Why do the biggest exchanges reuse Bitcoin addresses if doing so is unsafe?

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It's generally accepted that using one address for multiple transactions is unsafe, because sending a transaction reveals your public key (whereas only the hash of your public key is required to receive transactions).

If this is actually a safety concern, why do the biggest exchanges like Binance reuse their core storage addresses for many months, storing hundreds of millions of dollars? For example, Binance cold storage has 100 transactions: https://blockchain.info/address/16ftSEQ4ctQFDtVZiUBusQUjRrGhM3JYwe and Binance hot storage makes hundreds of transactions every day: https://blockchain.info/address/1NDyJtNTjmwk5xPNhjgAMu4HDHigtobu1s

As a side question, in theory everyone knows the public key of these addresses since they have outgoing transactions. Where is this information written? I can't find it on the transaction page of Blockchain.info: https://blockchain.info/tx/4d5b7175b4553d3239dae830837045adbe880b3d57dfc0c59a1bb8e6991b8ff8

rampatowl

Posted 2018-04-14T18:48:54.750

Reputation: 115

Answers

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It's generally accepted that using one address for multiple transactions is unsafe, because sending a transaction reveals your public key (whereas only the hash of your public key is required to receive transactions).

It's not unsafe. It is however gratuitously giving up privacy - yours, and that of others you interact with.

Pieter Wuille

Posted 2018-04-14T18:48:54.750

Reputation: 54 032