Xxh3 128 compute

xxh3-128-compute · version 1.0.0 · Hashing & signatures · free, no key needed

Compute the bit-exact XXH3 128-bit hash with a uint64 seed or public 192-byte custom secret.

Use when you need to: compute XXH3 128-bit hash · hash bytes with seeded XXH3-128 · hash data with a public custom XXH3 secret.

Decide before calling

Read the versioned contract and the supported scope below. Reuse xxh3-128-compute@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 xxh3-128-compute@1.0.0 for compute XXH3 128-bit hash. 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

• compute XXH3 128-bit hash
• hash bytes with seeded XXH3-128
• hash data with a public custom XXH3 secret
• reproduce an XXH3-128 content identifier
• calculate a 128-bit XXH3 checksum
• inspect canonical XXH3 hash lanes

Not supported

• cryptographic hashing or signatures
• streaming state or secret generation

Behavior

• Implements every XXH3 length path using xxHash v0.8.3 scalar semantics; seed and secret_hex are mutually exclusive.
• hex is high64 then low64, while the two named lanes remove byte-order ambiguity.
• Disclaimer: format transform only; provides no confidentiality, integrity, or authenticity.

Input

• text (string, required): max length 262144
• input_encoding (one of "utf8", "hex", "base64", "base64url", optional): default "utf8"
• seed (string, optional): pattern ^(0|[1-9][0-9]{0,20})$; default "0"
• secret_hex (string, optional): pattern ^[0-9a-f]{384}$

Output

• algorithm (one of "xxh3-128", required)
• hex (string, required): pattern ^[0-9a-f]{32}$
• low64_hex (string, required): pattern ^[0-9a-f]{16}$
• high64_hex (string, required): pattern ^[0-9a-f]{16}$
• standard (string, required)
• reference (string, required)

Limits

• max input bytes: 65536
• secret bytes: 192

Example

Request input:

{
  "text": ""
}

Response:

{
  "result": {
    "algorithm": "xxh3-128",
    "hex": "99aa06d3014798d86001c324468d497f",
    "low64_hex": "6001c324468d497f",
    "high64_hex": "99aa06d3014798d8",
    "standard": "xxHash specification and upstream xxHash v0.8.3 sanity vectors",
    "reference": "Cyan4973/xxHash v0.8.3"
  }
}

How to call it

MCP

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

{
  "id": "xxh3-128-compute",
  "version": "1.0.0",
  "input": {
    "text": ""
  }
}

HTTP (no key)

curl -X POST https://computefirst.net/v1/tools/xxh3-128-compute/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"text":""}'

The machine-readable contract is at /v1/tools/xxh3-128-compute/versions/1.0.0.

CLI

node cli.mjs run xxh3-128-compute 1.0.0 --input input.json --base-url https://computefirst.net

Get the client at /clients/cli/.

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