1. Alexander Bernauer alex@copton.net

2. What is Bitcoin?

3. Bitcoin Client

4. Motivation

5. What is a Currency? ● unforgeable ● exchangable ● quantifiable ● storable TRUS T

6. How can I obtain Bitcoins?

7. What can I spend Bitcoins on?

8. The Distributed Database Block n Block n + 1 Transaction

9. Controlled Currency Supply ● 6 blocks per hour ● 50 BTC per block award ● 50% award reduction per 4 years ● max. 21e6 BTC in 136 years

11. Bitcoin Address 123456789 ABCDEFGHJKLMNPQRSTUVWX YZ abcdefghijkmnopqrstuvwxyz version [1]: 0x00 (main) | 0x6f (test) | 0x34 (namecoin) key_hash [21]: version + ripemd_160(sha_256(public_key)) point on elliptic curve (ECDSA) x [32]:... y [32]:... public_key [65]: 0x04 + x + y checksum [4]: head(sha_256(sha_256(key_hash))) address [25-34]: base58(key_hash + checksum)

12. Block

13. Merkle Tree

14. Target ● Keep 10 minutes per block on average ● Re-target every 2016 blocks ● Change is always less than factor 4 Maximum Target: 0x00000000 ffff0000 00000000 Packed representation: a [3]: significant b [1]: exponent target [32]: a * 2^(8*(b-3)) bits [4]: b + a Maximum Target (packed): 0x1d00ffff

15. Difficulty Definition: difficulty := maximum_target / current_target

16. Transaction

17. Block n+1 Block n The Distributed Database Revised

18. Output Point

19. Input Point

20. Bitcoin Script Transfer to Bitcoin address: sig_script: pk_script:OP_DUP OP_HASH160 OP_EQUALVERIFY OP_CHECKSIG Transfer to IP address: sig_script: pk_script: OP_CHECKSIG Authorization: exec(sig_script + pk_script) = True

21. Signatures SIGHASH_ALL

22. Signatures SIGHASH_NONE my input foreign input

23. Signatures SIGHASH_SINGLE my in point out point with same index foreign input

24. Signatures SIGHASH_ALL + ANYONECANPAY my input foreign input

25. Contracts Escrow: sig_script: pk_script:2 3 OP_CHECKMULTISIG ● Providing a deposit ● Assurance contracts ● Digital heritage

26. Fees and Generated Coins Transaction fee: sum(output values) - sum(input values) Miner award: mined_coins + sum(fees) Block body: generation transaction transaction 2... transaction n

27. Generation Transaction Generation Input Point Transfer to IP address Transfer to Bitcoin address......

28. Generation Input Point

29. Numbers ● Number of Bitcoins ● http://blockexplorer.com/q/totalbc ● Size of the block chain ● http://blockexplorer.com/q/getblockcount ● http://blockexplorer.com/q/avgblocksize ● Odds ● http://blockexplorer.com/q/hextarget ● http://blockexplorer.com/q/probability ● Total power consumption ● http://bitcoinwatch.com ● https://en.bitcoin.it/wiki/Mining_hardware_comp arison

30. 

31. Properties 0xdeadbeef

32. Problems

35. Links ● https://en.bitcoin.it ● http://bitcoincharts.net ● https://mtgox.com ● http://eligius.st ● http://www.bitcoinclassifieds.net ● http://dot-bit.org ● http://bitcoinexplorer.com ● http://bitcoinwatch.com

36. Sources http://en.bitcoin.it/wiki/ http://upload.wikimedia.org/wikipedia/commons/6/6d/Hash_tree.png http://upload.wikimedia.org/wikipedia/commons/c/cd/ASF-logo.svg http://upload.wikimedia.org/wikipedia/commons/0/0c/MIT_logo.svg http://upload.wikimedia.org/wikipedia/en/b/b8/Bitcoin-0.3.23-ubuntu.png http://upload.wikimedia.org/wikipedia/commons/7/7b/United_States_one_dollar_ bill%2C_obverse.jpg http://upload.wikimedia.org/wikipedia/commons/d/de/Road-sign-works.svg http://upload.wikimedia.org/wikipedia/commons/1/1a/EFF_Logo.svg http://upload.wikimedia.org/wikipedia/commons/6/66/Kokain_-_Cocaine.svg http://upload.wikimedia.org/wikipedia/commons/4/4a/Kamasutra5.jpg http://upload.wikimedia.org/wikipedia/commons/c/c5/Bitcoin_logo.svg http://upload.wikimedia.org/wikipedia/commons/5/50/Bitcoin.png http://www.gettyicons.com/free-icon/112/must-have-icon-set/free-zoom-in-icon- png/ http://www.gettyicons.com/free-icon/145/where-are-my-money-icon-set/free- bank-icon-png/ http://www.gettyicons.com/free-icon/103/pretty-office-5-icon-set/free-go-back- icon-png/ http://www.gettyicons.com/free-icon/142/network-icon-set/free-global-network- icon-png/ http://www.gettyicons.com/free-icon/133/shimmer-icon-set/free-world-icon-png/ http://www.lovecoffeeandtea.com/wp-content/uploads/2011/07/Fair-Trade- Coffee.jpg http://www.flickr.com/photos/chipgriffin/2210297177/ http://www.flickr.com/photos/stefan-fehrmann/2593677182/ http://www.flickr.com/photos/andreelau/5086996376/ http://www.flickr.com/photos/franziska/105215812/ http://www.flickr.com/photos/lapideo/198046070/ http://www.flickr.com/photos/purzlbaum/131322462/ http://www.flickr.com/photos/fornal/405213497/ http://www.flickr.com/photos/mcschindler/5081539636/ http://www.bijusubhash.com/blog/golden-hour-glass-icon http://pentabarf.org http://knowyourmeme.com/memes/futurama-fry-not-sure-if-x http://memegenerator.net