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بنام خدا پروتكلهاي احراز اصالت

Authentication protocols

فهرست مطالب
مقدمه
احرازاصالت ضعيف( كلمات عبور)
احرازاصالت قوي (مبتني بر سؤال و جواب)
پروتکل کربروس مقدمه مقدمه Something you know (a PIN, or password).
Something you have:
secureID card or other token, generating a one-time password.
a key imbedded in a ‘secure area’
a smartcard (which may have keys imbedded and can perform cryptographic operations on behalf of a user).
Something you are (a biometric).

Basis for Authentication فهرست مطالب
مقدمه
احرازاصالت ضعيف( كلمات عبور)
احرازاصالت قوي (مبتني بر سؤال و جواب)
پروتکل کربروس احراز اصالت ضعيف احراز اصالت ضعيف احراز اصالت ضعيف Password Vulnerabilities Writing them down

Stolen passwords (via eavesdropping)
Trojan Horse
Poor password choice
Easy to guess, easy to remember
People use the same password multiple times
Passwords changed infrequently
Offline attacks
Search through password dictionary Survey of 3,289 Passwords With no constraints on choice of password
15 were a single ASCII letter.
72 were strings of two ASCII letters.
464 were strings of three ASCII letters.
47 were strings of four alphanumerics.
706 were five letters, all upper-case or all lower-case.
605 were six letters, all lower case. حملات عليه روشه هاي مبتني بر کلمه عبور و راه کار مقابله حملات عليه روشه هاي مبتني بر کلمه عبور و راه کار مقابله بهبود امنيت در روش هاي مبتني بر کلمه عبور قوانين کلمه عبور کاهش سرعت نگاش نمک زدن عبارتهاي کلمه عبور احراز اصالت دو عاملي احراز اصالت دو عاملي کلمه عبورهاي يک بار مصرف کلمه عبورهاي يک بار مصرف کلمه عبورهاي يک بار مصرف کلمه عبورهاي يک بار مصرف کلمه عبورهاي يک بار مصرف فهرست مطالب
مقدمه
احرازاصالت ضعيف( كلمات عبور)
احرازاصالت قوي (مبتني بر سؤال و جواب)
پروتکل کربروس In strong authentication, one entity ‘proves’ its identity to another by demonstrating knowledge of a secret known to be associated with that entity, without revealing that secret itself during the protocol.
Also called `challenge-response’ authentication.
Use cryptographic mechanisms to protect messages in protocol:
Encryption.
Integrity mechanism (e.g. MAC).
Digital signature. Strong Authentication A B: ‘Hi Bob, I’m Alice’
B A: R (challenge)
A B: {R || B}K (response)

(Here, {X}K means string X encrypted under key K, a...