code: func (a *AccountService) NewEAB(accMsg acme.Account, kid string, hmacEncoded string) (acme.ExtendedAccount, error) {
  	hmac, err := base64.RawURLEncoding.DecodeString(hmacEncoded)
  	if err != nil {
  		return acme.ExtendedAccount{}, fmt.Errorf("acme: could not decode hmac key: %v", err)
  	}
  
  	eabJWS, err := a.core.signEABContent(a.core.GetDirectory().NewAccountURL, kid, hmac)
  	if err != nil {
  		return acme.ExtendedAccount{}, fmt.Errorf("acme: error signing eab content: %v", err)
  	}
  	accMsg.ExternalAccountBinding = eabJWS
  
  	return a.New(accMsg)
  }
docs: // NewEAB Creates a new account with an External Account Binding.