Does {Hidden strings} cipher effect work if its ciphered on to say {Niv-Mizzet, Dracogenius} and you use his ability to do one damage to target player will the ciphered spell resolve?
Niv would have to attack and deal combat damage in order to cipher the strings again.
Infinite is right, the answer is in the cipher wording. You only copy the coded card when combat damage is dealt not ability or effect damage.
What about a similar combo with {hellrider} and {hidden strings} cipher will the spell cast for each time a creature attacks {hellrider} deals one damage?
Combat damage, not ability damage
Cipher only triggers off combat damage.
Combat damage occurs when, in the combat damage phase, an attacking creature hits a defending player or blocking creature for damage equal to its power.
ALL other damage is considered non-combat damage. Even {Pit Fight} type fighting is non combat. Cipher will not trigger from this type of damage.