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يﺎﻫﺰﻣرنرﺎﻘﺘﻣ ﺮﺑ ﻲﻨﺘﺒﻣﻞﺼﻓ يﺎﻫ 2 ، 3 ، 4 و 5 بﺎﺘﻛ زا Network Security, Principles and Practice,3 rd Ed. ﻂﺳﻮﺗ هﺪﺷ ﺶﻳاﺮﻳو : ﺎﺿر ﺪﻴﻤﺣ يرﺎﻳﺮﻬﺷ shahriari@mehr.sharif.edu ���� ���� ����� ���� ﺐﻟﺎﻄﻣ ﺖﺳﺮﻬﻓ � ﻒﻳرﺎﻌﺗ � يﺎﻫﺰﻣر ﻚﻴﺳﻼﻛ � يﺎﻬﻤﺘﻳرﻮﮕﻟا ﻪﻌﻄﻗ يﺎﻫﺰﻣر ونرﺎﻘﺘﻣ يﺎﻫﺰﻣر يا � يراﺬﮔﺰﻣر يﺎﻫدراﺪﻧﺎﺘﺳاﺎﻜﻳﺮﻣآ AES � ﻪﺘﻓﺮﺸﻴﭘ يراﺬﮔﺰﻣر دراﺪﻧﺎﺘﺳا � ﻪﻌﻄﻗ يﺎﻫﺰﻣر زا هدﺎﻔﺘﺳايا � ﻪﻌﻄﻗ يﺎﻫﺰﻣر يرﺎﻛ يﺎﻫﺪﻣيا � ﺖﻐﻟﻪﻣﺎﻧ DES � ﭘﺖﺳﻮﻴ 1: � ﭘﺖﺳﻮﻴ 2: 3DES,IDEA,Blowfish, RC5, CAST-128 ���� ���� ����� ���� 2 ���� ��� ﻒﻳرﺎﻌﺗ plaintext - the original message � ciphertext - the coded message � cipher - algorithm for transforming plaintext to ciphertext � key - info used in cipher known only to sender/receiver � encipher (encrypt) - converting plaintext to ciphertext � decipher (decrypt) - recovering ciphertext from plaintext � cryptography - study of encryption principles/methods � cryptanalysis (codebreaking) - the study of principles/ � methods of deciphering ciphertext without knowing key cryptology - the field of both cryptography and cryptanalysis � ���� ���� ����� ���� 3 ���� ��� 1

نرﺎﻘﺘﻣ يرﺎﮕﻧﺰﻣر (Symmetric) � ﻲﻟﻮﻤﻌﻣ ﺎﻳ / ﻲﺻﻮﺼﺧ ﺪﻴﻠﻛ / ﻚﺗيﺪﻴﻠﻛ � ﻲﻣ هدﺎﻔﺘﺳا كﺮﺘﺸﻣ ﺪﻴﻠﻛ ﻚﻳ زا هﺪﻧﺮﻴﮔ وهﺪﻨﺘﺳﺮﻓﺪﻨﻨﻛ � مﺎﻤﺗيﺎﻬﻳرﺎﮕﻧﺰﻣر نرﺎﻘﺘﻣ عﻮﻧ زا ﻚﻴﺳﻼﻛ ﺪﻨﺘﺴﻫ � ﻪﻫد زا ﻞﺒﻗ ﺎﺗ يرﺎﮕﻧﺰﻣر عﻮﻧ ﺎﻬﻨﺗ 70 ���� ���� ����� ���� 4 ���� ��� نرﺎﻘﺘﻣ يرﺎﮕﻧﺰﻣر لﺪﻣ ���� ���� ����� ���� 5 ���� ��� ﺎﻬﻳﺪﻨﻣزﺎﻴﻧ � نرﺎﻘﺘﻣ يرﺎﮕﻧﺰﻣر زا ﻦﻣا هدﺎﻔﺘﺳا ياﺮﺑ يﺪﻨﻣزﺎﻴﻧ ود : � يرﺎﮕﻧﺰﻣر ﻢﺘﻳرﻮﮕﻟا ﻚﻳيﻮﻗ � هﺎﮔآ نآ زا هﺪﻧﺮﻴﮔ وهﺪﻨﺘﺳﺮﻓ ﺎﻬﻨﺗ ﻪﻛ يﺮﺳ ﺪﻴﻠﻛ ﻚﻳﺪﻨﺘﺴﻫ Y = E K ( X ) X = D K ( Y ) � ﺖﺳا ﺺﺨﺸﻣ ﻪﻤﻫ ياﺮﺑ ﻢﺘﻳرﻮﮕﻟا ﻪﻛ ﺖﺳا نآ ﺮﺑ ضﺮﻓ . � ﺖﺳا ﺪﻴﻠﻛ ﻊﻳزﻮﺗ ياﺮﺑ ﻦﻣا لﺎﻧﺎﻛ ﻚﻳ ﻪﺑ زﺎﻴﻧ ﻦﻳاﺮﺑﺎﻨﺑ . ���� ���� ����� ���� 6 ���� ��� 2

يرﺎﮕﻧﺰﻣر � دﻮﺷ ﺺﺨﺸﻣ ﺮﻳز دﺎﻌﺑا ﻂﺳﻮﺗ ﺪﻧاﻮﺗ ﻲﻣ : � ﺰﻣر ياﺮﺑ هدﺎﻔﺘﺳا درﻮﻣ يﺎﻬﻠﻤﻋ عﻮﻧندﺮﻛ � ﻲﻨﻳﺰﮕﻳﺎﺟ / ﻞﻳﺪﺒﺗ / بﺮﺿ � درﻮﻣ يﺎﻫﺪﻴﻠﻛ داﺪﻌﺗهدﺎﻔﺘﺳا � ﻲﺻﻮﺼﺧ ﺎﻳ ﺪﻴﻠﻛ ﻚﻳ / ﺎﻳﺪﻴﻠﻛ ودﻲﻣﻮﻤﻋ � ﻦﺘﻣ شزادﺮﭘ شورﺢﺿاو � ﻲﻛﻮﻠﺑ / ﻲﻧﺎﻳﺮﺟ ���� ���� ����� ���� 7 ���� ��� يرﺎﮕﻧﺰﻣر ﻞﻴﻠﺤﺗ تﻼﻤﺣ عاﻮﻧا ciphertext only � only know algorithm / ciphertext, statistical, can � identify plaintext known plaintext � know/suspect plaintext & ciphertext to attack cipher � chosen plaintext � select plaintext and obtain ciphertext to attack cipher � chosen ciphertext � select ciphertext and obtain plaintext to attack cipher � chosen text � select either plaintext or ciphertext to en/decrypt to � attack cipher ���� ���� ����� ���� 8 ���� ��� تﻻﺎﺣ مﺎﻤﺗ يﻮﺠﺘﺴﺟ (Brute Force Search) � ﻦﻳﺮﺗ ﻲﻳاﺪﺘﺑاﻪﻠﻤﺣ � ﺖﺳا ﻲﻳﺎﺳﺎﻨﺷ ﻞﺑﺎﻗ ﺢﺿاو ﻦﺘﻣ ﻪﻛ ﺖﺳا ﻦﻳا ﺮﺑ ضﺮﻓ . ���� ���� ����� ���� 9 ���� ��� 3

ﻒﻳرﺎﻌﺗ ﺮﮕﻳد � ﺖﻴﻨﻣاﻖﻠﻄﻣ � عﻼﻃا هﺪﺷ ﺰﻣر ﻦﺘﻣ ،سﺮﺘﺳد رد ﻲﺗﺎﺒﺳﺎﺤﻣ ترﺪﻗ زا ﻞﻘﺘﺴﻣ ﺪﻨﻜﻧ ﻪﺋارا ﺢﺿاو ﻦﺘﻣ ﻲﻌﻄﻗ ﻦﻴﻴﻌﺗ ياﺮﺑ ﻲﻓﺎﻛ ) ﻦﻳاﺮﺑﺎﻨﺑ و دراد رﺎﻴﺘﺧا رد ﻦﻤﺷد ﻪﻛ ﻲﻧﺎﻣز تﺪﻣ زا ﻞﻘﺘﺴﻣ ﺰﻣر ﻢﺘﻳرﻮﮕﻟا ﺪﺷﺎﺒﻧ ﻦﺘﺴﻜﺷ ﻞﺑﺎﻗ ( � ﻲﺗﺎﺒﺳﺎﺤﻣ ﺖﻴﻨﻣا : � دوﺪﺤﻣ ﻲﺗﺎﺒﺳﺎﺤﻣ ﻊﺑﺎﻨﻣ ﻦﺘﺷاد ﺎﺑ ) نﺎﻣز ﺪﻨﻧﺎﻣ ( ﻞﺑﺎﻗ ﺰﻣر ، ﺪﺷﺎﺒﻧ ﻦﺘﺴﻜﺷ . ���� ���� ����� ���� 10 ���� ��� ﺐﻟﺎﻄﻣ ﺖﺳﺮﻬﻓ � ﻒﻳرﺎﻌﺗ � يﺎﻫﺰﻣر ﻚﻴﺳﻼﻛ � يﺎﻬﻤﺘﻳرﻮﮕﻟا ﻪﻌﻄﻗ يﺎﻫﺰﻣر ونرﺎﻘﺘﻣ يﺎﻫﺰﻣر يا � يراﺬﮔﺰﻣر يﺎﻫدراﺪﻧﺎﺘﺳا ﺎﻜﻳﺮﻣآ AES � ﻪﺘﻓﺮﺸﻴﭘ يراﺬﮔﺰﻣر دراﺪﻧﺎﺘﺳا � ﻪﻌﻄﻗ يﺎﻫﺰﻣر زا هدﺎﻔﺘﺳايا � ﻪﻌﻄﻗ يﺎﻫﺰﻣر يرﺎﻛ يﺎﻫﺪﻣ يا � ﺖﻐﻟ ﻪﻣﺎﻧ DES � ﭘﺖﺳﻮﻴ 1: � ﭘﺖﺳﻮﻴ 2: 3DES,IDEA,Blowfish, RC5, CAST-128 ���� ���� ����� ���� 11 ���� ��� يﺎﻫﺰﻣرﻚﻴﺳﻼﻛ • ﻲﻣراﺮﻗ هدﺎﻔﺘﺳا درﻮﻣ مود ﻲﻧﺎﻬﺟ ﮓﻨﺟ نﺎﻣز زاﺪﻨﺘﻓﺮﮔ • يزوﺮﻣا يﺮﺗﻮﻴﭙﻣﺎﻛ يﺎﻫ ﻢﺘﺴﻴﺳ نﺪﻣآ دﻮﺟو ﻪﺑ زا ﻞﺒﻗترﻮﺼﺑﺪﻧﺪﺷ ﻲﻣ مﺎﺠﻧا ﻲﺘﺳد . • ﻲﻠﺻا شور ود ﺮﺑ ﻲﻨﺘﺒﻣﻲﺘﺸﮕﻳﺎﺟ وﻲﻨﻳﺰﮕﻳﺎﺟ ﺖﺳا ���� ���� ����� ���� 12 ���� ��� 4

يﺎﻫﺰﻣرﻚﻴﺳﻼﻛ � ﻲﺘﺸﮕﻳﺎﺟ � ﻲﻨﻴﺸﻧﺎﺟ � ﻦﺘﻣ فوﺮﺣ ﻦﻴﺑ ﻲﻳﺎﺠﺑﺎﺟﻲﻠﺻا � فﺮﺣ ﺎﺑ فﺮﺣ ﻚﻳ ﻲﻨﻴﺸﻧﺎﺟﺮﮕﻳد diffusion � فﺪﻫ ) ﻲﮕﺘﺨﻳﺮﻤﻫرد ( � ﻚﺗﻲﻳﺎﺒﻔﻟا ﺮﺘﺸﻴﺑﺖﺳا � ﺪﻨﭼﻲﻳﺎﺒﻔﻟا � ﺖﺨﺳ ﺰﻣر ﺖﺴﻜﺷ ﻚﻳﺮﮔا ﺎﻣا ﺮﺗ � زاهدﺎﻔﺘﺳا ﺎﺑ هﺪﺷ ﻪﺘﺧﺎﻨﺷ تﻼﻤﺣ : pattern ) ﻮﮕﻟا ( ﻪﻤﻫ ،دﻮﺷ رﺎﻜﺷآ � ﺲﻧﺎﻛﺮﻓ ﻊﻳزﻮﺗ ﺎﻫ ﺖﺳا هﺪﺷ ﻪﺘﺴﻜﺷ ﻦﺘﻣ . � داﺪﻌﺗﺎﻫداﺪﺧر � تﺎﻤﻠﻛ لﺎﻤﺘﺣا وﻪﺑﺎﺸﻣ فوﺮﺣ pattern � ﻞﻴﻠﺤﺗ ) ﺎﻫﻮﮕﻟا ( ���� ���� ����� ���� 13 ���� ��� ﻲﻨﻴﺸﻧﺎﺟ ) راﺰﺳ (- ﻚﺗﺰﻣر ﻲﻳﺎﺒﻔﻟا send another catapult abcdefghijklmnopqrstuvwxyz abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz K = y r C = P + K (mod 26) rdmc zmnsqds bzszotks ﻚﺗ ﺰﻣرﻲﻳﺎﺒﻔﻟا • زاﺎﻬﻨﺗﻚﻳلﻮﻣﺮﻓ ﻲﻨﻳﺰﮕﻳﺎﺟ ﻲﻣ هدﺎﻔﺘﺳا قﻮﻓ لﻮﻣﺮﻓ ﻪﺑﺎﺸﻣ دﻮﺷ • ﺖﺳا نﺎﺳآ ﺎﻬﻧآ يرﺎﭙﺳ ﺮﻃﺎﺧ ﻪﺑ • هﺪﻫﺎﺸﻣ pattern ﺎﻫ نﺎﻜﻣا ﻲﻧﺎﺳآ ﻪﺑﺮﻳﺬﭘﺖﺳا ���� ���� ����� ���� 14 ���� ��� ﻲﻨﻴﺸﻧﺎﺟﻲﻳﺎﺒﻔﻟاﺪﻨﭼ ﺰﻣر ﻲﻳﺎﺒﻔﻟاﺪﻨﭼ • يﺎﻫ لﻮﻣﺮﻓ زا هدﺎﻔﺘﺳا ﻲﻨﻴﺸﻧﺎﺟ ﻒﻠﺘﺨﻣ ترﻮﺼﺑ ﻲﻟاﻮﺘﻣ pattern • ﺶﻫﺎﻛ ﻪﺑ ﺮﺠﻨﻣ ﻲﻣ ﺎﻫ دﻮﺷ • هدﺎﻔﺘﺳا ﺰﻣر ﺖﺴﻜﺷ ياﺮﺑ فوﺮﺣ ﻊﻳزﻮﺗ زا ناﻮﺗ ﻲﻣ نﺎﻨﭽﻤﻫ دﺮﻛ ���� ���� ����� ���� 15 ���� ��� 5