G. RAMESH AD R. UMARAI: DATA SECURITY I LOCAL AREA ETWORK BASED O FAST ECRYPTIO ALGORITHM DATA SECURITY I LOCAL AREA ETWORK BASED O FAST ECRYPTIO ALGORITHM G. Ramesh and R. Umaran Department of MCA, Thruvalluvar College of Engneerng and Technology, Taml adu, Inda Emal: mgrameshmca@yahoo.com Department of Computer Scence, Sr Sarada College for Women, Salem, Taml adu, Inda Emal: umanweb@gmal.com Abstract Hackng s one of the greatest problems n the wreless local area networks. Many algorthms have been used to prevent the outsde attacks to eavesdrop or prevent the data to be transferred to the end-user safely and correctly. In ths paper, a new symmetrcal encrypton algorthm s proposed that prevents the outsde attacks. The new algorthm avods key exchange between users and reduces the tme taken for the encrypton and decrypton. It operates at hgh data rate n comparson wth The Data Encrypton Standard (DES), Trple DES (TDES), Advanced Encrypton Standard (AES-56), and RC6 algorthms. The new algorthm s appled successfully on both text fle and voce message. Keywords: Plantext; Encrypton, Decrypton, S-Box, Key-updatng, Outsde attack. ITRODUCTIO Wreless Local Area etwork (WLA) s one of the fastestgrowng technologes. The demand for connectng devces wthout the use of cables s ncreasng everywhere. WLA s found n the offce buldngs, and n many other publc areas []. The securty n WLA s based on cryptography, the scence and art of transformng messages to make them secure and mmune to attacks by authentcatng the sender to recever wthn the WLA. The cryptography algorthms are dvded nto two groups: symmetrc-encrypton algorthms and asymmetrc-encrypton algorthms. There are a lot of symmetrc-encrypton algorthms used n WLA, such as DES [], TDES [3], AES [4], and RC6 [5]. In all these algorthms, both sender and recever have used the same key for encrypton and decrypton processes respectvely. The outsde attackers use the fxed plantext (such as: the company-ttle whch s sent n the frst packets of the message) and encrypted text to obtan the key used n the WLA. A new symmetrcal encrypton algorthm s proposed n ths paper. The new algorthm avods fxed-key exchange between sender and recever wth each authentcaton process n WLA. The paper s organzed as follows. Secton gves a short revew of the symmetrcal-encrypton algorthms. Secton 3 presents the proposed algorthm. Secton 4 shows the results. Fnally, Concluson are presented n Secton 5.. REVIEW O THE SYMMETRICAL- ECRYPTIO ALGORITHMS There s a lot of the symmetrcal-encrypton algorthms used n WLA. DES [], known as Data Encrypton Algorthm (DEA) by the ASI [6] and the DEA- by the ISO [6] remaned a worldwde standard for very long tme and was replaced by AES on October 000. DES provdes a bass for the comparson of new algorthms. It s a block cpher symmetrc algorthm that uses the same key for both encrypton and decrypton. The basc buldng block (a substtuton followed by a permutaton) s called a round and s repeated for 6 tmes []. The substtutons