Well, I don't know if the technology from the XB-70 is being used in the Aurora, but from my knowledge of the sightings, the two planes are
completely different. Many observers have reported the Aurora is essentially a black triangle, with 2 distinctive, "bulbus" air intake vents on the
sides. Anything resembling the XB-70 would much easier to recognise, as its features are more visible, the Concorde Nose, the air intakes on the
fuselage, the stabilising fins, and the flat triangular rear exhaust.
All I'm saying is that I highly doubt the XB-70 has now been converted into the Aurora aircraft, while they may have borrowed technology, I doubt the
XB-70 design is still used.
Compare these photos/graphics of the Aurora and XB-70:
Alleged Aurora Sighting:
Common Aurora Concept Drawing:
Now compare the Valkyrie:
Similar yet different...