diff options
| -rw-r--r-- | src/aead/gcm/gcm.cpp | 27 |
1 files changed, 12 insertions, 15 deletions
diff --git a/src/aead/gcm/gcm.cpp b/src/aead/gcm/gcm.cpp index 7b04f6f48..7b8e0aa36 100644 --- a/src/aead/gcm/gcm.cpp +++ b/src/aead/gcm/gcm.cpp @@ -14,15 +14,14 @@ namespace Botan { namespace { -secure_vector<byte> -gcm_multiply(const secure_vector<byte>& x, - const secure_vector<byte>& y) +void gcm_multiply(secure_vector<byte>& x, + const secure_vector<byte>& h) { static const u64bit R = 0xE100000000000000; - u64bit V[2] = { - load_be<u64bit>(&y[0], 0), - load_be<u64bit>(&y[0], 1) + u64bit H[2] = { + load_be<u64bit>(&h[0], 0), + load_be<u64bit>(&h[0], 1) }; u64bit Z[2] = { 0, 0 }; @@ -37,20 +36,18 @@ gcm_multiply(const secure_vector<byte>& x, { if((X >> (63-j)) & 1) { - Z[0] ^= V[0]; - Z[1] ^= V[1]; + Z[0] ^= H[0]; + Z[1] ^= H[1]; } - const u64bit r = (V[1] & 1) ? R : 0; + const u64bit r = (H[1] & 1) ? R : 0; - V[1] = (V[0] << 63) | (V[1] >> 1); - V[0] = (V[0] >> 1) ^ r; + H[1] = (H[0] << 63) | (H[1] >> 1); + H[0] = (H[0] >> 1) ^ r; } } - secure_vector<byte> out(16); - store_be<u64bit>(&out[0], Z[0], Z[1]); - return out; + store_be<u64bit>(&x[0], Z[0], Z[1]); } void ghash_update(const secure_vector<byte>& H, @@ -69,7 +66,7 @@ void ghash_update(const secure_vector<byte>& H, xor_buf(&ghash[0], &input[0], to_proc); - ghash = gcm_multiply(ghash, H); + gcm_multiply(ghash, H); input += to_proc; length -= to_proc; |