Galvanic corrosion typically happens at 0.5V (and as low as 0.15V in salt-water); 1.7V is "ultra high potential" in comparison with normal corrosion thresholds.

The potential needed for electrolysis of water is 1.23V in theory, in practice a bit more to overcome inefficiencies. 1.7V is enough.

I think that may not be the potential used for electrolysis, but the chemical potential of the saltwater-metal boundary. But hopefully someone more knowledgeable will comment.