Add support for RFC 8032 Ed25519ph

GH #1699

3 files changed, 47 insertions, 13 deletions

diff --git a/src/lib/pubkey/ed25519/ed25519.cpp b/src/lib/pubkey/ed25519/ed25519.cpp
index b75028041..624f82657 100644
--- a/src/lib/pubkey/ed25519/ed25519.cpp
+++ b/src/lib/pubkey/ed25519/ed25519.cpp
@@ -34,8 +34,9 @@ void ed25519_gen_keypair(uint8_t* pk, uint8_t* sk, const uint8_t seed[32])
    }
 
 void ed25519_sign(uint8_t sig[64],
-                  const uint8_t* m, size_t mlen,
-                  const uint8_t* sk)
+                  const uint8_t m[], size_t mlen,
+                  const uint8_t sk[64],
+                  const uint8_t domain_sep[], size_t domain_sep_len)
    {
    uint8_t az[64];
    uint8_t nonce[64];
@@ -49,6 +50,7 @@ void ed25519_sign(uint8_t sig[64],
    az[31] &= 63;
    az[31] |= 64;
 
+   sha.update(domain_sep, domain_sep_len);
    sha.update(az + 32, 32);
    sha.update(m, mlen);
    sha.final(nonce);
@@ -56,6 +58,7 @@ void ed25519_sign(uint8_t sig[64],
    sc_reduce(nonce);
    ge_scalarmult_base(sig, nonce);
 
+   sha.update(domain_sep, domain_sep_len);
    sha.update(sig, 32);
    sha.update(sk + 32, 32);
    sha.update(m, mlen);
@@ -67,7 +70,8 @@ void ed25519_sign(uint8_t sig[64],
 
 bool ed25519_verify(const uint8_t* m, size_t mlen,
                     const uint8_t sig[64],
-                    const uint8_t* pk)
+                    const uint8_t* pk,
+                    const uint8_t domain_sep[], size_t domain_sep_len)
    {
    uint8_t h[64];
    uint8_t rcheck[32];
@@ -83,6 +87,7 @@ bool ed25519_verify(const uint8_t* m, size_t mlen,
       return false;
       }
 
+   sha.update(domain_sep, domain_sep_len);
    sha.update(sig, 32);
    sha.update(pk, 32);
    sha.update(m, mlen);
diff --git a/src/lib/pubkey/ed25519/ed25519.h b/src/lib/pubkey/ed25519/ed25519.h
index 51c75e641..97ed023f2 100644
--- a/src/lib/pubkey/ed25519/ed25519.h
+++ b/src/lib/pubkey/ed25519/ed25519.h
@@ -99,12 +99,14 @@ void ed25519_gen_keypair(uint8_t pk[32], uint8_t sk[64], const uint8_t seed[32])
 void ed25519_sign(uint8_t sig[64],
                   const uint8_t msg[],
                   size_t msg_len,
-                  const uint8_t sk[64]);
+                  const uint8_t sk[64],
+                  const uint8_t domain_sep[], size_t domain_sep_len);
 
 bool ed25519_verify(const uint8_t msg[],
                     size_t msg_len,
                     const uint8_t sig[64],
-                    const uint8_t pk[32]);
+                    const uint8_t pk[32],
+                    const uint8_t domain_sep[], size_t domain_sep_len);
 
 }
 
diff --git a/src/lib/pubkey/ed25519/ed25519_key.cpp b/src/lib/pubkey/ed25519/ed25519_key.cpp
index 1de24aa26..c4b260c4c 100644
--- a/src/lib/pubkey/ed25519/ed25519_key.cpp
+++ b/src/lib/pubkey/ed25519/ed25519_key.cpp
@@ -122,7 +122,7 @@ class Ed25519_Pure_Verify_Operation final : public PK_Ops::Verification
 
          const std::vector<uint8_t>& pub_key = m_key.get_public_key();
          BOTAN_ASSERT_EQUAL(pub_key.size(), 32, "Expected size");
-         const bool ok = ed25519_verify(m_msg.data(), m_msg.size(), sig, pub_key.data());
+         const bool ok = ed25519_verify(m_msg.data(), m_msg.size(), sig, pub_key.data(), nullptr, 0);
          m_msg.clear();
          return ok;
          }
@@ -138,9 +138,18 @@ class Ed25519_Pure_Verify_Operation final : public PK_Ops::Verification
 class Ed25519_Hashed_Verify_Operation final : public PK_Ops::Verification
    {
    public:
-      Ed25519_Hashed_Verify_Operation(const Ed25519_PublicKey& key, const std::string& hash) : m_key(key)
+      Ed25519_Hashed_Verify_Operation(const Ed25519_PublicKey& key, const std::string& hash, bool rfc8032) :
+         m_key(key)
          {
          m_hash = HashFunction::create_or_throw(hash);
+
+         if(rfc8032)
+            {
+            m_domain_sep = {
+               0x53, 0x69, 0x67, 0x45, 0x64, 0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x6E, 0x6F, 0x20, 0x45, 0x64,
+               0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x63, 0x6F, 0x6C, 0x6C, 0x69, 0x73, 0x69, 0x6F, 0x6E, 0x73,
+               0x01, 0x00 };
+            }
          }
 
