   //b3 45 f9 ... 58 75 75  32 bytes of encrypted body
   //00 00 2a  reset counter
   //00 03 19  message counter
-  //97 5b da ... 54 cb 8d  16 bytes of authentication tag
+  //29 3b 31 ... 68 0d cb  16 bytes of authentication tag
   //80  enc/auth type/format indicator.
   // Preshared ID prefix; only an initial part/prefix of this goes on the wire in the header.
   const uint8_t id[] = { 0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55 };

  //... b3 45 f9 29 69 57 0c b8 28 66 14 b4 f0 69 b0 08 71 da d8 fe 47 c1 c3 53 83 48 88 03 7d 58 75 75 | ...
  AssertIsEqual(0xb3, buf[8]); // 1st byte of encrypted body.
  AssertIsEqual(0x75, buf[39]); // 32nd/last byte of encrypted body.
  //... 00 00 2a 00 03 19 97 5b da df 92 08 42 b8 c1 3b dc 02 76 54 cb 8d 80
  AssertIsEqual(0x00, buf[40]); // 1st byte of counters.
  AssertIsEqual(0x00, buf[41]);
  AssertIsEqual(0x2a, buf[42]);
  AssertIsEqual(0x00, buf[43]); 
  AssertIsEqual(0x03, buf[44]);
  AssertIsEqual(0x19, buf[45]); // Last byte of counters.
  AssertIsEqual(0x97, buf[46]); // 1st byte of tag.
  AssertIsEqual(0x8d, buf[61]); // 16th/last byte of tag.
  AssertIsEqual(0x80, buf[62]); // enc format.
  // To decode, emulating RX, structurally validate unpack the header and extract the ID.
  OTRadioLink::SecurableFrameHeader sfhRX;

  Serial.println("SecureSmallFrameEncoding");
  uint8_t buf[OTRadioLink::SecurableFrameHeader::maxSmallFrameSize];
  //Example 3: secure, no valve, representative minimum stats {"b":1}).
  //Note that the sequence number must match the 4 lsbs of the message count, ie from iv[11].
  //and the ID is 0xaa 0xaa 0xaa 0xaa (transmitted) with the next ID bytes 0x55 0x55.
  //ResetCounter = 42
  //TxMsgCounter = 793
  //(Thus nonce/IV: aa aa aa aa 55 55 00 00 2a 00 03 19)
  //
  //3e cf 94 aa aa aa aa 20 | b3 45 f9 29 69 57 0c b8 28 66 14 b4 f0 69 b0 08 71 da d8 fe 47 c1 c3 53 83 48 88 03 7d 58 75 75 | 00 00 2a 00 03 19 29 3b 31 52 c3 26 d2 6d d0 8d 70 1e 4b 68 0d cb 80
  //
  //3e  length of header (62) after length byte 5 + (encrypted) body 32 + trailer 32
  //cf  'O' secure OpenTRV basic frame