process depends on the S-Box. S-Box s a matrx of 4 rows and 6 columns. DES has 8 dfferent S-Boxes n each round. S-Box s used to map the nput code to another code to the output. The nput code specfes the output code poston n ths S-Box. The frst and last bts specfy the row number, and the rest bts specfy the column number. The permutaton tables are used for changng the bt-orders n the packet. For each DES round, a sub-key s derved from the orgnal key usng an algorthm called key schedule whch s the same for encrypton and decrypton except for the mnor dfference n the order (reverse) of the sub-keys for decrypton. In the encrypton process, DES encrypts the data n 64-bt blocks usng a 64-bt key (although ts effectve key length n realty s only 56-bt). TDES s a block cpher formed from the DES cpher by usng t three tmes. When t was found that a 56-bt key of DES s not enough to guard aganst brute force attacks, TDES was chosen as a smple way to enlarge the key space wthout the need to swtch to a new algorthm. The smplest varant of TDES encrypton operates as follows: DES(k3;DES-(k;DES(k;M))), where M s the message block to be encrypted, k, k, and k3 are DES keys, and DES and DES- refer to the encrypton and decrypton modes respectvely. Whle the TDES decrypton operates as follows: DES-(k; DES (k; DES-(k3; C))), where C s the cpher text block. AES algorthm s a symmetrc block. It s used to encrypt and decrypt the plantext and cpher text of 8-bts respectvely by usng cryptographc keys of 8-bts (AES-8), 9-bts (AES- 9), or 56-bts (AES-56). The number of rounds n the encrypton or decrypton processes depends on the key sze. RC6 s more accurately specfed as RC6-w/r/b where the word sze s w bts, encrypton conssts of a nonnegatve number of rounds r, and b denotes the length of the encrypton key n bytes. Snce the AES submsson s targeted at w = 3 and r = 0, RC6 shall be used as shorthand to refer to such versons. When any other value of w or r s ntended n the text, the parameter values are specfed as RC6-w/r. Of partcular relevance to the AES effort s the versons of RC6 wth 6-, 4-, and 3-byte keys. The complexty of the algorthm and the key sze enhance the data securty n WLA, and they ncrease the dffculty to the attackers to dscover the orgnal message. The new algorthm adds some dffcultes to the attackers to dscover the key. These dffcultes are The longer key sze, 5-bts, compared wth DES, TDES, AES-56, and RC6. 8
ICTACT JOURAL O COMMUICATIO TECHOLOGY, JUE 00, ISSUE: 0 The key-updatng wth each packet. The new symmetrcal algorthm s appled on a text message and voce message. The comparson between the plan text and the decrypted text s easer than voce message. The two approaches used for measurng speech qualty are the subjectve and the objectve approaches [8]. Subjectve measures assess speech qualty based on the perceptual ratngs by a group of lsteners [9]. Objectve measures assess speech qualty usng the physcal parameters [0]. The physcal parameters are calculated from