SDM Encoding

Programming SDM

encodeTag(profile, params?)

Configure the tag for Secure Dynamic Messaging (auth: Key 0, automatic). This is the main “program a tag” entry point. profile is 'plain', 'encrypted', or 'full'.

Param	Default	Meaning
resetCounter	false	Reset SDM counter before encoding
ndefType	'url'	'url' or 'text'
url	—	Required when ndefType='url' (with ndefType='text' the tag builds its own JSON — no text input)
counterLimit	null	Counter cap (1–16777215)
fileData	'SecureData123456'	Static plain (UTF-8) string for the 'full' profile, space-padded to encSize/2 bytes before encryption
encSize	32	Encryption size for 'full': 32, 64, or 128
enableTTStatus	false	Mirror TagTamper status (full profile, TagTamper variant)
compressed	false	Shorter URLs without parameter names
sdmSettings	null	Advanced SDM access-rights override

// plain — UID + counter + CMAC mirrored in cleartext
await tag.encodeTag('plain', { url: 'https://example.com/t' });

// encrypted — PICCData (UID + counter) encrypted + CMAC
await tag.encodeTag('encrypted', { url: 'https://example.com/t' });

// full — encrypted PICCData + encrypted file data + CMAC
const res = await tag.encodeTag('full', {
  url: 'https://example.com/t',
  fileData: 'HelloWorld!',
  encSize: 32,
});

Returns

{
  success: true,
  data: {
    profile: 'full',
    compressed: false,
    pattern: 'https://example.com/t?picc_data=00000000000000000000000000000000&enc=00000000000000000000000000000000&cmac=0000000000000000',
    counterLimit: null,
    sdmSettings: null,
    piccDataSize: 32,
    fileData: 'HelloWorld!     ',  // input space-padded to encSize/2 = 16 bytes (plain UTF-8, not hex)
    enableTTStatus: false
  },
  duration: 38
}

Turning SDM Off

disableSDM(fileNo?)

Disable SDM on a file (back to plain mode, default access rights, counter reset). fileNo defaults to 2 (NDEF).

const res = await tag.disableSDM();

Returns

{
  success: true,
  data: { enabled: false },
  duration: 21
}