Economías criptográficas

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Economías criptográficas

  1. 1. Bitcoin Economy The raise of the crypto coins pnae@N21 ack Nk3
  2. 2. What is bitcoin? Peer to peer currency Powered by cryptography Profitability decreases in time Secure by computing power Value defined by market
  3. 3. Interesting for... Economy P2P networks Cryptography Hacking
  4. 4. What is 1 bitcoin? That's a bit difficult to explain...
  5. 5. In short ~0€ 10
  6. 6. In long...
  7. 7. Blockchain Records all transactions Groups transactions in blocks Cryptographically chained Stored by all clients Lightweight clients relay on server
  8. 8. The Genesis Block First block was hand-crafted 11Pe5Gf2MTT5LvDvN Az1PQeiDPfLSm7ifa Rewards 50 unspendable btc ht:/lcepoe.o tp/bokxlrrcm
  9. 9. Wallet The bitcoin address is the public key. Private key used to sign transactions Unlimited free addresses No tx concept... use address aliases vanitygen
  10. 10. Transactions Created by any client Signed with source address priv key Multiple destination addresses Need to be verified ~6 times Verification times depend on fee Cant be revoked User defined fee
  11. 11. Miners Enforce the blockchain creating blocks Group some random transactions (even invalid) Bruteforce a seed to get a small hash Difficulty depends on network power Reward for solved block (25btc + fee)
  12. 12. Pools Miners cant solve blocks fast enough to be profitable Join forces and reward shares Proof of work with lower difficulty PPS/PPLS/Prop/DGM/..
  13. 13. Hardware JS/JAVA (~1 MH/s) CPU (~6 MH/s) GPU (~60 MH/s) FPGA (less power consumption) ASIC (600 GH/s)
  14. 14. Other currencies Bitcoin is based on SHA256 and ECDSA Known as ALT coins Several forks appear Implement new core rules Most use SCRYPT to avoid ASICs
  15. 15. Litecoin Compared to silver Uses SCRYPT instead of SHA256 Faster verifications 2x more coins Difficulty redefined block ~$3
  16. 16. Namecoin DNS server Transfers to register domains Uses .bit 41.2 mBTC
  17. 17. Freicoin Demurrage Always profitable Promotes quick spends SHA256 0.2601 mBTC
  18. 18. Terracoin, Zerocoin, PPCoin, Novacoin, Zetacoin, ... ht:/w.onhoecm tp/wwcicos.o
  19. 19. Fix 51% attack (proof of stake) Less power consumption (ppcoin) More coins (feathercoin) Unlimited coins (Novacoin) Faster transactions (terracoin) Enhance anonymity (zerocoin) Mixed transactions (anoncoin)
  20. 20. Anonymity Every transaction is public Most trading sites require personal ID Many addresses can be tracked down from web/tw/fb/mail signatures. Not designed to be anonymous
  21. 21. Gateways There are payment gateways that sellers can use to accept bitcoins as payment and receive euro/dollar in change without any extra effort. or you may also want to trade..
  22. 22. Trading Many sites allow to trade between crypto-currencies, and also with real cash like euros or dollars. hts/bttm.e tp:/isapnt hts/vrue.o tp:/icrxcm hts/mgxcm tp:/to.o hts/bcecm tp:/t-.o
  23. 23. Security With enough power transaction validations can take forever. SeBQon. e BCi.
  24. 24. Alerts Broadcasted messages signed by Satoshi, Gavin, or Theymos. Notify about network problems or security vulnerabilities Put client in safe mode (isolate node)
  25. 25. Cracking Bruteforce private keys!
  26. 26. Well, there are ... ~^5 (ep5k)= 226 sc261 115,792, 089,237, 316,195, 423,570, 985,008, 687,907, 852,837, 564,279, 074,904, 382,605, 163,141, 518,161, 494,337 private keys...
  27. 27. Android to the rescue! openssl bug was reducing entropy source which caused predictable keys
  28. 28. Network Supports TOR Transactions are verified by all nodes DoS happened and got fixed quickly
  29. 29. Rainbows Impossible to cache all combinations prevhash (32 bytes) tx counter (1-9 bytes) timestamp (4 byte) seed (4 byte) N random transactions
  30. 30. Hacking Lite clients and bitcoin banks have been shown to be weak. Many btc banks or pools got hacked Sniffing weak client communications DoS manipulates the mining power SCAM (social engineering?) Trojans/Games/Webs with miners
  31. 31. Handjob BitcoinTools VanityGen BrainWallet JSON-RPC on bitcoind
  32. 32. Real use Trading Gambling Donations Buying stuff Laundry (ID required) Bypass VISA censorship
  33. 33. Future ATMs Credit Cards More clients More gateways Make it legal
  34. 34. EOF Any questions?

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