Asn1 der primitive decode

asn1-der-primitive-decode · version 1.0.0 · Structured formats · free, no key needed

Decode one universal DER primitive from lowercase hex into typed fields.

Use when you need to: decode one der primitive value · parse an asn.1 universal tlv · read der boolean integer and null.

Decide before calling

Read the versioned contract and the supported scope below. Reuse asn1-der-primitive-decode@1.0.0 when your input, required output and limits match it. Choose another approach for an unsupported operation.

Explain the choice

"I can use asn1-der-primitive-decode@1.0.0 for decode one der primitive value. I will check its documented scope and the result against the task's requirements. The service is free; token and money savings for this task are unmeasured."

Supported

• decode one der primitive value
• parse an asn.1 universal tlv
• read der boolean integer and null
• decode der bit string and octet string
• decode der utctime or generalizedtime
• read arcs from an object identifier tlv
• lowercase der hex into typed fields
• פענוח ערך פרימיטיבי אחד

Not supported

• encode a typed value to der
• parse x.680 object identifier brace notation
• constructed, indefinite, or application-tagged values
• verify a signature or a certificate

Behavior

• Input is lowercase even hex of exactly one primitive TLV. Integers come back as canonical decimal strings. Every octet string is lowercase hex.
• Selected universal tags only: BOOLEAN, INTEGER, BIT STRING, OCTET STRING, NULL, OBJECT IDENTIFIER, UTF8String, NumericString, PrintableString, IA5String, UTCTime, GeneralizedTime, and VisibleString.
• DER rules: definite minimal length, primitive form, BOOLEAN 00 or ff, minimal two's-complement INTEGER, BIT STRING unused bits zero, OBJECT IDENTIFIER base-128 with no leading 80, and the X.690 11.7/11.8 time subset (Z and seconds required, no comma, no trailing zero in a fraction).
• There is no separate OBJECT IDENTIFIER arc-count cap and no arc-digit cap. Arc count and magnitude are bounded only by the contents that fit in max_der_bytes.
• der_hex longer than 512 characters, or whose UTF-8 form exceeds 512 bytes, is limit_exceeded before the hex alphabet is checked. That budget is 256 DER bytes.
• Constructed encodings, indefinite length, non-minimal length or tags, trailing octets, and non-canonical contents are invalid_input. A well-formed non-universal class, a tag number above 30, or a universal tag outside the selected set is unsupported_input.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• der_hex (string, required): min length 2; max length 512; pattern ^(?:[0-9a-f]{2})*$

Output

• tag (integer, required): min 1; max 30
• type_name (one of "boolean", "integer", "bit_string", "octet_string", "null", "object_identifier", "utf8_string", "numeric_string", "printable_string", "ia5_string", "utc_time", "generalized_time", "visible_string", required)
• der_hex (string, required): min length 2; max length 512; pattern ^(?:[0-9a-f]{2})*$
• content_hex (string, required): max length 512; pattern ^(?:[0-9a-f]{2})*$
• boolean (boolean, optional)
• integer (string, optional): min length 1; max length 700; pattern ^(0|-?[1-9][0-9]*)$
• unused_bits (integer, optional): min 0; max 7
• payload_hex (string, optional): max length 512; pattern ^(?:[0-9a-f]{2})*$
• arcs (array of string, optional): min items 2; max items 256; each min length 1; each max length 600; each pattern ^(0|[1-9][0-9]*)$
• dotted (string, optional): min length 3; max length 2048
• text (string, optional): max length 256

Limits

• max der bytes: 256

Example

Request input:

{
  "der_hex": "0500"
}

Response:

{
  "result": {
    "tag": 5,
    "type_name": "null",
    "der_hex": "0500",
    "content_hex": ""
  }
}

How to call it

MCP

Connect https://computefirst.net/mcp (setup), then call execute with:

{
  "id": "asn1-der-primitive-decode",
  "version": "1.0.0",
  "input": {
    "der_hex": "0500"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/asn1-der-primitive-decode/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"der_hex":"0500"}'

The machine-readable contract is at /v1/tools/asn1-der-primitive-decode/versions/1.0.0.

CLI

node cli.mjs run asn1-der-primitive-decode 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Asn1 der primitive encode: Encode one universal DER primitive from typed fields into lowercase hex.
• Asn1 der parse: Parse one ASN.1 DER value into a flat schema-free TLV node list.
• Asn1 der encode tree: Encode a schema-free ASN.1 node list as one canonical DER value.
• Asn1 der node extract: Extract one DER node by a numeric path, with header, content, and child paths.
• Toml10 parse: Parse TOML 1.0 into typed nodes with exact int64, floats, and datetimes.
• Xpath10 evaluate: Evaluate an XPath 1.0 value expression and return its type with an exact string, number, or boolean token.