P. 10



               Security breach and invalid addresses (2011)
               McCaleb sold the site to French developer Mark Karpelès, who was living in Japan, in March 2011, saying
               "to really make mtgox what it has the potential to be would require more time than I have right now. So
               I’ve decided to pass the torch to someone better able to take the site to the next leve

               On 19 June 2011, a security  breach of the Mt. Gox bitcoin  exchange  caused the nominal  price of
               a bitcoin  to fraudulently  drop to one cent on the Mt. Gox exchange,  after a hacker allegedly  used
               credentials  from  a Mt. Gox auditor's  compromised  computer  to transfer  a large  number  of
               bitcoins  illegally  to himself.  He used the exchange's  software  to sell  them  all  nominally,  creating
               a massive  "ask"  order at any  price. Within  minutes  the price corrected to its correct user-traded
               value. [24][25][26][27][28][29]  Accounts with  the equivalent  of more than $8,750,000 were affected. [26]
               In order to prove that Mt. Gox still  had control  of the coins, the move  of 424,242 bitcoins  from
               "cold  storage"  to a Mt. Gox address was announced  beforehand,  and executed  in  Block
               132749. [30]

               n October 2011, about two dozen transactions  appeared in the block chain  (Block 150951) [31]
               that sent a total of 2,609 BTC to invalid  addresses. As no private  key could  ever be assigned  to
               them,  these bitcoins  were effectively  lost. While  the standard client  would  check for such an
               error and reject the transactions,  nodes on the network would  not, exposing  a weakness in the

               Processor of most of world's bitcoin trades; issues (2013)

               On 22 February 2013, following  the introduction  of new anti-money  laundering  requirements  by
               e-commerce/online  payment  system  company  Dwolla,  some Dwolla  accounts  became
               temporarily  restricted.  As a result,  transactions  from  Mt. Gox to those accounts  were cancelled
               by Dwolla.  The funds  never made it back to Mt. Gox accounts.  The Mt. Gox help desk issued  the
               following  comment:  "Please  be advised  that you are actually  not allowed  to cancel any
               withdrawals  received  from  Mt. Gox as we have never  had this  case before and we are working
               with  Dwolla  to locate your  returned  funds."  The funds  were finally  returned  on May 3, nearly
               three months  later,  with  a note:  "Please  be advised  never to cancel any  Dwolla  withdrawals  from
               us again".

               In March 2013, the bitcoin  transaction  log  or "blockchain"  temporarily  forked into  two
               independent  logs,  with  differing  rules  on how transactions  could be accepted. The Mt. Gox
               bitcoin  exchange  briefly  halted  bitcoin  deposits.  Bitcoin  prices briefly  dipped by 23%, to $37, as
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