class OpenSSL::PKey::EC

def ssh_do_sign(data, sig_alg = nil)

Returns the signature for the given data. 
def ssh_do_sign(data, sig_alg = nil)
  digest = digester.digest(data)
  sig = dsa_sign_asn1(digest)
  a1sig = OpenSSL::ASN1.decode(sig)
  sig_r = a1sig.value[0].value
  sig_s = a1sig.value[1].value
  Net::SSH::Buffer.from(:bignum, sig_r, :bignum, sig_s).to_s
end