Despite the high level of security, decentralized marketplaces have their vulnerabilities, like double-spending:
a hacker attack a platform in order to spend the online multi store shopping mall coins twice.
It is possible through a 51% attack
: in order to achieve a majority on the blockchain computers' network, a hacker would need to control at least 51% of them.
Such an attack is extremely difficult to execute for a blockchain of a big scale, but if users numbered in the dozens, it would be easier
Thus, newer blockchain marketplaces are more susceptible to 51% attacks. The throughput of some blockchains are quite low
, that decreases the number of transactions that can be created during a certain time period and doesn't allow to scale a online multi-seller mall.
Another point is that the large portion of the user's data is confidential, thus some sorts of promotion are impossible to use
— like product recommendations, bundling and personalization algorithms as well as target future promotions.
There are the technical implementation problems as well
, connected to the applications and wallets that are built on top of the blockchain ledger. Refunds
can potentially become one of the main issues of decentralized marketplaces due to the fact that the transactions written in a block are irreversible.
Also, PricewaterhouseCoopers survey
highlights the lack of trust among users as one of the main barriers to blockchain adoption: