In a blog post, Wednesday Coinbase said that more than 99% of customer assets are held in offline cold storage, and that last week’s $6.34 billion hack at rival Binance did not affect its sys
In a blog post, Wednesday Coinbase said that more than 99% of customer assets are held in offline cold storage, and that last week’s $6.34 billion hack at rival Binance did not affect its systems or customer funds.
The U.S. exchange set out its security controls in the post.
It said the Oct. 29 theft, which the FBI has attributed to North Korea’s TraderTraitor group, had left customers asking how it guards against a similar attack.
Related: Binance founder issues chilling warning after record crypto heist
Cold wallets are not connected to the internet. Coinbase moves funds into internet-connected hot wallets only as customers need them for withdrawals.
Private keys for the cold wallets are split into pieces and never fully reassembled, even when transactions are signed. No single employee has standing access to the hot-wallet signing service.
Strict limits cap how fast money can move from cold to hot storage, and unusual withdrawal spikes are held for staff review. The exchange can also trigger kill switches that take signing keys offline entirely.
Coinbase said it assumes employees will be targeted by phishing, so sensitive actions need multiple approvals. A stolen password, session or device cannot be used on its own.
In the post, Coinbase said customer assets are held 1:1 and are not lent out unless customers direct it. It reported $377 billion in assets on its platform and $8.6 billion in cash and cash equivalents as of Sept. 30.
The company has had its own security problems. In May 2025, it disclosed that criminals had bribed overseas customer support agents to steal personal data on less than 1% of its monthly transacting users.
The attackers then demanded a $20 million ransom, which Coinbase refused to pay.
Binance, for its part, has set aside $6.34 billion of its own money to cover losses from its hack.
Coinbase flagged artificial intelligence as a fast-changing security threat and pledged further investment.
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