💳 Smart Card & NFC Tools
17 toolsAPDU Command Builder
Interactive Case 1–4 APDU construction with presets for SELECT, READ RECORD, GET DATA, and extended APDU.
PopularEMV TLV Parser & DOL Builder
BER-TLV decode with EMV tag search, PDOL/CDOL/DDOL construction for payment terminal development.
PopularATR Decoder
Parse ISO 7816-3 Answer-To-Reset: TS, T0, interface bytes, historical bytes. Auto-detect T=0/T=1.
GP Session Key Calculator
GlobalPlatform SCP02 3DES-CBC & SCP03 AES-CMAC session key derivation with MAC computation.
NDEF Message Parser
Parse and build NFC NDEF messages. All TNF types, chunked records, and URI/Text/Smart Poster records.
MIFARE Access Bits Calculator
Sector trailer C1/C2/C3 permissions. Access bytes 6–9 hex generator and reverse decoder.
🔒 Cryptography & Security
12 toolsCrypto Checksum Verifier
CRC-16/32, XOR LRC, 3DES Retail-MAC (ISO 9797-1 Alg 3), AES-CMAC (RFC 4493 / NIST SP 800-38B).
PopularKey Diversification Calculator
EMV CSK Option A/B, Visa SD, Mastercard CAP. 3DES/AES key derivation, all in-browser.
FIDO2 CBOR Attestation Parser
Parse WebAuthn attestation objects. authData, AAGUID, COSE key, packed/TPM attestation formats.
Session Key Visualizer
Step-by-step 3DES/AES session key derivation. SCP02/SCP03 compatible with intermediate values.
🔧 Encoding & Data Tools
7 toolsCRC Calculator
CRC-8/16/32/64 with 17 industry variants: MODBUS, XMODEM, Castagnoli, ECMA-182, and more. Hex & ASCII input.
NewLuhn Algorithm Validator
Validate credit cards, IMEI, ICCID, SIM numbers. Generate check digits and detect issuer from BIN prefix.
NewASN.1 DER Parser
Tree-view ASN.1 decoder with OID resolution. Parse X.509 certificates, PKCS structures, and CMS data.
Base64 Encoder / Decoder
Encode and decode Base64 text and binary data. Standard, URL-safe, and MIME variants supported.
NewHex Converter
Convert between hex, decimal, binary, octal. 8/16/32/64-bit signed/unsigned, big/little endian, ASCII hex, BCD EMV amount.
NewURL Encoder / Decoder
Encode and decode URLs with encodeURIComponent and encodeURI. Batch mode, reserved character reference, and double-encoding detection.
NewCBOR Decoder
Parse CBOR (RFC 8949) data from hex input. FIDO2 CTAP2, COSE, SenML, CDDL development tool.
New📚 Knowledge Base
In-depth tutorialsISO 7816 Protocol Reference
All 15 parts explained: physical characteristics, T=0/T=1 protocols, APDU structure, file system, secure messaging.
Read guide →APDU Commands Reference
Full CLA/INS/P1/P2 reference. All standard ISO 7816-4 commands with full SW1 SW2 status word dictionary.
Read guide →GlobalPlatform SCP02 vs SCP03
Deep comparison of secure channel protocols: 3DES vs AES, key derivation, MAC computation, security analysis.
Read guide →Java Card Applet Tutorial
Build your first Java Card applet: toolchain setup, APDU handling, secure messaging, GlobalPlatform deployment.
Read guide →Smart Card Filesystem Guide
SELECT, READ BINARY, READ RECORD in practice. MF/DF/EF hierarchy with real APDU trace examples.
Read guide →EMV Tag Reference
All EMV data objects with descriptions, encoding formats, and usage in Books 3 & 4 transaction processing.
Read guide →EMV ARQC & ARPC Cryptograms
How payment card cryptograms work: ARQC generation, ARPC validation, SDA/DDA/CDA, and the online authorization flow.
Read guide →YubiKey PIV for SSH Authentication
Set up YubiKey PIV for SSH: generate keys, configure PIN, export certs, and connect to servers with hardware-backed keys.
Read guide →FIDO2 vs U2F — What Changed
FIDO2 vs U2F protocol differences, CTAP1 vs CTAP2, resident keys, and why U2F-only keys are obsolete.
Read comparison →Smart Card vs Security Key
ISO 7816 smart cards vs FIDO2 security keys: protocols, use cases, and the YubiKey that does both.
Read comparison →
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