ASN.1 Parser

ASN.1 Parser

Decode and inspect ASN.1 (Abstract Syntax Notation One) encoded data used in X.509 certificates, PKCS structures, and cryptographic protocols. Paste hex, base64, or PEM-encoded data and instantly see the full parsed structure.

How to Use

1. Paste your ASN.1 data in hex, base64, or PEM format into the input field.

2. The parser auto-detects the input format and decodes the TLV (Tag-Length-Value) structure.

3. View the parsed output showing tag types, lengths, and values with nested indentation.

4. OIDs are displayed in both numeric and human-readable named format.

5. Export the parsed structure as JSON or copy the output to clipboard.

Features

• DER/BER Decoding – Parse binary ASN.1 structures with full Tag-Length-Value breakdown
• Multiple Input Formats – Accept hex strings, base64, or PEM-encoded data with auto-detection
• OID Resolution – Map Object Identifiers to human-readable names (X.509, PKCS, hash algorithms)
• Nested Structure – Indented display for SEQUENCE, SET, and other constructed types
• All Universal Tags – SEQUENCE, INTEGER, OCTET STRING, BIT STRING, BOOLEAN, NULL, OID, UTF8String, PrintableString, and more
• JSON Export – Export the parsed tree structure as JSON for further processing
• Client-Side Only – All parsing happens in your browser; no data leaves your machine