Public key + private key

[dirtmcgirt]

If I have a BITCOIN public key + private key pair (wallet), this pair is good for litecoin too? (or for other crypto)

[bitcoin44me]

No, it will only work for btc.

[SeaBoundRhino]

If I have a BITCOIN public key + private key pair (wallet), this pair is good for litecoin too? (or for other crypto)

No this is not valid for Lite Coin. for litecoin you need to  download a  seperate Litecoin wallet and generate an new key pair.

[DeathAndTaxes]

Well not exactly.

You could use the same private key and public key for Litecoin (or any coin which uses ECDSA public keys and the same curve, which AFAIK is every clone coin to date).  However LiteCoin uses a different ADDRESS structure so you would need to compute the proper address for those keypairs.


Remember address =/= public key.  

There are three distinct elements:
Private key = random (or deterministic) 256 bit number.
Private key + ECDSA "magic" + particular ECC curve = public key.
Hashed public key with checksum, version information, and encoded into base 58 = public address.

[bitcoin44me]

Well not exactly.

You could use the same private key and public key for Litecoin (or any coin which uses ECDSA public keys and the same curve, which AFAIK is every clone coin to date).  However LiteCoin uses a different ADDRESS structure so you would need to compute the proper address for those keypairs.


Remember address =/= public key.  

There are three distinct elements:
Private key = random (or deterministic) 256 bit number.
Private key + ECDSA "magic" + particular ECC curve = public key.
Hashed public key with checksum, version information, and encoded into base 58 = public address.

It was obvious that he meant the address.

[pand70]

Although litecoin addresses are generated with the same way they have a different version number and so they start with an "L"

[DeathAndTaxes]

Or not but even if so the answer your provided is incomplete.  The same private key could be used for LiteCoin without issue.  Someone might want to do exactly that to simplify backups.  Have the exact same private keys in multiple wallets on different chains.  Another option would be to generate a paper wallet for both Bitcoin and LiteCoin using the same private key.   If you lost either one you could still recover funds by using the other one.

[jackjack]

Yes, you will have the same private key and a corresponding address for Litecoin (both the bitcoin and litecoin addresses will be "unlocked" by the private key)

See https://bitcointalk.org/index.php?topic=238776.0
For example, if you send 1BTC to 1oSYxNPiC7Mubb8Hexjg3qv7ZSCb37MLj and 1LTC to LL2PpAgDnrMRAQHHTnx2x4ugKmoUhP5odz, you are ABSOLUTELY SURE that the guy who controls one also controls the other one

[leowse]

I know that the address allows others to send you bitcoin, and the private key allows you to spend the bitcoin.
What does the public key do then?

[CIYAM]

What does the public key do then?

The public key is included in the script for spending UTXOs (inputs) so that anyone can verify that you do have the private key (an important reason why it is not a good idea to re-use addresses).

[Andyye]

What does the public key do then?

The public key is included in the script for spending UTXOs (inputs) so that anyone can verify that you do have the private key (an important reason why it is not a good idea to re-use addresses).

Sorry if this is a stupid question.

I have seen quite a lot of sites such as faucets and casinos keep reusing their hot wallet addresses.
So, will reusing address pose any real threat on the bitcoin in that address? How dangerous would it be?

[CIYAM]

So, will reusing address pose any real threat on the bitcoin in that address? How dangerous would it be?

The danger is that if the ECDSA that Bitcoin uses is somehow able to be broken (and so far it would appear not to have been) then it might turn out to be relatively easy for someone to determine your private key from your public key.

As an address is not your public key but is instead an irreversible hash of it then provided you never re-use an address the likelihood of being able to lose funds even if the ECDSA is broken would still be very, very low.

[dtsoiw]

I thought the answer is no, but I quickly find myself misunderstanding the keys and the address.
Just by reading the above posts (esp. the posts by DeathAndTaxes and CIYAM Open) help me learn a lot.

Thanks