Support multiproof in PINE

poc/flp_pine.py

@@ -10,7 +10,7 @@
 from common import Unsigned, Vec, front, gen_rand, next_power_of_2
 from field import Field, Field128
 from flp_generic import FlpGeneric, Mul, ParallelSum, Valid, test_flp_generic
-from xof import Xof, XofShake128
+from xof import Xof, XofFixedKeyAes128
 
 
 class PineValid(Valid):
@@ -38,7 +38,26 @@ class PineValid(Valid):
     # Associated types for `Valid`.
     Measurement = Vec[float]
     AggResult = Vec[float]
-    Field = Field128
+    Field = Field128  # Can be set by `with_field()`.
+
+    # Associated types for `PineValid`.
+    # Note we currently use `XofFixedKeyAes128` by default, because
+    # `XofTurboShake128` in VDAF poc has a limit of how many bytes can be
+    # sampled:
+    # https://github.com/cfrg/draft-irtf-cfrg-vdaf/blob/fd7a2dc4993babbf3acffc7d498cd7925890064b/poc/xof.py#L18-L21
+    Xof = XofFixedKeyAes128  # Can be set by `with_xof()`.
+
+    @classmethod
+    def with_xof(PineValid, TheXof):
+        class PineValidWithXof(PineValid):
+            Xof = TheXof
+        return PineValidWithXof
+
+    @classmethod
+    def with_field(PineValid, TheField):
+        class PineValidWithField(PineValid):
+            Field = TheField
+        return PineValidWithField
 
     def __init__(self,
                  l2_norm_bound: float,
@@ -528,7 +547,7 @@ def test():
     flp = FlpGeneric(pine_valid)
 
     # Test PINE FLP with verification.
-    xof = XofShake128(gen_rand(16), b"", b"")
+    xof = XofFixedKeyAes128(gen_rand(16), b"", b"")
     encoded_meas_no_wr = flp.encode(measurement)
     (wr_dot_prods, wr_res) = pine_valid.run_wr_checks(encoded_meas_no_wr, xof)
     flp_meas = encoded_meas_no_wr + wr_res + wr_dot_prods