Crc check value verify

crc-check-value-verify · version 1.0.0 · Hashing & signatures · free, no key needed

Recompute a pinned catalogue CRC of ASCII 123456789 and compare an observed check.

Use when you need to: verify the catalogue crc check of 123456789 · compare an observed check with the standard nine byte crc · recompute the published crc check field.

Decide before calling

Read the versioned contract and the supported scope below. Reuse crc-check-value-verify@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 crc-check-value-verify@1.0.0 for verify the catalogue crc check of 123456789. 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

• verify the catalogue crc check of 123456789
• compare an observed check with the standard nine byte crc
• recompute the published crc check field
• confirm an alias maps to the canonical crc check
• does this hex check match the pinned crc row
• standard ascii crc check comparison
• אימות ערך הביקורת מהקטלוג

Not supported

• verify a crc over caller-supplied message bytes
• decide which catalogue algorithm produced a frame
• treat a matching check value as proof of authenticity

Behavior

• name is a canonical catalogue name or an alias from the pinned CRC RevEng subset (data_version crc-reveng-catalogue-2026-10-21), compared case-sensitively with no trimming. An unknown name is unsupported_input.
• The recomputed check is the CRC of the nine ASCII bytes 123456789 under that row. It is calculated again on each call and compared with the pinned published check and with observed_check_hex.
• observed_check_hex is case-insensitive, has no 0x prefix, and must contain exactly width/4 hexadecimal digits. A well-formed check that differs is a successful result with the match booleans false, not an error.
• alias_used is true when name is not the canonical catalogue name. This tool does not accept a message, a parameter override, or a residue comparison.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• name (string, required): min length 1; max length 24
• observed_check_hex (string, required): min length 1; max length 16; pattern ^[0-9a-fA-F]*$

Output

• data_version (constant "crc-reveng-catalogue-2026-10-21", required)
• canonical_name (string, required): min length 1; max length 24
• supplied_name (string, required): min length 1; max length 24
• alias_used (boolean, required)
• width (one of 8, 16, 24, 32, 64, required)
• published_check_hex (string, required): min length 2; max length 16; pattern ^[0-9a-f]+$
• recomputed_check_hex (string, required): min length 2; max length 16; pattern ^[0-9a-f]+$
• observed_check_hex (string, required): min length 2; max length 16; pattern ^[0-9a-f]+$
• observed_matches_published (boolean, required)
• observed_matches_recomputed (boolean, required)
• published_matches_recomputed (boolean, required)

Limits

• max name bytes: 24
• max check hex chars: 16

Example

Request input:

{
  "name": "CRC-32/ISO-HDLC",
  "observed_check_hex": "CBF43926"
}

Response:

{
  "result": {
    "data_version": "crc-reveng-catalogue-2026-10-21",
    "canonical_name": "CRC-32/ISO-HDLC",
    "supplied_name": "CRC-32/ISO-HDLC",
    "alias_used": false,
    "width": 32,
    "published_check_hex": "cbf43926",
    "recomputed_check_hex": "cbf43926",
    "observed_check_hex": "cbf43926",
    "observed_matches_published": true,
    "observed_matches_recomputed": true,
    "published_matches_recomputed": true
  }
}

How to call it

MCP

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

{
  "id": "crc-check-value-verify",
  "version": "1.0.0",
  "input": {
    "name": "CRC-32/ISO-HDLC",
    "observed_check_hex": "CBF43926"
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/crc-check-value-verify/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"name":"CRC-32/ISO-HDLC","observed_check_hex":"CBF43926"}'

The machine-readable contract is at /v1/tools/crc-check-value-verify/versions/1.0.0.

CLI

node cli.mjs run crc-check-value-verify 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

Related tools

• Crc catalog check: Compare a claimed CRC with one pinned RevEng model, including CRC-12/UMTS.
• Hash digest verify: Recompute a fixed-length digest over encoded input bytes and compare it to an expected digest given in any encoding.
• Crc parameters validate: Validate a Rocksoft CRC parameter tuple against the pinned CRC RevEng catalogue.
• Crc catalog compute: Compute a pinned RevEng CRC of hex bytes, including crossed-endian CRC-12/UMTS.
• Crc catalog identify: Identify pinned CRC RevEng algorithms that match every explicit message and check sample.
• Crc catalog list: List the pinned RevEng CRC models with check values, residues, and reflection.