Add SecretToPublicKey function for ed25519

Also remove IsClamped. Clamping occurs with ed25519, but it happens inside the Donna code. It is not needed elsewhere for ed25519.

1 files changed, 10 insertions, 22 deletions

diff --git a/xed25519.cpp b/xed25519.cpp
index f8544f34..78d0f53d 100644
--- a/xed25519.cpp
+++ b/xed25519.cpp
@@ -365,18 +365,12 @@ bool x25519::Agree(byte *agreedValue, const byte *privateKey, const byte *otherP
 

 // ******************** ed25519 Signer ************************* //

 

-void ed25519PrivateKey::ClampKeys(byte y[PUBLIC_KEYLENGTH], byte x[SECRET_KEYLENGTH]) const

+void ed25519PrivateKey::SecretToPublicKey(byte y[PUBLIC_KEYLENGTH], const byte x[SECRET_KEYLENGTH]) const

 {

-    x[0] &= 248; x[31] &= 127; x[31] |= 64;

     int ret = Donna::ed25519_publickey(y, x);

     CRYPTOPP_ASSERT(ret == 0); CRYPTOPP_UNUSED(ret);

 }

 

-bool ed25519PrivateKey::IsClamped(const byte x[SECRET_KEYLENGTH]) const

-{

-    return (x[0] & 248) == x[0] && (x[31] & 127) == x[31] && (x[31] | 64) == x[31];

-}

-

 bool ed25519PrivateKey::IsSmallOrder(const byte y[PUBLIC_KEYLENGTH]) const

 {

     return HasSmallOrder(y);

@@ -385,17 +379,14 @@ bool ed25519PrivateKey::IsSmallOrder(const byte y[PUBLIC_KEYLENGTH]) const
 bool ed25519PrivateKey::Validate(RandomNumberGenerator &rng, unsigned int level) const

 {

     CRYPTOPP_UNUSED(rng);

-    CRYPTOPP_ASSERT(IsClamped(m_sk) == true);

     CRYPTOPP_ASSERT(IsSmallOrder(m_pk) == false);

 

-    if (level >= 1 && IsClamped(m_sk) == false)

-        return false;

-    if (level >= 2 && IsSmallOrder(m_pk) == true)

+    if (level >= 1 && IsSmallOrder(m_pk) == true)

         return false;

     if (level >= 3)

     {

         SecByteBlock sk(m_sk, SECRET_KEYLENGTH), pk(PUBLIC_KEYLENGTH);

-        ClampKeys(pk, sk);

+        SecretToPublicKey(pk, sk);

 

         // Secret key is already clamped, bufs are equal

         if (VerifyBufsEqual(pk, m_pk, PUBLIC_KEYLENGTH) == false)

@@ -454,11 +445,10 @@ void ed25519PrivateKey::AssignFrom(const NameValuePairs &source)
         m_oid = oid;

     }

 

-    bool clamp = false;

-    if (source.GetValue("Clamp", clamp) && clamp == true)

-        ClampKeys(m_pk, m_sk);

+    bool derive = false;

+    if (source.GetValue("DerivePublicKey", derive) && derive == true)

+        SecretToPublicKey(m_pk, m_sk);

 

-    CRYPTOPP_ASSERT(IsClamped(m_sk) == true);

     CRYPTOPP_ASSERT(IsSmallOrder(m_pk) == false);

 }

 

@@ -469,7 +459,6 @@ void ed25519PrivateKey::GenerateRandom(RandomNumberGenerator &rng, const NameVal
         rng.IncorporateEntropy(seed.begin(), seed.size());

 

     rng.GenerateBlock(m_sk, SECRET_KEYLENGTH);

-    m_sk[0] &= 248; m_sk[31] &= 127; m_sk[31] |= 64;

     int ret = Donna::ed25519_publickey(m_pk, m_sk);

     CRYPTOPP_ASSERT(ret == 0); CRYPTOPP_UNUSED(ret);

 }

@@ -537,7 +526,6 @@ void ed25519PrivateKey::BERDecode(BufferedTransformation &bt)
     if (generatePublicKey)

         Donna::ed25519_publickey(m_pk, m_sk);

 

-    CRYPTOPP_ASSERT(IsClamped(m_sk) == true);

     CRYPTOPP_ASSERT(IsSmallOrder(m_pk) == false);

 }

 

@@ -601,7 +589,7 @@ void ed25519PrivateKey::SetPrivateExponent (const byte x[SECRET_KEYLENGTH])
 {

     AssignFrom(MakeParameters

         (Name::PrivateExponent(), ConstByteArrayParameter(x, SECRET_KEYLENGTH))

-        ("Clamp", true));

+        ("DerivePublicKey", true));

 }

 

 void ed25519PrivateKey::SetPrivateExponent (const Integer &x)

@@ -613,7 +601,7 @@ void ed25519PrivateKey::SetPrivateExponent (const Integer &x)
 

     AssignFrom(MakeParameters

         (Name::PrivateExponent(), ConstByteArrayParameter(bx, SECRET_KEYLENGTH, false))

-        ("Clamp", true));

+        ("DerivePublicKey", true));

 }

 

 const Integer& ed25519PrivateKey::GetPrivateExponent() const

@@ -635,7 +623,7 @@ ed25519Signer::ed25519Signer(const byte x[SECRET_KEYLENGTH])
 {

     AccessPrivateKey().AssignFrom(MakeParameters

         (Name::PrivateExponent(), ConstByteArrayParameter(x, SECRET_KEYLENGTH, false))

-        ("Clamp", true));

+        ("DerivePublicKey", true));

 }

 

 ed25519Signer::ed25519Signer(const Integer &y, const Integer &x)

@@ -661,7 +649,7 @@ ed25519Signer::ed25519Signer(const Integer &x)
 

     AccessPrivateKey().AssignFrom(MakeParameters

         (Name::PrivateExponent(), ConstByteArrayParameter(bx, SECRET_KEYLENGTH, false))

-        ("Clamp", true));

+        ("DerivePublicKey", true));

 }

 

 ed25519Signer::ed25519Signer(RandomNumberGenerator &rng)