equatons (,, 3, and 4). x ( ) = SR = 0 Log0 () ( x( ) y( )) = + 0 M m x ( ) SRseg = Log 0 () M m= 0 = m ( x( ) y( )) axryax Log ayryay = T T LLR (3) + M m SD = Vx( ) Vy( ) (4) M m= 0 = m where: SR s the sgnal-to-nose rato [0], x() and y() are the orgnal and decrypted speech respectvely, s the total number of samples n both encrypted and decrypted speech sgnals, M s the number of segments n the speech sgnals, LLR s the Lkelhood Rato [0], ax and ay are the Lnear Predctve Codng (LPC) for the orgnal and decrypted speech sgnals respectvely, Ry s the autocorrelaton matrx for the decrypted speech sgnal, SD [0] s Spectral Dstorton, and Vx() and Vy() are the spectrum of the orgnal and the decrypted speech sgnals respectvely n db for a certan segment n tme doman. Correlaton [] s a measure of the relatonshp between two varables. If the two varables are In perfect correlaton, then the correlaton coeffcent (C.C) equals one. Hghly dependent (dentcal), In ths case the encrypted data s the same as the orgnal data and the encrypton process faled n hdng the detals of the orgnal data. If the C.C equals zero, then the orgnal data and ts encrypton are totally dfferent,.e., the encrypted data has no features and hghly ndependent on the orgnal data. If C.C equals (-), ths means the encrypted data s the negatve of the orgnal data. So, the success of the encrypton process means smaller values of the C.C. The C.C s measured by the followng equaton: ( x E( x))( y E( y)). = = (5) ( x E( x)) ( y E( y)) = = CC where: E x) = x = (, and x and y are values of the orgnal and encrypted data. 3. THE EW SYMMETRICAL ALGORITHM The new algorthm uses a key sze of 5-bts to encrypt a plantext of 5-bts durng the 6-rounds. In ths Algorthm, a seres of transformatons have been used dependng on S-BOX, dfferent shft processes, XOR-Gate, and AD-Gate. The S-Box s used to map the nput code to another code at the output. It s a matrx of 6 x 6 x 6. The S-Box conssts of 6-sldes, and each slde havng -D of 6 x 6. The numbers from 0 to 55 are arranged n random postons n each slde. The S-Box s generated accordng to the flowchart of Fg.. Each slde n the S- Box s descrbed by the followng equaton: S X Y = S X Y (6) where =,,,6, and s defned as the round number used n the key-generaton, encrypton, and the decrypton processes. So, the frst round operates on the frst slde, S = S, and the second round operates on the second slde, S = S, and so on. For example, f the nput 5A, n the hexadecmal form, s appled on the S-Box n round number, then S = S = S. Let S X Y have the contents of Table.. The output code takes the row number 5 and column number A, or the output code s ED. 3.. KEY GEERATIO The key generaton generates 6-keys durng 6-rounds. One key of them s used n one round of the encrypton or decrypton process. In the frst tme, the ntal key s dvded nto four parts a, b, c, and d, 8-bts each. In each round of the key generaton, there are seres of the transformaton used to generate the roundkey. The round-key conssts