Construction

Verifies the SDM output a tag emits — no hardware. Construct once with your keys and SDM settings, then call the decode* method matching the tag’s profile.

import { CrypTagDecoder } from 'cryptag';

Creating a Decoder

new CrypTagDecoder(options?)

Construct a decoder with your keys and SDM settings. Throws if a key config or SDM setting is invalid.

• options.keyList — { '0'..'4': { masterKey: '<32 hex>', diversify: boolean } }. Missing slots default to the factory key, non-diversified.
• options.systemIdentifier (default 'CRYPTAG') — for diversification.
• options.applicationId (default '3042F5') — for diversification.
• options.sdmSettings.sdmMetaRead (number|'free', default 2) — key for PICCData decryption.
• options.sdmSettings.sdmFileRead (number|'free', default 3) — key for the MAC / file-data.
• options.sdmSettings.cmacSeparator (default '') — the URL separator preceding the CMAC; it is part of the full-profile MAC input, so it must match how the URL was encoded.

const decoder = new CrypTagDecoder({
  keyList: {
    '2': { masterKey: '00000000000000000000000000000000', diversify: false },
    '3': { masterKey: '00000000000000000000000000000000', diversify: false },
  },
  systemIdentifier: 'CRYPTAG',
  applicationId: '3042F5',
  sdmSettings: { sdmMetaRead: 2, sdmFileRead: 3, cmacSeparator: '&cmac=' },
});

The constructor returns a CrypTagDecoder instance — call the decode* method matching the tag’s profile on it.