A bitcoin private key is an elliptic curve private key on the secp256k1 curve. OpenSSL will let you encode a valid bitcoin private key as a PEM if you wish for

A bitcoin private key is an elliptic curve private key on the secp256k1 curve. OpenSSL will let you encode a valid bitcoin private key as a PEM if you wish for easy copy paste -- you would have to convert them into another format for direct usage however. eg: openssl genpkey -algorithm EC -outform PEM -pkeyopt ec_paramgen_curve:secp256k1 -pkeyopt ec_param_enc:named_curve There is a native format known as WIF (wallet import format) that uses ascii encoding for private keys, allowing easy migration/copy paste: https://en.bitcoin.it/wiki/Wallet_import_format https://en.bitcoin.it/wiki/Wallet_import_format