# Multihash digest verify

`multihash-digest-verify` · version 1.0.0 · Hashing & signatures · free, no key needed

Verify exact digest bytes and optional algorithm against a canonical multihash.

**Use when you need to: verify digest matches multihash · detect multihash algorithm confusion · compare digest bytes with multihash.**

## Decide before calling

Read the [versioned contract](/v1/tools/multihash-digest-verify/versions/1.0.0) and the supported scope below. Reuse `multihash-digest-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 `multihash-digest-verify@1.0.0` for verify digest matches multihash. 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 digest matches multihash
- detect multihash algorithm confusion
- compare digest bytes with multihash
- check multihash digest equality
- validate expected multihash algorithm
- audit content address digest envelope

## Not supported

- hashing message content
- signature or identity verification

## Behavior

- A well-typed mismatch, including an explicit different algorithm, returns valid false.
- Malformed or noncanonical multihashes throw invalid_input.
- Verification is security-sensitive; callers must separately enforce an acceptable algorithm policy.

## Input

- `multihash` (string, required): max length 136; pattern `^(?:[0-9a-f]{2})*$`
- `digest` (string, required): max length 128; pattern `^(?:[0-9a-f]{2})*$`
- `algorithm` (one of "sha2-256", "sha2-512", "sha3-512", "sha3-384", "sha3-256", "sha3-224", "blake3", "blake2b-256", "blake2b-512", "blake2s-256", optional)

## Output

- `valid` (boolean, required)
- `algorithm` (string, required)
- `code` (integer, required): min 0
- `digest_size` (integer, required): min 0; max 64
- `standard` (string, required)
- `reference` (string, required)
- `data_version` (string, required)

## Limits

- max multihash bytes: 68
- max digest bytes: 64

## Example

Request input:

```json
{
  "multihash": "12200000000000000000000000000000000000000000000000000000000000000000",
  "digest": "0000000000000000000000000000000000000000000000000000000000000000"
}
```

Response:

```json
{
  "result": {
    "valid": true,
    "algorithm": "sha2-256",
    "code": 18,
    "digest_size": 32,
    "standard": "Multiformats Multihash specification",
    "reference": "multihash = varint(code) || varint(size) || digest; unsigned LEB128 must be minimally encoded",
    "data_version": "multicodec-2026-10-24"
  }
}
```

## How to call it

### MCP

Connect `https://computefirst.net/mcp` ([setup](/docs#connect)), then call `execute` with:

```json
{
  "id": "multihash-digest-verify",
  "version": "1.0.0",
  "input": {
    "multihash": "12200000000000000000000000000000000000000000000000000000000000000000",
    "digest": "0000000000000000000000000000000000000000000000000000000000000000"
  }
}
```

### HTTP (no key)

```sh
curl -X POST https://computefirst.net/v1/tools/multihash-digest-verify/versions/1.0.0/execute \
  -H "Content-Type: application/json" \
  -d '{"multihash":"12200000000000000000000000000000000000000000000000000000000000000000","digest":"0000000000000000000000000000000000000000000000000000000000000000"}'
```

The machine-readable contract is at [/v1/tools/multihash-digest-verify/versions/1.0.0](/v1/tools/multihash-digest-verify/versions/1.0.0).

### CLI

```sh
node cli.mjs run multihash-digest-verify 1.0.0 --input input.json --base-url https://computefirst.net
```

Get the client at [/clients/cli/](/clients/cli/).

## Related tools

- [Oci descriptor verify](/tools/oci-descriptor-verify): Verify supplied bytes against an OCI descriptor digest and size.
- [Multihash decode](/tools/multihash-decode): Strictly decode a canonical bounded hexadecimal multihash.
- [Xxh3 vector suite verify](/tools/xxh3-vector-suite-verify): Verify a bounded public suite of expected XXH3-64 and XXH3-128 known-answer vectors.
- [Adler-32 chunks verify](/tools/adler32-chunks-verify): Verify that an ordered chunk list and a whole message have identical Adler-32 checksums.
- [Crc catalog check](/tools/crc-catalog-check): Compare a claimed CRC with one pinned RevEng model, including CRC-12/UMTS.
- [Hash digest verify](/tools/hash-digest-verify): Recompute a fixed-length digest over encoded input bytes and compare it to an expected digest given in any encoding.