of four parts a*, b*, c*, and d*, and t s used n the same round order to encrypt to the data, see Fg.. The procedures of the key-generaton are as the followng: Step : Dvde the ntal key nto four parts a, b, c, and d, 8-bts each. For example, Let the ntal key be, BC07FE3F9507555D8DB639D078BD6F5D35EBCE A767C7334D3A034F0D6CEEDB8ABA8DE3795F3 50F5B4DF06BC54DB4585EE4538A33879CFCF4E F Thus, a= BC07FE3F9507555D8DB639D078BD6 b= F5D35EBCEA767C7334D3A034F0D6 c= CEEDB8ABA8DE3795F350F5B4DF06BC d= 54DB4585EE4538A33879CFCF4EF 9
G. RAMESH AD R. UMARAI: DATA SECURITY I LOCAL AREA ETWORK BASED O FAST ECRYPTIO ALGORITHM Step : a* = a b a*=934d4a0837f739eb96599e4676b7 Step 3: Horzontal Left-Shft (Crcular Shft) The c-part s rearranged to a matrx form of 4*4, and each element of the matrx appears as two hexadecmal numbers. o shft n the frst row. The second, thrd, and forth row s left-shfted by one, two, three elements (crcular shft) respectvely. c= CE A 95 B4 CE A 95 B4 8D F3 DF ED ED 8D F3 DF h= 50 06 B8 E3 B8 E3 50 06 BC AB 7 F5 Step 4: b*=m= S ( h) AB 7 F5 BC h, s mapped nto another code by applyng S-Box on h to have m at the output. Each round uses one slde from S- Box accordng to the round number, where =,,,6, as dscussed later. Let S X Y have contents of Table., thus b* s obtaned as the followng: 57 F E9 94 8 4 0 D 85 C8 3C 6A 5 9 8A 5 b*=578855f4c89e903c8a94d6a5 Step 5: Vertcal Upper-Shft (Crcular Shft) Step 6: The d-part s rearranged to a matrx form of 4*4, and each element of the matrx appears as two hexadecmal numbers. o shft n the frst column. The second, thrd, and forth column s upper-shfted by one, two, three elements (crcular shft) respectvely. d= Step 7: d*=a 54 EE 3 CF 54 45 9 F DB 45 87 4E w= DB 38 CF CF 45 38 9 45 A3 3 4E 85 A3 CF F 85 EE 87 c* = m w c*=359c0a0b77a6b7f7bcd0d0dbbe404 d*=bc07fe3f9507555d8db639d078bd6 Thus, the round key conssts of four parts a*, b*, c*, and d*, or K=934D4A0837F739EB96599E4676B7578855F 4C89E903C8A94D6A5359C0A0B77A6B7F7BCD0 D0DBBE404BC07FE3F9507555D8DB639D078BD 6. Step 8: Repeat the prevous steps 5-tmes to obtan the 6-keys used to encrypt or decrypt the data. 3. ECRYPTIO The Encrypton process n the new algorthm s used to encrypt the plantext of sze of 5-bts by a key of sze of 5-bts n each round durng 6-rounds. Seres of transformatons are appled on the plantext n each round as shown n Fg.3 to obtan a cpher text fnally. The encrypton procedures are as the followng: Step : Kp = Kv K where: K s the round-key that generated by the key-generaton process. s the round number, and =,,,6. Kv s the value of the feedback, as shown n the Fg.3, and ts value n the frst tme s zeroes n all ts 5-bts. Step : Kp = S ( Kp) Kp s rearranged nto a matrx format of8 8, and each element has two hexadecmal numbers, as descrpt n the key-generaton procedures. Then, Kp s appled on one slde of the S-Box accordng to the round number to produce Kp. Kp s a 5-bts key. It s used to update the total key used to encrypt the data wth each packet dependng on