Pem label validate

pem-label-validate · version 1.0.0 · Encoding & checksums · free, no key needed

Check a PEM label against the RFC 7468 label grammar, without reading a payload.

Use when you need to: validate a pem label · check rfc 7468 label grammar · is this begin-end label well formed.

Decide before calling

Read the versioned contract and the supported scope below. Reuse pem-label-validate@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 pem-label-validate@1.0.0 for validate a pem label. 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

• validate a pem label
• check rfc 7468 label grammar
• is this begin-end label well formed
• pem label character rules
• allow a space inside a pem label
• reject consecutive hyphens in a pem label

Not supported

• decide whether the label matches the payload type
• case-fold a label to an uppercase registered name
• map a label onto an asn.1 module

Behavior

• The label matches RFC 7468 section 3: empty, or one labelchar followed by groups of an optional single SP or hyphen and another labelchar. labelchar is printable US-ASCII except SP (0x20) and hyphen (0x2D). Case is significant and is not folded.
• The first failing position wins: a separator at either end is edge_separator, two separators in a row are consecutive_separator, and any other rejected character is bad_character. A grammar failure of a label within the byte bound returns {valid:false, reason} and does not throw.
• Registered labels in section 4 (CERTIFICATE, X509 CRL, ENCRYPTED PRIVATE KEY, and the rest) are ordinary strings under this grammar. "X.509 CERTIFICATE" is grammatical and is not equated with "CERTIFICATE".
• The byte limit of 64 is checked before the grammar. A label of 65 bytes is limit_exceeded, not a false result, including when the extra characters would also fail the grammar. RFC 7468 does not define this bound; the output schema uses the same 64.
• A lone surrogate throws invalid_input. Ordinary non-ASCII inside the byte bound is bad_character. This tool does not look at a PEM body and makes no certificate or key claim.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• label (string, required): min length 0; max length 64

Output

• valid (boolean, required)
• length (integer, optional): min 0; max 64
• reason (one of "bad_character", "consecutive_separator", "edge_separator", optional)

Limits

• max label bytes: 64
• max output bytes: 160

Example

Request input:

{
  "label": "CERTIFICATE"
}

Response:

{
  "result": {
    "valid": true,
    "length": 11
  }
}

How to call it

MCP

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

{
  "id": "pem-label-validate",
  "version": "1.0.0",
  "input": {
    "label": "CERTIFICATE"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/pem-label-validate/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"label":"CERTIFICATE"}'

The machine-readable contract is at /v1/tools/pem-label-validate/versions/1.0.0.

CLI

node cli.mjs run pem-label-validate 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Pem envelope validate: Check one RFC 7468 PEM envelope for labels, whitespace, and strict base64.
• Pem envelope format: Format a label and lowercase hex bytes as a canonical RFC 7468 PEM envelope.
• Pem envelope parse: Parse one RFC 7468 textual envelope into its label and lowercase hex bytes.
• Segwit address validate: Validate a native segwit address and report which Bech32 or Bech32m rule failed.
• Bech32 validate: Check Bech32 or Bech32m text and return a reason, without throwing when the checksum fails.
• Ct inclusion proof verify: Strictly verify an RFC 6962 v1 Merkle audit path.