get Signature
Method to get params signature for an "HTTP"
request
Return
signature e.g. c8db66725ae71d6d79447319e617115f4a920f5agcdabcb2838bd6b712b053c4"
Parameters
signature Key
: key used to signature request
data
: data to sign
algorithm
: algorithm used in signature -> HmacSHA256 or HmacSHA512