the feedback as shown n Fg.3. Kp value s backed to AD wth Rv to obtan Kv, see equaton (7). Kv = Kp Rv (7) where, Rv s a 5-bts key, and all bts are one. It s used to reset the system f the synchronzaton s lost durng the encrypton and decrypton processes due to the total keyupdatng wth each packet n each round. Step 3: Mn = S ( M ) Step 4: Ms = R(Mn) Step 5: R(Mn) s a seres of dfferent shftng drecton followed by XOR wth K, see Fg.4. The steps of R(Mn) as the followng: Frst, Horzontal Left-Shft (crcular shft), as descrpt n key-generaton process. But, the matrx becomes 8 x 8 nstead of 4 x 4. Second, Vertcal Upper-Shft (crcular shft), as descrpt n key-generaton process. But, the matrx becomes 8 x 8 nstead of 4 x 4. Thrd, the result of shft processes s XORed wth k. Mp = Ms Kp Step 6: M* = S ( Mp) Step 7: Repeat the prevous steps 5-tmes to obtan the cpher text of sze of 5-bts. 0
ICTACT JOURAL O COMMUICATIO TECHOLOGY, JUE 00, ISSUE: 0 Table.. The contents of S-Box at round, S X*Y 0 3 4 0 6E C7 0B F8 FF DF 5B D 45 E3 4 B0 3 BC 5D 3 D0 3F B A7 04 4 D3 8E 3B D F4 5 85 35 4 B5 F 6 8D 0A 7 7C 6C 7 E7 8A 36 69 8 95 F3 74 C6 EE 9 B3 64 E4 F7 E A 5F A3 A0 5 C9 B CD A 77 CA 94 C E DB 4 AB AA D C5 6 FA 7A 3E E FB 9F 6A 5 F AC E5 7 4 C0 5 6 7 8 9 A B C D 75 C8 B9 07 49 5C 7 67 FC FD 58 D CC FE AE 6F A8 B4 7B F6 5A 65 F F 44 73 EB EC 8 B 39 EA 8B 76 EA D8 F9 33 3A C DC 9A 4D 9D 9C 3 D4 8 4 79 ED 3 A6 EF D 4A E6 E8 B6 C 88 9E A5 87 E 6 0D 89 9 A9 55 D5 68 4F 40 CE 30 6B 43 8 E9 F D9 8 5 48 F5 9 A4 9 56 C 0E AC F0 9 A 7F 53 09 0C 3C 8F 3D 93 5 50 4 A 00 54 08 66 E0 06 9B CB BE BB C0 D7 8C 6 6D 4E B7 86 0 A 47 BA 0 D 5 43 D0 95 56 7B 00 0 76 E F 0F C3 70 80 D6 CF DA 90 DE 4B 63 7E E5 B B 97 78 37 0 C 60 84 3 7 57 AD 7 0 4F 6 EF D 3.3 DECRYPTIO The decrypton of the new algorthm s the same as the encrypton except: The drecton of the encrypton process s reversed, see Fg.5. The drecton of R (Mn) s reversed, see Fg.6. The shft drecton s reversed - Horzontal rght-shft nstead of left-shft - Vertcal down-shft nstead of upper-shft. 3.4 APPLICATIOS Text and voce messages are used as applcatons to prove the success of the new encrypton algorthm to encrypt and decrypt the dfferent messages. The applcaton s run nsde the WLA envronment, see Fg.7. The voce message s also appled nsde the Wred LA envronment usng the pont-to-pont connecton, see Fg.8. The proposed algorthm uses the followng:. Software Mcrosoft Vsual C# dot net program. MATLAB v7.. Hardware Desktop: Intel Pentum 4 CPU.8GHz GB of RAM LAPTOP Acer: Intel Atom CPU 70 @.60GHz GB of RAM A 54M Wreless Access Pont of TP-Lnk (TL-WA50G) A 54M Wreless USB Adapter of TP-Lnk (TL- W3G)..5 m Ethernet cable. Fg.9.a gves a plan text, and ts decrypted verson and the encrypted verson are shown n Fg.9.b and 9.c. Fg.9.d shows the other encrypted verson for the same plan text. The dfference between the two encrypted texts s cleared n Fg.9.c and 9.d. whch proves the prncple of the key-updatng. The voce encrypton and decrypton processes are