The third week of January has been exciting for the cryptocurrency markets. Perhaps the biggest news is that the Cryptopia exchange suffered a major hack. On Tuesday the young New Zealand-based exchange announced on Twitter that it experienced a significant security breach. Third party analysts reported that hackers possibly had transferred 19,391 Ethereum (ETH) and 48 million Centrality (CENNZ) tokens worth over $3.6 million offsite from Cryptopia. Cryptopia revealed that it is cooperating with the New Zealand police and a special cybercrimes unit to help solve the case. All trading on the exchange was suspended after the breach was publicized.

Here is the rest of the week in review:

The Ethereum hard fork Constantinople, scheduled for this week, was delayed again on Friday. The Ethereum developers made the decision to delay after they recently discovered a security vulnerability in the Constantinople code. The vulnerability allowed a bad actor to input false data into a smart contract and repeatedly request funds in order to steal the ETH balance. The developers delayed the hard fork to block 7,280,000, estimated to be on February 27. The Constantinople hard fork will incorporate several improvement proposals and spark the transition from a proof-of-work consensus algorithm to a hybrid system with proof-of-stake. Originally slated to occur last year, the hard fork has been called the least eventful one ever by Ethereum developers.

Coinstar announced it will allow customers to buy Bitcoin (BTC) on its store kiosks. The firm operates kiosks that convert physical coins to cash and Amazon (AMZN  ) gift cards at thousands of grocery stores in the US. Coinstar chief executive Jim Gaherity stated that Coinstar's usable kiosks will allow people to easily buy BTC with cash. The kiosks will accept only US dollar bills, up to $2,500. Users will need to give their phone number and register for an online account in order to redeem purchased BTC. The Bitcoin kiosks will debut in California, Texas, and Washington and expand to more states if there is customer demand.

Crypto prices slumped and then rebounded this week to end at $120 billion. BTC was just under $3,600 in low volume trading. In the top 100, the biggest losers are Vitae (VITAE), down 32 percent, Timicoin (TMC), down 27 percent, and Peercoin (PPC), down 14 percent. The biggest gainers are Apollo Currency (APL), up 288 percent, StarCoin (KST), up 112 percent, and Steem (STEEM), up 61 percent. Traders will likely watch the if the majors can break out above the 10 and 21-day exponential moving averages.

The author owns a small amount of BTC.