diff options
| -rw-r--r-- | src/math/numbertheory/powm_fw.cpp | 35 | ||||
| -rw-r--r-- | src/pubkey/elgamal/elg_op.cpp | 6 | ||||
| -rw-r--r-- | src/pubkey/nr/nr_op.cpp | 8 |
3 files changed, 39 insertions, 10 deletions
diff --git a/src/math/numbertheory/powm_fw.cpp b/src/math/numbertheory/powm_fw.cpp index b764ee7aa..e4272f20d 100644 --- a/src/math/numbertheory/powm_fw.cpp +++ b/src/math/numbertheory/powm_fw.cpp @@ -77,17 +77,40 @@ BigInt Fixed_Window_Exponentiator::execute() const { const u32bit exp_nibbles = (exp.bits() + window_bits - 1) / window_bits; - BigInt x = 1; - for(u32bit j = exp_nibbles; j > 0; --j) + if(exp_nibbles == 0) + return 1; + + BigInt x1 = 1; + + for(u32bit j = 0; j != exp_nibbles / 2; ++j) + { + for(u32bit k = 0; k != window_bits; ++k) + x1 = reducer.square(x1); + + u32bit nibble = exp.get_substring(window_bits*(exp_nibbles-1-j), + window_bits); + + if(nibble) + x1 = reducer.multiply(x1, g[nibble-1]); + } + + for(u32bit k = 0; k != window_bits; ++k) + x1 = reducer.square(x1); + BigInt x2 = 1; + + for(u32bit j = exp_nibbles / 2; j != exp_nibbles; ++j) { for(u32bit k = 0; k != window_bits; ++k) - x = reducer.square(x); + x2 = reducer.square(x2); + + u32bit nibble = exp.get_substring(window_bits*(exp_nibbles-1-j), + window_bits); - u32bit nibble = exp.get_substring(window_bits*(j-1), window_bits); if(nibble) - x = reducer.multiply(x, g[nibble-1]); + x2 = reducer.multiply(x2, g[nibble-1]); } - return x; + + return reducer.multiply(x1, x2); } /* diff --git a/src/pubkey/elgamal/elg_op.cpp b/src/pubkey/elgamal/elg_op.cpp index 1e476ab7a..db828a300 100644 --- a/src/pubkey/elgamal/elg_op.cpp +++ b/src/pubkey/elgamal/elg_op.cpp @@ -1,11 +1,12 @@ /* * ElGamal Operations -* (C) 1999-2007 Jack Lloyd +* (C) 1999-2009 Jack Lloyd * * Distributed under the terms of the Botan license */ #include <botan/elg_op.h> +#include <botan/async.h> namespace Botan { @@ -33,8 +34,9 @@ SecureVector<byte> Default_ELG_Op::encrypt(const byte in[], u32bit length, if(m >= p) throw Invalid_Argument("Default_ELG_Op::encrypt: Input is too large"); - BigInt a = powermod_g_p(k); + auto future_a = std_async([&]() { return powermod_g_p(k); }); BigInt b = mod_p.multiply(m, powermod_y_p(k)); + BigInt a = future_a.get(); SecureVector<byte> output(2*p.bytes()); a.binary_encode(output + (p.bytes() - a.bytes())); diff --git a/src/pubkey/nr/nr_op.cpp b/src/pubkey/nr/nr_op.cpp index b5efa3d37..49aa9fc00 100644 --- a/src/pubkey/nr/nr_op.cpp +++ b/src/pubkey/nr/nr_op.cpp @@ -1,11 +1,12 @@ /* * NR Operations -* (C) 1999-2007 Jack Lloyd +* (C) 1999-2009 Jack Lloyd * * Distributed under the terms of the Botan license */ #include <botan/nr_op.h> +#include <botan/async.h> namespace Botan { @@ -37,7 +38,10 @@ SecureVector<byte> Default_NR_Op::verify(const byte in[], u32bit length) const if(c.is_zero() || c >= q || d >= q) throw Invalid_Argument("Default_NR_Op::verify: Invalid signature"); - BigInt i = mod_p.multiply(powermod_g_p(d), powermod_y_p(c)); + auto future_y_c = std_async([&]() { return powermod_y_p(c); }); + BigInt g_d = powermod_g_p(d); + + BigInt i = mod_p.multiply(g_d, future_y_c.get()); return BigInt::encode(mod_q.reduce(c - i)); } |