Fix K1/K2 use in the comments in ChaCha20-Poly1305 AEAD

This is done for the ChaCha20-Poly1305 AEAD test vector
and for the K1/K2 ChaCha20 cipher instances in chacha_poly_aead.h

Author: stratospher

src/crypto/chacha_poly_aead.h

@@ -117,8 +117,8 @@ static constexpr int AAD_PACKAGES_PER_ROUND = 21;        /* 64 / 3 round down*/
 class ChaCha20Poly1305AEAD
 {
 private:
-    ChaCha20 m_chacha_main;                                      // payload and poly1305 key-derivation cipher instance
-    ChaCha20 m_chacha_header;                                    // AAD cipher instance (encrypted length)
+    ChaCha20 m_chacha_header;                                    // AAD cipher instance (encrypted length) and poly1305 key-derivation cipher instance
+    ChaCha20 m_chacha_main;                                      // payload
     unsigned char m_aad_keystream_buffer[CHACHA20_ROUND_OUTPUT]; // aad keystream cache
     uint64_t m_cached_aad_seqnr;                                 // aad keystream cache hint
 

src/test/crypto_tests.cpp

@@ -694,8 +694,8 @@ BOOST_AUTO_TEST_CASE(chacha20_poly1305_aead_testvector)
 
     TestChaCha20Poly1305AEAD(true, 0,
         /* m  */ "0000000000000000000000000000000000000000000000000000000000000000",
-        /* k1 (payload) */ "0000000000000000000000000000000000000000000000000000000000000000",
-        /* k2 (AAD) */ "0000000000000000000000000000000000000000000000000000000000000000",
+        /* k1 (AAD) */ "0000000000000000000000000000000000000000000000000000000000000000",
+        /* k2 (payload) */ "0000000000000000000000000000000000000000000000000000000000000000",
         /* AAD keystream */ "76b8e0ada0f13d90405d6ae55386bd28bdd219b8a08ded1aa836efcc8b770dc7da41597c5157488d7724e03fb8d84a376a43b8f41518a11cc387b669b2ee6586",
         /* encrypted message & MAC */ "76b8e09f07e7be5551387a98ba977c732d080dcb0f29a048e3656912c6533e32d2fc11829c1b6c1df1f551cd6131ff08",
         /* encrypted message & MAC at sequence 999 */ "b0a03d5bd2855d60699e7d3a3133fa47be740fe4e4c1f967555e2d9271f31c3aaa7aa16ec62c5e24f040c08bb20c3598");