appled between two computers usng wred or wreless connecton. The voce transmsson s appled usng a mcrophone at one sde, and a speaker at the other computer. The dstance between them s about.5m to mnmze the errors and the nose even f usng the wred or wreless connecton. In the wreless connecton, the orgnal voce and the decrypted voce are shown n Fg.0.a and ther spectrograms are shown n Fg.0.b and the encrypted voce and ts spectrogram are shown n Fg.0.c. In the wred connecton, the orgnal voce and the decrypted voce are shown n Fg..a and ther spectrogram are shown n Fg..b and the encrypted voce and ts spectrogram are shown n Fg..c. If >5? End Fg.. Flowchart of the S-Box Generaton S X x Y x (6x6x6)
G. RAMESH AD R. UMARAI: DATA SECURITY I LOCAL AREA ETWORK BASED O FAST ECRYPTIO ALGORITHM Fg.5. Decrypton Process n each round K6- Fg.. Key-Generaton procedures n one round Fg.6. Inverse Process of R(Mn) A 54M Wreless Access Pont of TP-Lnk (TL-WA50G) Fg.3. Encrypton Process n each round PC: LAPTOP Acer: PC: Intel(R) Pentum(R) Intel Atom CPU 4 CPU.8GHz, and GB 70 @.60GHz of RAM wth a 54M GB of RAM wth Wreless USB Adapter of Atheros AR5007EG TP-Lnk (TL-W3G). Wreless etwork Adapter Fg.7. Wreless LA (Infrastructure mode) Ethernet Cable (.5m) Fg.4. R(Mn) Steps PC: Intel(R) Pentum(R) 4 CPU.8GHz, and GB of RAM wth a 54M Wreless USB Adapter of TP-Lnk (TL-W3G). PC: LAPTOP Acer: Intel Atom CPU 70 @.60GHz GB of RAM wth Atheros AR5007EG Wreless etwork Adapter Fg.8. Wred LA (Pont-to-Pont Connecton)
嵭 搦 悓 纥 Wreless local area network (WLA) s one of the fastest-growng technologes. The demand for connectng devces wthout use of cables s ncreasng everywhere. WLA can be found on collage campus, n offce buldngs, and n many publc areas []. The securty n WLA s based on cryptography, the scence and art of transformng messages to make them secure and mmune to attack. Cryptography can be used to authentcate the sender and recever of the message to each other wthn WLA. The cryptography algorthms can be dvded nto two groups: symmetrc- encrypton algorthms and asymmetrc-encrypton encrypton algorthms. Fg.9.a. Plan Text Wreless local area network (WLA) s one of the fastest-growng technologes. The demand for connectng devces wthout use of cables s ncreasng everywhere. WLA can be found on collage campus, n offce buldngs, and n many publc areas []. The securty n WLA s based on cryptography, the scence and art of transformng messages to make them secure and mmune to attack. Cryptography can be used to authentcate the sender and recever of the message to each other wthn WLA. The cryptography algorthms can be dvded nto two groups: symmetrc- encrypton algorthms and asymmetrc-encrypton encrypton algorthms. Fg.9.b. Decrypted Text 夓 䫺 ICTACT 輭 쏷쏷쏷 嬇 䪄 橉 䪄 䪄 벰 䲞 JOURAL O 颥 跥 輘 풆 눂 랏랏 減 쯬 楍 ꄝ쭐 틐 吝 怛 竻 풗 퉀KM 節 兄 赼 榅 㗰 髜 煥 箏 뿡 ᘂ 媡 伕 퇚 嗫 炳 굗 詹 髜 忒 曒 躆 忒 ⰽ 枟 嚉 ᗨⰽ 螿 岂 嚉 綡 疥 ⰽ 㺎 COMMUICATIO TECHOLOGY, JUE 00, ISSUE: 0 薲 烙 ᅝᅝ 荊 樠 樠 ᇞ 甒 㡱 ቑ ᖋ ᕭ 꼋 缾 킯 u 礪 礤 粥 䉑 䔷 궔 ஶ 袡 틱 䔷 禨 㠲 䌾 㶞 鼴 樓 뒑뇵뇵 づ 惔 㜢 嗆 莺 맽 㘐 噵 뽇 㣕 굗 뉩 誾 嶮 秣 뽲 퓯퓯 퐲 䂢 笐 ₂ ɢ맮 景 笐 鎷 鑥 濼 㵛 욲욲 倲 奣 聂 ດ䠔 洝 䀩 秇 읍 픺 鵓 䝣 㔓 颈 㰚 츛 ꂈ 挸 녨 ꪞ 䘙 䦾 쿧 苧 き 耭 䒖 霱 똫 龲 훼 霱 余 㹝 遍 㦇 ꠟ 䡷 鐵 䐺 䋸 ꠟ 복 뷖₂ 휂휂੧ rad 쿻 櫨 鵭 䌗 舩 䎾 巔 몧 隤 茵 戹 庬 䤹 Ï ᗨ ꉇ 瀎 뮮 ᄉᄉ 茵 慥 鑭 颭 脀 檕 䟭 䢔 뤸벏 蘥 册 蘥 㢮 调 逹 䄱 㩪 茵 ꠟ 懆 寺 Ӷ 嘻 䮽 䢔 숃 寺 騷 蛶 貇 ฮ 䢔 쾐 焻 졎 ꛖ 畇 ᛔ ズ 㫢 脡 䋝 ㄿ 糞 伺 鞆 ぇ ᓴ 屚 爫 ꙧ 噀 묚Ŕ 婪 ㅹ 䘉 ᔥ ꙧ פֿ ᓠꏧꏧ 뗡 ౬ 쿉 嫈 仰 Fg.9.c. 