SERDANG: Following the recent ''WannaCry'' ransomware cyber attack, which blackmailed computer users worldwide, those dealing in digital currencies such as Bitcoin need to be more vigilant and keep their accounts secure.

Network security expert Assoc Prof Dr Zuriati Ahmad Zukarnain said although Bitcoin operates using two key types - public and private - to make transactions, the private key could be hacked by third parties using highly capable quantum computers.

"Quantum computers are able to create a 'large factorisation' and can detect the public and private keys used in Bitcoin transactions.

"The threat is when the 'private key' is sniffed by third parties, they are free to make transactions using a hacked account as the 'private key' proves the ownership of a Bitcoin address (used to send and receive the currency)," she told Bernama.

Last month, the "WannaCry" ransomware affected hundreds of thousands of users worldwide, locking access to the files on their computer, and then requesting Bitcoin payments to unlock them.

Zuriati said the Bitcoin's private key was used to keep safe the Blockchain, a public digital database which keeps records on all bitcoin transactions.

Zuriati, a lecturer at Universiti Putra Malaysia's Communication Technology and Networking department, said if the third party managed to hack the private key, they could have access to the value of Bitcoin in a hacked account.

She said studies showed that the use of digital currency had become popular in Malaysia as payment transactions were more convenient than using credit cards, besides being secure, fast and cheap.

In an effort to enhance the safety of Bitcoin, Zuriati said the Russian Quantum Centre had suggested that each account's blockchain is coupled with Quantum Key Distribution (QKD) and ''post-quantum cryptography''.

In this way, she said the ''peer-network'' architecture used in Bitcoin system would be more secure, thus preventing the private key from being stolen by third parties.

The Bitcoin currency was created by a computer expert using the pseudonym Satoshi Nakamoto, and it operates independently of any central bank, allowing transfers by electronic means without middlemen for free.

While the value of currency is typically backed with gold or silver, Bitcoin is backed with mathematical calculations.

The currency has become popular because central banks of countries cannot control a person's financial affairs, and it has become one of the preferred mode of transactions for small businesses.