       void update(const uint8_t msg[], size_t msg_len) override
@@ -157,12 +166,13 @@ class Ed25519_Hashed_Verify_Operation final : public PK_Ops::Verification
 
          const std::vector<uint8_t>& pub_key = m_key.get_public_key();
          BOTAN_ASSERT_EQUAL(pub_key.size(), 32, "Expected size");
-         return ed25519_verify(msg_hash.data(), msg_hash.size(), sig, pub_key.data());
+         return ed25519_verify(msg_hash.data(), msg_hash.size(), sig, pub_key.data(), m_domain_sep.data(), m_domain_sep.size());
          }
 
    private:
       std::unique_ptr<HashFunction> m_hash;
       const Ed25519_PublicKey& m_key;
+      std::vector<uint8_t> m_domain_sep;
    };
 
 /**
@@ -183,7 +193,7 @@ class Ed25519_Pure_Sign_Operation final : public PK_Ops::Signature
       secure_vector<uint8_t> sign(RandomNumberGenerator&) override
          {
          secure_vector<uint8_t> sig(64);
-         ed25519_sign(sig.data(), m_msg.data(), m_msg.size(), m_key.get_private_key().data());
+         ed25519_sign(sig.data(), m_msg.data(), m_msg.size(), m_key.get_private_key().data(), nullptr, 0);
          m_msg.clear();
          return sig;
          }
@@ -201,9 +211,18 @@ class Ed25519_Pure_Sign_Operation final : public PK_Ops::Signature
 class Ed25519_Hashed_Sign_Operation final : public PK_Ops::Signature
    {
    public:
-      Ed25519_Hashed_Sign_Operation(const Ed25519_PrivateKey& key, const std::string& hash) : m_key(key)
+      Ed25519_Hashed_Sign_Operation(const Ed25519_PrivateKey& key, const std::string& hash, bool rfc8032) :
+         m_key(key)
          {
          m_hash = HashFunction::create_or_throw(hash);
+
+         if(rfc8032)
+            {
+            m_domain_sep = std::vector<uint8_t>{
+               0x53, 0x69, 0x67, 0x45, 0x64, 0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x6E, 0x6F, 0x20, 0x45, 0x64,
+               0x32, 0x35, 0x35, 0x31, 0x39, 0x20, 0x63, 0x6F, 0x6C, 0x6C, 0x69, 0x73, 0x69, 0x6F, 0x6E, 0x73,
+               0x01, 0x00 };
+            }
          }
 
       size_t signature_length() const override { return 64; }
@@ -218,13 +237,17 @@ class Ed25519_Hashed_Sign_Operation final : public PK_Ops::Signature
          secure_vector<uint8_t> sig(64);
          std::vector<uint8_t> msg_hash(m_hash->output_length());
          m_hash->final(msg_hash.data());
-         ed25519_sign(sig.data(), msg_hash.data(), msg_hash.size(), m_key.get_private_key().data());
+         ed25519_sign(sig.data(),
+                      msg_hash.data(), msg_hash.size(),
+                      m_key.get_private_key().data(),
+                      m_domain_sep.data(), m_domain_sep.size());
          return sig;
          }
 
    private:
       std::unique_ptr<HashFunction> m_hash;
       const Ed25519_PrivateKey& m_key;
+      std::vector<uint8_t> m_domain_sep;
    };
 
 }
@@ -237,8 +260,10 @@ Ed25519_PublicKey::create_verification_op(const std::string& params,
       {
       if(params == "" || params == "Identity" || params == "Pure")
          return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Pure_Verify_Operation(*this));
+      else if(params == "Ed25519ph")
+         return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Hashed_Verify_Operation(*this, "SHA-512", true));
       else
-         return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Hashed_Verify_Operation(*this, params));
+         return std::unique_ptr<PK_Ops::Verification>(new Ed25519_Hashed_Verify_Operation(*this, params, false));
       }
    throw Provider_Not_Found(algo_name(), provider);
    }
@@ -252,8 +277,10 @@ Ed25519_PrivateKey::create_signature_op(RandomNumberGenerator&,
       {
       if(params == "" || params == "Identity" || params == "Pure")
          return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Pure_Sign_Operation(*this));
+      else if(params == "Ed25519ph")
+         return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Hashed_Sign_Operation(*this, "SHA-512", true));
       else
-         return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Hashed_Sign_Operation(*this, params));
+         return std::unique_ptr<PK_Ops::Signature>(new Ed25519_Hashed_Sign_Operation(*this, params, false));
       }
    throw Provider_Not_Found(algo_name(), provider);
    }