办 橯 頦 嚄 橯 䔴 魅 䏨 滚 䏨 믧 禚 嫟 䏨 쬻 㮠 Ⰽ 躟 嫭 ⰍⰍ펵펵펵펵펵 糯 䂴 Cpher 삣삣໙㥅 ꃇ 럾 鄡 횬 ꙧ 㣷 辂 犔 辂 畇 辂 䬩 쓌ꙧ 댏댏 輠 䛑 ම 멹 ꙧlm 銚 ꙧꙧ 㮐 覟 Text صص ꊳ 曕 묣묣Ꞩ 碕 㟡 茐 ԧ 븯 三 狣 됑 圱 膣 퓛Ꞩ 獑 ウ ꙧꙧ 瑝 ꋥ 瑝 홱 翫 璧 ผ 熞 ԧ 璧 䫫 쩲 ໙ 昿 㞻 34 疨 誇 줊 醕 咵 荠 憮 됈 뼻뼻 㥀 ح ጡ 鈰 鈰 䶢 岭 됟됟ꄦ 珑 蹧 懲 蹧 懲 颴 ァ 懲 ಎ뤉 조조餰 퍖 吭 좬 赣 懲 뙩 㧝 ꊆ ⶻ ج ڃ뇍 జ ᠡ Ƽ ꎚꁎḒ 쉥 Ὣ ȉ 拁 溟 拁 揔 푌 拁 鱽 ଌ 삒삒 烬 뤔 휵 㳙 ꊛឝ ಽ ẇ 컛 ꆖ 신 駶 輡 쨥쨥 㹽 냐 㪯 踱 䠻 론눇 Fg.9.d. The other Cpher Text for the same Plan Text T ನ 吩 叕 駨 뉮뉮 旟 䯈 魨 䯈 㷎 ףּ뵡ض ⒘쨚 퓯퓯 躯 奐 疃 데 䝜 䞋 欛 뭆 쟤 棝 좹 輟 鷻 鷻 뽾 ᕂ Orgnal Sgnal Ampltude Ampltude Decrypted Sgnal Fg.0.a. The orgnal and decrypted voce (wreless connecton)
G. RAMESH AD R. UMARAI: DATA SECURITY I LOCAL AREA ETWORK BASED O FAST ECRYPTIO ALGORITHM Orgnal Sgnal Decrypted Sgnal Fg.0.b. The spectrogram of the orgnal and decrypted voce Encrypted Sgnal Ampltude Fg.0.c. The encrypted voce and ts spectrogram (wreless connecton)
ICTACT JOURAL O COMMUICATIO TECHOLOGY, JUE 00, ISSUE: 0 Orgnal Sgnal Decrypted Sgnal Fg..a. The orgnal and decrypted voce (wred connecton) Orgnal Sgnal Decrypted Sgnal Fg..b. The spectrogram of the orgnal and decrypted voce (wred connecton)
G. RAMESH AD R. UMARAI: DATA SECURITY I LOCAL AREA ETWORK BASED O FAST ECRYPTIO ALGORITHM Encrypted Sgnal Ampltude Fg..c. The encrypted voce and ts spectrogram (wred connecton) 4. THE RESULTS The data rate of the new algorthm s compared wth DES, TDES, AES-56, and RC6 usng dfferent messages wth dfferent szes, from 50KB untl 3MB, see Fg.. The delay tme taken for encrypton process of the dfferent algorthms s measured nsde ther programs by usng the DESKTOP devce for the comparson purpose, see Fg.. The Average data rate of the dfferent algorthms s calculated from equaton (8), and the measured values of the average data rate for dfferent algorthms are shown n Table.. b M Bravg = (KB/s) b t = where: Bravg s the average data rate (KB/s) b s umber of messages wth dfferent szes, from 50KB untl 3MB M s the message sze (KB) t s the tme taken to encrypt the message M Table. shows that, the new algorthm has hgher average data rate than DES, TDES, and AES-56, but the RC6 has the hgher value than the proposed algorthm. In addton, the new algorthm adds some dffcultes to the attackers to dscover the key. These dffcultes are The longer key sze, 5-bts, compared wth DES, TDES, AES-56, and RC6 The key-updatng wth each packet (8) Message Sze Average Data Rate (kb/s) Table.. Average data rates comparson AES-56 TDES 0.73 3.3 46.73 7.56 93.98 Tme (ms) ew RC6 DES Fg.. The Encrypton delay tme for the proposed, DES, TDES, AES-56, and RC6 algorthms Table.3 shows the calculated correlaton factor of the speech sgnal between the plan wave and the encrypted wave n the case of wred and wreless connecton.
