Brief Information about SHA-3 Hash Function and Its relation to blockchain Systems and cryptocurrencies.

1. Presenter: S a dja d Ta l akoo b
Email: s a dja d_talako ob97@cmps2.iust. a c.ir
N e twork S e curity by D r A k ba ri
D e c e m b e r - 2 0 1 9
Let’s Talk About Hash

2. What We Offer
0001
Crypto Hash Function
0010
Brief History
0011
Blockchain
0100
cryptocurrency
0101
Security in BC
0110
Hash in BC
0111
One more thing
1000
Conclusion
B.
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3. Introduction
We Have Lots of Hash Fucntions - In compiler,web,Password,Spell checkers,Database,etc
We need only who related to Cryptography
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4. Cryptographic Hash Function Properties
Quick
Computation
Should return the hash
output quickly
Avalanche
Effect
Small change in the
input, change the whole
output.
Determinestic
Always get the same
result with same data
Pre-Image
Resistance
Infeasible to determine
input data based on the
output hash.
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5. Cryptographic Hash Function Properties
Collision Resistant
Each input has its own
unique hash.
Puzzle Friendly
Must be infeasible to find the
input from output and known
key
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6. The collision
resistance is
effectively broken
Output size is limited,
vulnerable to length
extension attacks
Arbitrary length output,Sponge
Construction
The Brief History
SHA1
SHA2
KECCAK / SHA3
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7. sPonge construction
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8. 7/20

9. The Blockchain
Blockchain simplifies complex transactions
• Replicated Ledger
• Consensus
• Cryptography
• Business Logic
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10. Consensus
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11. Cryptocurrency
• Cryptography has been a key technology in the financial
world for decades
• Bitcoin started in 2009
• Exploit advanced cryptographic techniques
• Today cryptography mostly secures point-to-point
interactions
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12. • Transparency
• Contract
Security and Privacy in Blockchain
• Transactional
• Accountability
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13. Hash in Blockchain
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14. Hash in Blockchain
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15. Hash in Blockchain
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16. One more thing
Merkle Tree
• Used in Cryptography and
computer science.
• Also called Hash tree.
• Every leaf node is labelled
with data block
• Every non-leaf node is
labelled with the
cryptographic hash of its
child node(s).
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17. Ethereum – hash function
• Using the same
underlying
algorithm that
used in SHA-3.
• KECCAK-256
hash function-
FIPS202.
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18. • Brief informations about Hash Fucntions.
• Why and How we use it in blockchain?
• Some new structures.
• Ehash from Ethereum
Conclusion
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19. • Hahsing Data Structures-Ananda Gunawardena-2015.
• Security Aspects of Blockchain -ITU Workshop -2017.
• Farfalle: parallel permutation-based cryptography-Guido Bertoni Et al.-2018.
• Xoodoo cookbook-Joan Daemen Et al.-2018.
• Xoodyak, a lightweight cryptographic scheme- Joan Daemen Et al.-2018.
Some of My Resources
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20. For The Attention
Thank You
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21. Any Question?
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Presenter: S a dja d Ta l akoo b
Email: s a dja d_talako ob97@cmps2.iust. a c.ir
N e twork S e c urity by D r A k ba ri
D e c e m b e r - 2 0 1 9

22. Backup Slides

23. FIPS202
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24. Which use which?
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25. Deep on Sponge
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26. Deep on Sponge
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27. Deep on Sponge
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