why Bitcoin use the elliptic curve secp265k1 in his crypthographie?

[raul750]

Hi

why Bitcoin use the elliptic curve secp265k1 in his crypthographie?

[pooya87]

why not use that curve?!
it is a 256 bit curve with a very good security that will remain safe for decades. it was supported by OpenSSL which Satoshi Nakamoto decided to use for bitcoin-QT (the  client he wrote as the first implementation of the protocol). because the size is 256 bit the signatures and consequently the transaction sizes aren't that big compared to if 384 or 521 bit were used. other curves like Curve25519 were around but weren't popular at the time.
it is a Koblitz curve so there are some characteristics that allows some performance boost which is good for a system like bitcoin.

[Bibite]

Isn't it the fastest curve and also the most secure against backdoors?