ASN.1 DER Parser
Parse ASN.1 DER-encoded data with interactive tree view. Supports all standard ASN.1 types: SEQUENCE, SET, INTEGER, OID, BIT STRING, OCTET STRING, UTCTime, GeneralizedTime, PrintableString, UTF8String, and more. Decode X.509 certificates, PKCS#7/CMS, PKCS#12/PFX, and CRLs — all in-browser. No data leaves your device.
DER Input (Hex or Base64)
Parsed Structure
Paste DER data and click Parse DER
How to Use This Parser
Input: Paste hex-encoded DER bytes, or Base64-encoded DER (commonly found in PEM files between "-----BEGIN" lines).
Output: Interactive tree showing every TLV in the structure. Click to expand/collapse containers (SEQUENCE/SET). OIDs are automatically decoded to their human-readable names.
Related Tools
X.509 Certificate Parser (Chinese) | EMV TLV Parser | APDU Command Builder