Security is a highly important thing in the cryptocurrency space. If a blockchain is not secure there could be possible vulnerabilities that allow malicious actors to mine more coins that there should be or even perform a double spend attack. A double spend attack is where a person is able to spend the same amount of currency twice, for example if a malicious actor had 2 Dash and was able to double spend it they could send the 2 Dash to two new addresses, effectively allowing them to own 4 Dash instead of 2...

Read more: https://www.dashnation.com/voices-of-dash-nation/how-dash-has-great-security/

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