From bb0c161e7d4bff0e70b59c2f4267da96f34742af Mon Sep 17 00:00:00 2001 From: Riccardo Spagni Date: Mon, 24 Aug 2015 19:34:10 +0200 Subject: renamed folder --- .../ref10CommentedCombined/sqrtm1.py | 28 ++++++++++++++++++++++ 1 file changed, 28 insertions(+) create mode 100644 src/crypto/crypto_ops_builder/ref10CommentedCombined/sqrtm1.py (limited to 'src/crypto/crypto_ops_builder/ref10CommentedCombined/sqrtm1.py') diff --git a/src/crypto/crypto_ops_builder/ref10CommentedCombined/sqrtm1.py b/src/crypto/crypto_ops_builder/ref10CommentedCombined/sqrtm1.py new file mode 100644 index 000000000..9a47fbc12 --- /dev/null +++ b/src/crypto/crypto_ops_builder/ref10CommentedCombined/sqrtm1.py @@ -0,0 +1,28 @@ +q = 2**255 - 19 + +def expmod(b,e,m): + if e == 0: return 1 + t = expmod(b,e/2,m)**2 % m + if e & 1: t = (t*b) % m + return t + +def inv(x): + return expmod(x,q-2,q) + +def radix255(x): + x = x % q + if x + x > q: x -= q + x = [x,0,0,0,0,0,0,0,0,0] + bits = [26,25,26,25,26,25,26,25,26,25] + for i in range(9): + carry = (x[i] + 2**(bits[i]-1)) / 2**bits[i] + x[i] -= carry * 2**bits[i] + x[i + 1] += carry + result = "" + for i in range(9): + result = result+str(x[i])+"," + result = result+str(x[9]) + return result + +I = expmod(2,(q-1)/4,q) +print radix255(I) -- cgit v1.2.3