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Make nonce a class member rather than temporary 

Effectively this creates a workspace for encrypting the nonce. The zeroizer will run when the class is destroyed, rather than each invocation of UncheckedSetKey.
Performance went from 3.6 cpb as a temporary to 2.9 cpb as a class member
pull/461/head
Jeffrey Walton 2017-08-05 06:05:57 -04:00
parent bf35d58ad7
commit 0357e508e4
No known key found for this signature in database
GPG Key ID: B36AB348921B1838
2 changed files with 7 additions and 7 deletions
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12
poly1305.cpp
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@ -33,13 +33,13 @@ void Poly1305_Base<T>::UncheckedSetKey(const byte *key, unsigned int length, con
ConstByteArrayParameter t; ConstByteArrayParameter t;
if (params.GetValue(Name::IV(), t) && t.begin() && t.size()) if (params.GetValue(Name::IV(), t) && t.begin() && t.size())
{ {
SecByteBlock nk(16); // Nonce key is a class member to avoid the zeroizer on a temporary
m_cipher.ProcessBlock(t.begin(), nk); m_cipher.ProcessBlock(t.begin(), m_nk.begin());
m_n[0] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, nk + 0); m_n[0] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, m_nk + 0);
m_n[1] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, nk + 4); m_n[1] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, m_nk + 4);
m_n[2] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, nk + 8); m_n[2] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, m_nk + 8);
m_n[3] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, nk + 12); m_n[3] = GetWord<word32>(false, LITTLE_ENDIAN_ORDER, m_nk + 12);
m_used = false; m_used = false;
} }

2
poly1305.h
View File

@ -93,7 +93,7 @@ protected:
FixedSizeAlignedSecBlock<word32, 4> m_n; FixedSizeAlignedSecBlock<word32, 4> m_n;
// Accumulated message bytes and index // Accumulated message bytes and index
FixedSizeAlignedSecBlock<byte, BLOCKSIZE> m_acc; FixedSizeAlignedSecBlock<byte, BLOCKSIZE> m_acc, m_nk;
size_t m_idx; size_t m_idx;
// Track nonce reuse; assert in debug but continue // Track nonce reuse; assert in debug but continue