2.
Hash Function
Can be applied to a block of data of any size
●produce a fixed-length output
●relatively easy to compute of any given value,
making both hardware and software
implementations practical
●
3.
Hash Function
For any given hash code h, it is computationally
infeasible to find x such that H(x) = h. We called it
one-way property
●
4.
Hash Function
For any given block x, it is computationally
infeasible to find y <> x with H(y) = H(x). This is
referred to as weak collision resistance.
●
5.
Hash Function
It is computationally infeasible to find any pair (x,
y) such that H(x) = H(y). It is referred to as string
collision resistance.
●
6.
Usage
Password Protection
●As a fingerprint of a message, data or file
(Checksum)
●Data Normalization (ID Generation)
●
7.
Common Cracking
Pattern Finding
●Birthday Attack
●Dictionary Attack
●
8.
Solution
publish the method and open the source for all
people to review.
●increase the length of the hash code.
●add salt
●
9.
Possible Cracking of
HKID Hash Code
Server had been cracked
●Dictionary Attack
●man in middle (Depends on the Design)
●Virus
●Key Logger
●Binary or source code disclose
●
10.
Workshop
openssl
●md5sum
●shasum
●Fun on cracking my 30000 hash codes
●
Views
Actions
Embeds 0
Report content