciphertext: QEB NRFZH YOLTK CLU GRJMP LSBO QEB IXWV ALD
A B C D E F ....
Z Y
X
D E F G H I C
B A
....
†hgb- †Kv‡bv eY©‡K 3 Ni Wv‡b wkdU Ki‡j Cipher †U·U nq-
G‡mv wb‡R‡K hvPvB Kwi: ˆbe©¨w³K cÖkœ
1| Uvibvwi wi‡jkb KqwU GbwUwU ev †Uwe‡ji g‡a¨ msNwUZ nq?
K. 1wU L. 2wU M. 3wU N. 4wU
2| Abyb‡gvw`Z e¨w³ KZ©„K †WUv A¨v‡·m †iva Kivi mv‡_ †Kvb welqwU mivmwi m¤úK©hy³?
K. †WUv cÖ‡mwms L. †WUv gvBwbs M. †WUv wmwKDwiwU N. †WUv †fwj‡Wkb 3| †WUv wmwKDwiwUi Rb¨ †evaMg¨ †WUv‡K `~‡e©va¨ †WUvq iƒcvšÍ‡ii cÖwµqv‡K Kx e‡j?
K. †WUv BbwU‡MÖkb L. †WUv †fwj‡Wkb M. †WUv Gbwµckb N. †WUv wWwµckb
4| †WUv wmwKDwiwU, †WUv Gbwµckb I †WUv wWwµckb wb‡q M‡elYvi welq Kx bv‡g cwiwPZ?
i. Cryptography ii. Cryptology iii. Cryptarithm
†KvbwU mwVK?
K. i, ii L. i, iii M. ii, iii N. i, ii, iii
5| `yB ¯Íiwewkó wbivcËvi Rb¨ †Kvb c×wZ e¨envi Kiv nq?
K. cÖvB‡fU Kx L. cvewjK Kx M. wWwRUvj wmM‡bPvi N. wWwRUvj Gb‡fjc
