http://hg.viff.dk/viff/rev/395273e73571
changeset: 1078:395273e73571
user: Marcel Keller <[email protected]>
date: Mon Jan 12 19:22:37 2009 +0100
summary: Optimized byte_sub by initializing A only once.
diffstat:
1 file changed, 11 insertions(+), 10 deletions(-)
viff/aes.py | 21 +++++++++++----------
diffs (39 lines):
diff -r 3be465a9f016 -r 395273e73571 viff/aes.py
--- a/viff/aes.py Mon Jan 12 15:26:47 2009 +0100
+++ b/viff/aes.py Mon Jan 12 19:22:37 2009 +0100
@@ -67,6 +67,16 @@
self.rounds = max(self.n_k, self.n_b) + 6
self.runtime = runtime
+ # matrix for byte_sub
+ A = Matrix([[1,0,0,0,1,1,1,1],
+ [1,1,0,0,0,1,1,1],
+ [1,1,1,0,0,0,1,1],
+ [1,1,1,1,0,0,0,1],
+ [1,1,1,1,1,0,0,0],
+ [0,1,1,1,1,1,0,0],
+ [0,0,1,1,1,1,1,0],
+ [0,0,0,1,1,1,1,1]])
+
def byte_sub(self, state):
"""ByteSub operation of Rijndael.
@@ -107,17 +117,8 @@
bits = bit_decompose(inverted_byte)
- A = Matrix([[1,0,0,0,1,1,1,1],
- [1,1,0,0,0,1,1,1],
- [1,1,1,0,0,0,1,1],
- [1,1,1,1,0,0,0,1],
- [1,1,1,1,1,0,0,0],
- [0,1,1,1,1,1,0,0],
- [0,0,1,1,1,1,1,0],
- [0,0,0,1,1,1,1,1]])
-
# caution: order is lsb first
- vector = A * Matrix(zip(bits)) + Matrix(zip([1,1,0,0,0,1,1,0]))
+ vector = AES.A * Matrix(zip(bits)) +
Matrix(zip([1,1,0,0,0,1,1,0]))
bits = zip(*vector.rows)[0]
row[i] = reduce(lambda x,y: x + y,
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