Make significant_words const time also

Only used in one place, where const time doesn't matter, but can't hurt.

Remove low_bit, can be replaced by ctz.

1 files changed, 3 insertions, 3 deletions

diff --git a/src/lib/modes/aead/ocb/ocb.cpp b/src/lib/modes/aead/ocb/ocb.cpp
index 866527800..b25abbe6a 100644
--- a/src/lib/modes/aead/ocb/ocb.cpp
+++ b/src/lib/modes/aead/ocb/ocb.cpp
@@ -69,7 +69,7 @@ class L_computer final
                // ntz(4*i+2) == 1
                // ntz(4*i+3) == 0
                block_index += 4;
-               const size_t ntz4 = ctz<uint32_t>(static_cast<uint32_t>(block_index));
+               const size_t ntz4 = var_ctz32(static_cast<uint32_t>(block_index));
 
                xor_buf(offsets, m_offset.data(), L0.data(), m_BS);
                offsets += m_BS;
@@ -91,7 +91,7 @@ class L_computer final
 
          for(size_t i = 0; i != blocks; ++i)
             { // could be done in parallel
-            const size_t ntz = ctz<uint32_t>(static_cast<uint32_t>(block_index + i + 1));
+            const size_t ntz = var_ctz32(static_cast<uint32_t>(block_index + i + 1));
             xor_buf(m_offset.data(), get(ntz).data(), m_BS);
             copy_mem(offsets, m_offset.data(), m_BS);
             offsets += m_BS;
@@ -136,7 +136,7 @@ secure_vector<uint8_t> ocb_hash(const L_computer& L,
    for(size_t i = 0; i != ad_blocks; ++i)
       {
       // this loop could run in parallel
-      offset ^= L.get(ctz<uint32_t>(static_cast<uint32_t>(i+1)));
+      offset ^= L.get(var_ctz32(static_cast<uint32_t>(i+1)));
       buf = offset;
       xor_buf(buf.data(), &ad[BS*i], BS);
       cipher.encrypt(buf);