I've heard ppl should use a new address every time they receive coin to help anonymity. Should you use a new address every time you send? Can you just use the same address for everything? Thanks!
there are 2 reasons people say change your bitcoin address.
1. it helps make it harder to tell who you are... since your bitcoin adresse you give out keeps changing.
2. it helps you keep track of were you bitcoins are coming from.
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There is also a security reason for using a new address for every transaction.
When you receive bitcoins at a brand new (never before used) address, the private key is protected from the bitcoin address by three algorithms: ECDSA, SHA-256, and RIPEMD-160.
As soon as you send bitcoins that were received at an address the public key becomes available in the blockchain, and the private key is only protected from the public key by ECDSA.
At the moment this is plenty of protection. There is currently no known feasible way to reverse ECDSA and figure out the private key from the public key. However, with a previously unused address a flaw would have to be discovered in all three algorithms nearly simultaneously, which is extremely unlikely and would allow time for bitcoin to implement a replacement function and time for you to move your coins to the new functionality. If you re-use addresses, then a flaw would only have to be discovered in the future in ECDSA for someone to potentially be able to access your bitcoins.