Methods and arrangements for effecting authentication in a secure transaction. There are defined, on behalf of a user, individuals who are members of a social network of the user. There is received, from the user, a transaction request for a secure transaction. An authentication test is conducted with the user and, upon meeting a predetermined requirement of the authentication test, the transaction request is validated. The authentication test requests the user to confirm at least one information item related to at least one member of the user's social network. Other variants and embodiments are broadly contemplated herein.