t Wait a few blocks until you Txn=#871 George Anna 1 . can say - - PowerPoint PPT Presentation

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t Wait a few blocks until you Txn=#871 George Anna 1 . can say - - PowerPoint PPT Presentation

Jul 07, 2023 367 likes •584 views

RECAP View of someone who wants to make a transaction Block = # Prev = # B 1 B 2 ... B 8 B 9 B 10 B ... B Txn #871 t Wait a few blocks until you Txn=#871 George Anna 1 . can say that the transaction is

slide-1
SLIDE 1

RECAP

View of someone who wants to make a transaction

B1 B2 B8 B9 B10 Block = #… Prev = #… … Txn #871 … ...

Txn=#871 George Anna 1 ….

B’ B’’ ... Wait a few blocks until you can say that the transaction is confirmed

WHY WHY? Want some assurance that this block will be on the longest chain in the long run!

t

slide-2
SLIDE 2

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = B8 …. Txn #123 = … …. nonce SHA256 ( ) = 0x0b39d9ca51f07fef3429ae15…

slide-3
SLIDE 3

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = B8 …. Txn #123 = … …. nonce' SHA256 ( ) = 0x000000ef34244s1jd99a533g…

slide-4
SLIDE 4

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = B8 …. Txn #123 = … …. nonce’’ SHA256 ( ) = 0x1104000gf4jd8011889mdk3c…

slide-5
SLIDE 5

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = B8 …. Txn #123 = … …. nonce’’ SHA256 ( ) = 0x1104000gf4jd8011889mdk3c…

Txn=#871 George Anna 1 ….

I n c l u d e t h i s t r a n s a c t i

  • n
slide-6
SLIDE 6

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = B8 …. Txn #123 = … …. Txn #871 =… nonce’’’ SHA256 ( ) =

Txn=#871 Georgios Arvind 1 ….

I n c l u d e t h i s t r a n s a c t i

  • n

0x0000000aa38md69nb11efg48…

slide-7
SLIDE 7

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = B8 …. Txn #123 = … …. Txn #871 =… nonce’’ SHA256 ( ) = 0x0000000aa38md69nb11efg48… B9 You lost the race

9

slide-8
SLIDE 8

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = _å …. Txn #123 = … …. Txn #871 =… nonce’’ SHA256 ( ) = 0x0000000aa38md69nb11efg48… B9 You lost the race Remove transactions in B9 Update pointer to previous block

I

slide-9
SLIDE 9

PROOF OF WORK: RECAP

View of a miner

B1 B2 B8 ... Block = #8ae1… Prev = _å …. Txn #123 = … …. Txn #871 =… nonce SHA256 ( ) = 0x0000000aa38md69nb11efg48… B9 You lost the race Remove transactions in B9 Update pointer to previous block Keep trying!

slide-10
SLIDE 10

RECAP OF BITCOIN

  • Tr

Transactions: At any time, any buyer b can generate a transaction to pay d BTC to seller s.

  • Blo

Block: ck: A block consists of

  • A set of transactions
  • A cryptographic hash of the previous block (pointer

to previous block

  • An ID of the miner for this block
  • A nonce.
  • A set of properly signed transactions is va

valid if no account ever overspent its limit.

  • A block is valid if
  • It points to a valid block.
  • All transactions on the chain to B are valid.
  • SHA256(nonce|| info in block) has k leading zeros.
slide-11
SLIDE 11

RECAP OF BITCOIN II

  • Mi

Mini ning ng: : the process of extending the blockchain from some block B.

  • Longest Chain Protocol (for miners):
  • Choose B to be the block furthest from the root, tie-

breaking in favor of the first block you heard about.

  • Include all valid transactions you’ve heard about.
  • As soon as valid block created, announce it to the

network.

  • Miners are paid for creating valid blocks with

freshly minted Bitcoins and with transaction fees.

  • Difficulty of the puzzle is adjusted every 2016

blocks with the objective of making it so that a block takes 10 minutes to make in expectation.

slide-12
SLIDE 12

KEY IDEA

  • Trust the ledger that has the most

“computational work” put into it.

  • Ensure that fraudulent

transactions/conflicting ledgers would require an infeasible amount of computation to create.

slide-13
SLIDE 13

BITCOIN

  • Is a mechanism.
  • Question for us: are there beneficial

deviations that can help a miner earn more than his fair share of rewards?

slide-14
SLIDE 14

difficulty adjustment

longest

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slide-15
SLIDE 15

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slide-16
SLIDE 16

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slide-17
SLIDE 17

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slide-18
SLIDE 18

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slide-19
SLIDE 19

The Miners Dilemma

mining pools

used to reduce

the variance

pool

manager

that

joins

Bitcoin

as single mines

use partial proof of work

to figure

  • ut

how

to split rewards among

miners

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ima

slide-20
SLIDE 20

block rewards

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