The Wonder of Merkle Trees

I think that every child at school should read the Satoshi Nakamoto paper. In the paper, Satoshi lays out a more trusted world, and at its core is the usage of Merkle Trees. With this we create a tree of hashes and then it this to create a root hash. In blockchain, it is this root hash that we add to our blockchain, in order to create a chaining effect.

So let’s say we have the names of a few countries: ‘France’, ‘Germany’, ‘Denmark’, ‘Sweden’, ‘UK’, ‘Spain’, and ‘Italy’. We can then hash as [here]:

Input:		 [ 'France', 'Germany', 'Denmark', 'Sweden', 'UK', 'Spain', 'Italy' ]
Root hash:	 65C7C87E2731AE97D0BE89EA3299A544FD28DE6A
Tree depth	 3
Tree levels:	 4
Tree nodes:	 7

Level  0
[ '65C7C87E2731AE97D0BE89EA3299A544FD28DE6A' ]

Level  1
[ '8D832398ACABF7B669C023174169C8876F9764DC',
  '2BBB8E1E1D16671B763D0C026C9A2BA43FD73381' ]

Level  2
[ '0F705D70B6CF6FFE1FE570FC24947767438541FA',
  'A5D0D57347C4BE03B6E91E0176D5E53614AA861E',
  'F8A5C1FC111019BDCD2E6F7877299878F9699640',
  'AD79EF0F076D3A686AB9738925F4DD2C7E69D7D1' ]

Level  3
[ 'E3772AC4B4DB87B4A8DBFA59EF43CD1A8AD29515',
  '17D53E0E6A68ACDF80B78D4F9D868C8736DB2CEC',
  '89DA124E04DFE1AD9946CD37D91A119E1D028898',
  '72DDD2B619AF6D6A73FEBF80F7FCAD22495498CD',
  '7770D04C7BFB791E7C95959F12D6797BEE87A8D8',
  '20A8DF9B760336178FCA425339EC1C7E542A2463',
  'AD79EF0F076D3A686AB9738925F4DD2C7E69D7D1' ]