Add eddsa from ref10 implementation (with some modifications).

core/crypto/EdDSA25519.h

@@ -0,0 +1,49 @@
+#ifndef EDDSA25519_H__
+#define EDDSA25519_H__
+
+#include "SignatureBase.h"
+
+namespace i2p {
+namespace crypto {
+
+// EdDSA
+const size_t EDDSA25519_PUBLIC_KEY_LENGTH = 32;
+const size_t EDDSA25519_SIGNATURE_LENGTH = 64;
+const size_t EDDSA25519_PRIVATE_KEY_LENGTH = 32;        
+
+class EDDSA25519Verifier : public Verifier {
+public:
+
+    EDDSA25519Verifier(const uint8_t* signingKey);
+    bool Verify(const uint8_t* buf, size_t len, const uint8_t* signature) const;
+
+    size_t GetPublicKeyLen() const;
+    size_t GetSignatureLen() const;
+
+private:
+
+    uint8_t m_PublicKey[EDDSA25519_PUBLIC_KEY_LENGTH];
+};
+
+class EDDSA25519Signer : public Signer {
+public:
+
+    /**
+     * @todo allow passing the public key too as an optimization
+     */
+    EDDSA25519Signer(const uint8_t * signingPrivateKey);
+
+    /**
+     * @todo do not pass random number generator, EdDSA does not require a random
+     *  source
+     */
+    void Sign(CryptoPP::RandomNumberGenerator& rnd, const uint8_t* buf, int len, uint8_t* signature) const; 
+
+    uint8_t m_PrivateKey[EDDSA25519_PRIVATE_KEY_LENGTH];
+    uint8_t m_PublicKey[EDDSA25519_PUBLIC_KEY_LENGTH];
+};
+
+}
+}
+
+#endif // EDDSA25519_H__