Why did Satoshi decide to use secp256k1 instead of secp256r1?
Secp256k1 and secp256r1 are two commonly used curves. Hyperledger / Fabric developed by IBM is using secp256r1 while Bitcoin is using secp256k1. What is the difference between these two and why did Satoshi decide to use secp256k1 which is considered as a surprising choice at the time?