ecdsa_sign(+Key, 
+Data, -Signature, +Options)hex) assumes that Data is an atom, 
string, character list or code list representing the data in hexadecimal 
notation. See rsa_sign/4 for an 
example.
Options:
- encoding(+Encoding)
 - Encoding to use for Data. Default is 
hex. Alternatives areoctet,utf8andtext.