ICTACT JOURAL O COMMUICATIO TECHOLOGY, JUE 00, ISSUE: 0 Table.3. The Correlaton factor n the case of the wred and wreless connecton (Speech Sgnal) Plan and Encrypted Waves Wred Connecton 0.003 Wreless Connecton -0.00 The success of the encrypton process means smaller values of the correlaton coeffcent, and f the correlaton coeffcent equals zero, then the orgnal data and ts encrypton are totally dfferent,.e., the encrypted data has no features and hghly ndependent on the orgnal data. The parameters of equatons (,, 3, and 4) are measured for new algorthm envronment n the case of wreless connecton and wred connecton, see Table.4. Thus, the system s more secure because of the followng reasons,. The new algorthm adds some dffcultes to the attackers to dscover the key. These dffcultes are The longer key sze, 5-bts, compared wth DES, TDES, AES-56, and RC6 The key-updatng wth each packet. The outsde attacks cannot obtan the key or any nformaton about the algorthm even f he had the plantext, the company ttle, S-Box, and the encrypted message because they lose the synchronzaton or the ntal key of each round where they are ndependent. In addton, the proposed algorthm has the followng advantages: The delay tme taken for the encrypton and the decrypton processes by the proposed algorthm s less than the tme taken DES, TDES, and AES-56 algorthms Hgher data rate than DES, 3DES, AES, and AES-56 algorthms The updatng of the round-key wth each packet The updatng of the round-key prevents any change n the transmtted message because t s known to the sender and the recever because of losng the synchronzaton between the encrypton and the decrypton. So t prevents the attackers such as, man-n-the mddle attacks to analyss the traffc or to decrypt the encrypted message. Table.4. The measured parameters n the case of wreless connecton and wred connecton Wreless Connecton Wred Connecton SR -3.5779-3.5093 SRseg -3.6484-3.534 LLR 0.555 0.4667 SD 4.567 4.494 5. COCLUSIO The key-updatng s a new approach to ncrease the dffculty to dscover the key. The text and speech sgnals are used to prove the success of the proposed algorthm. The proposed algorthm has hgher data rate than DES, TDES, and AES-56 algorthms. The voce encrypton and decrypton s appled usng wred and wreless connecton. It s effcent and useable for the securty n the WLA systems. REFERECES [] Wllam Stallngs, etwork Securty Essentals (Applcatons and Standards), Pearson Educaton, 004. [] Paul. A.J, Varghese Paul, P. Mythl, A FAST AD SECURE ECRYPTIO ALGORITHM FOR MESSAGE COMMUICATIO, IET-UK Internatonal Conference on Informaton and Communcaton Technology n Electrcal Scences (ICTES 007), Dr. M.G.R. Unversty, Chenna, Taml adu, Inda. December, 0-, 007. pp. 69-634. [3] Jose J. Amador, Robert W.Green, "Symmetrc-Key Block Cphers for Image and Text Cryptography", Internatonal Journal of Imagng System Technology, 005. [4] Daemen, J., and Rjmen, V. "Rjndael: The Advanced Encrypton Standard." Dr. Dobb's Journal, March 00. [5] awal A. El-Fshawy, Talat E. El-Danaf, and Osama M. Abou Zad, A MODIFICATIO OF RC6 BLOCK CIPHER ALGORITHM FOR DATA SECURITY (MRC6), Internatonal Journal of etwork Securty (IJS), 007. [6] ASI3.06, Amercan atonal Standard for Informaton Systems Data Encrypton Algorthm Modes of Operaton, Amercan atonal Standards Insttute, 983. [7] Bruce Schneder, John Wley & Sons, Inc., Appled Cryptography, Second Edton, ew York, Yaq 996. [8] D. O Shaughnessy, Speech Communcaton: human and machne, ew York Y. The Insttute of Electrcal and Electroncs Engneers, Inc., 000. [9] ITU, Methods for Subjectve Determnaton of Transmsson Qualty, ITU-T. pp. 800. 996. [0] T. Falk and W.-Y. Chan, Sngle Ended Method for Objectve Speech Qualty Assessment n arrowband Telephony Applcatons, ITU-T, pp. 563, 004. [] awal El-Fshawy and Osama M. Abu Zad, Qualty of Encrypton Measurement of Btmap Images wth RC6, MRC6, and Rjndael Block Cpher Algorthms, Internatonal Journal of etwork Securty (IJS), 007. 7