information security
TRANSCRIPT
Information SecuritySINA BAGHERINEZHAD
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University of TehranFaculty of Management
Some Statistics
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Agenda
History
Definitions
Basic principles
Controls
Access Control
Cryptography
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History
ATBASH (600 BC)
Scytale (486 BC)
Caesar cipher (50 BC)
Alberti cipher (1466)
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Definitions of Information Security
Preservation of confidentiality, integrity and availability of information.
(ISO/IEC 27000:2009)
The protection of information and information systems from unauthorized
access, use, disclosure, disruption, modification, or destruction in order to
provide confidentiality, integrity, and availability. (CNSS, 2010)
Ensures that only authorized users (confidentiality) have access to
accurate and complete information (integrity) when required
(availability). (ISACA, 2008)
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Basic Principles
Confidentiality
Integrity
Availability
Authenticity
Non-repudiation
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Controls
Administrative
Logical
Physical
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Access Control
Identification
Authentication
Something you know: things such as a PIN, a password, or your mother's maiden
name.
Something you have: a driver's license or a magnetic swipe card.
Something you are: biometrics, including palm prints, fingerprints, voice prints
and retina (eye) scans.
Authorization (run, view, create, delete, or change)
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Cryptography
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Symmetric-key Cryptography
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Man-in-the-middle attack (MITM)
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Diffie-Hellman key exchange
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Public-key (Asymmetric) Cryptography
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RSA (cryptosystem)
Key generation:
1. Choose two distinct prime numbers p and q.
2. Compute n = pq.
3. Compute φ(n) = φ(p)φ(q) = (p − 1)(q − 1)
4. Choose an integer e such that 1 < e < φ(n) and gcd(e, φ(n)) = 1
5. Determine d as d.e ≡ 1 (mod φ(n))
Public key: (n, e)
Private key: (n, d)
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RSA (cryptosystem)
Encryption
1. Bob wishes to send message M to Alice.
2. He first turns M into an integer m, such that 0 ≤m < n
3. He then computes the ciphertext c corresponding to 𝐶 ≡ 𝑚𝑒 (mod n)
4. Bob then transmits c to Alice.
Decryption
1. Alice can recover m from c via computing 𝑚 ≡ 𝑐𝑑 (mod n)
2. Given m, she can recover the original message M.
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Digital signature
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References:
www.wikiperdia.com
www.scmagazine.com
www.comodo.com
www.billatnapier.com
www.noweco.com
www.ibm.com
www.iso.org
www.27000.org
نشر نص/ دکتر علی ذاکرالحسینی، دکتر احسان ملکیان /امنیت داده ها
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