ASN.1 BER/DER Parser
Walk any BER/DER-encoded ASN.1 tree (X.690). Tags, lengths, types, and value previews; OBJECT IDENTIFIERs are looked up against a built-in dictionary. Useful when you have raw bytes and need to know what they are. Accepts hex, bare base64, or a PEM block.
Input
Result
Paste, drop, or pick a file.
All parsing runs locally.
About ASN.1 / BER / DER
ASN.1 (Abstract Syntax Notation One) describes the abstract structure; BER/DER is the concrete byte encoding (a tag, a length, and a value, recursively). DER is the canonical, deterministic flavour used by X.509, PKCS#7, PKCS#10, PKCS#12 and friends. Defined by ITU-T X.690.
Spec
X.690 (BER/CER/DER) and X.680 (ASN.1).
Companion tool
For BER-TLV (smart-card flavour, slightly different conventions): use the TLV parser.