/rev/444954db1fc9
changeset: 1328:444954db1fc9
user: Marcel Keller <[email protected]>
date: Fri Oct 23 14:59:34 2009 +0200
summary: aes: Masked exponentiation without preprocessing works again.
diffstat:
viff/aes.py | 12 +++++++-----
1 files changed, 7 insertions(+), 5 deletions(-)
diffs (30 lines):
diff -r 75fbb52aea09 -r 444954db1fc9 viff/aes.py
--- a/viff/aes.py Fri Oct 23 14:56:38 2009 +0200
+++ b/viff/aes.py Fri Oct 23 14:59:34 2009 +0200
@@ -155,19 +155,21 @@
return result
def invert_by_masked_exponentiation(self, byte):
- def add_and_multiply(masked_powers, random_powers):
- byte_powers = [Share(self.runtime, GF256, value) for value in
- map(operator.add, masked_powers, random_powers)[1:]]
+ def add_and_multiply(masked_powers, random_powers, prep):
+ byte_powers = map(operator.add, masked_powers, random_powers)[1:]
+ if prep:
+ byte_powers = [Share(self.runtime, GF256, value)
+ for value in byte_powers]
while len(byte_powers) > 1:
byte_powers.append(byte_powers.pop(0) * byte_powers.pop(0))
return byte_powers[0]
- random_powers = self.runtime.prss_powerchain()
+ random_powers, prep = self.runtime.prss_powerchain()
masked_byte = self.runtime.open(byte + random_powers[0])
masked_powers = self.runtime.schedule_callback(masked_byte,
lambda masked_byte: self.runtime.powerchain(masked_byte, 7))
return self.runtime.schedule_callback(
- masked_powers, add_and_multiply, random_powers)
+ masked_powers, add_and_multiply, random_powers, prep)
def invert_by_exponentiation(self, byte):
byte_2 = byte * byte
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