I'm having a problem that I can't solve since yesterday with the blockCypher APIs when I try to create a new transaction for bitcoin and submit it.
https://www.blockcypher.com/dev/bitcoin/?shell#creating-transactions
i have to sign locally but their php or cURL code don't work (they give me several problems)
I searched the internet but found nothing suitable.
this is what the API say
# next, you sign the data returned in the tosign array locally
# any ECDSA secp256k1 signing tool should work
# $PRIVATEKEY here is a hex-encoded private key corresponding to the input from address
CEztKBAYNoUEEaPYbkyFeXC5v8Jz9RoZH9
sign: 32b5ea64c253b6b466366647458cfd60de9cd29d7dc542293aa0b8b7300cd827 $PRIVATEKEY
3045022100921fc36b911094280f07d8504a80fbab9b823a25f102e2bc69b14bcd369dfc7902200d07067d47f040e724b556e5bc3061af132d5a47bd96e901429d53c41e0f8cca
do you have any algorithm that i can use in php?