Experimental serial comm concept for STM (unfinished)

templates/blackpill/Inc/api.h

+#define CRYPTO_KEYBYTES 16
+#define CRYPTO_NSECBYTES 0 
+#define CRYPTO_NPUBBYTES 16 
+#define CRYPTO_ABYTES 16 
+#define CRYPTO_NOOVERLAP 1 

templates/blackpill/Inc/crypto_aead.h

+int crypto_aead_encrypt(
+	unsigned char *c,unsigned long long *clen,
+	const unsigned char *m,unsigned long long mlen,
+	const unsigned char *ad,unsigned long long adlen,
+	const unsigned char *nsec,
+	const unsigned char *npub,
+	const unsigned char *k
+	); 
+
+
+int crypto_aead_decrypt(
+	unsigned char *m,unsigned long long *outputmlen,
+	unsigned char *nsec,
+	const unsigned char *c,unsigned long long clen,
+	const unsigned char *ad,unsigned long long adlen,
+	const unsigned char *npub,
+	const unsigned char *k
+	); 
+