Add test vectors for the first 4 Pedersen hash generators.

Signed-off-by: Daira Hopwood <daira@jacaranda.org>

sapling_generators.py

@@ -3,6 +3,7 @@ from pyblake2 import blake2s
 
 from sapling_jubjub import Point, JUBJUB_COFACTOR
 from tv_output import render_args, render_tv
+from sapling_utils import i2leosp
 
 # First 64 bytes of the BLAKE2s input during group hash.
 # This is chosen to be some random string that we couldn't have
@@ -48,6 +49,9 @@ WINDOWED_PEDERSEN_RANDOMNESS_BASE = find_group_hash(b'Zcash_PH', b'r')
 VALUE_COMMITMENT_VALUE_BASE = find_group_hash(b'Zcash_cv', b'v')
 VALUE_COMMITMENT_RANDOMNESS_BASE = find_group_hash(b'Zcash_cv', b'r')
 
+required_bases = 4
+PEDERSEN_BASES = [find_group_hash(b'Zcash_PH', i2leosp(32, iminus1))
+                  for iminus1 in range(0, required_bases)]
 
 def main():
     render_tv(
@@ -60,6 +64,10 @@ def main():
             ('wprb', '[u8; 32]'),
             ('vcvb', '[u8; 32]'),
             ('vcrb', '[u8; 32]'),
+            ('pb0', '[u8; 32]'),
+            ('pb1', '[u8; 32]'),
+            ('pb2', '[u8; 32]'),
+            ('pb3', '[u8; 32]'),
         ),
         {
             'skb': bytes(SPENDING_KEY_BASE),
@@ -68,6 +76,10 @@ def main():
             'wprb': bytes(WINDOWED_PEDERSEN_RANDOMNESS_BASE),
             'vcvb': bytes(VALUE_COMMITMENT_VALUE_BASE),
             'vcrb': bytes(VALUE_COMMITMENT_RANDOMNESS_BASE),
+            'pb0': bytes(PEDERSEN_BASES[0]),
+            'pb1': bytes(PEDERSEN_BASES[1]),
+            'pb2': bytes(PEDERSEN_BASES[2]),
+            'pb3': bytes(PEDERSEN_BASES[3]),
         },
     )