Update comments

Reference the bug report in DL_SignerBase::SignAndRestart for future readers

1 files changed, 5 insertions, 3 deletions

diff --git a/pubkey.h b/pubkey.h
index 41249448..654df8c3 100644
--- a/pubkey.h
+++ b/pubkey.h
@@ -1604,8 +1604,8 @@ public:
 		if (rng.CanIncorporateEntropy())

 			rng.IncorporateEntropy(representative, representative.size());

 

+		Integer k, ks;

 		const Integer& q = params.GetSubgroupOrder();

-		Integer k;

 		if (alg.IsDeterministic())

 		{

 			const Integer& x = key.GetPrivateExponent();

@@ -1617,7 +1617,9 @@ public:
 			k.Randomize(rng, 1, params.GetSubgroupOrder()-1);

 		}

 

-		Integer ks = k + q;

+		// Due to timing attack on nonce length by Jancar

+		// https://github.com/weidai11/cryptopp/issues/869

+		ks = k + q;

 		if (ks.BitCount() == q.BitCount()) {

 			ks += q;

 		}

@@ -1635,7 +1637,7 @@ public:
 		alg.Sign(params, key.GetPrivateExponent(), ma.m_k, e, r, s);

 		*/

 

-		size_t rLen = alg.RLen(params);

+		const size_t rLen = alg.RLen(params);

 		r.Encode(signature, rLen);

 		s.Encode(signature+rLen, alg.SLen(params));