# ShieldAPI Password Range Check

> ShieldAPI Password Range Check is a paid API for AI agents from shield.vainplex.dev, paid per call via x402, $0.001/call, status unknown (last checked 2026-09-15).

Checks whether a password has appeared in known data breaches using k-anonymity (SHA-1 prefix lookup), without exposing the full password hash

## Facts

- Endpoint: GET https://shield.vainplex.dev/api/cdp/check-password-range
- Price: $0.001/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-15
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/shield-vainplex-dev-5f12fb3c
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_DYPCmwAXjIjH62J0CcZ1M

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability shield-vainplex-dev-5f12fb3c
```

Example prompt: Can you check if the password 'hunter2' has ever appeared in a known data breach? Use the first 5 characters of its SHA-1 hash — that's '5BAA6' — to do the anonymized range lookup so the full hash never gets sent.

## When to prefer this

Use this endpoint when you need to check whether a password has been exposed in known data breaches while preserving user privacy via k-anonymity (only the first 5 characters of the SHA-1 hash are sent). Prefer this over full-hash lookups when privacy is critical. It mirrors the HaveIBeenPwned range API pattern and is ideal for real-time password validation during registration or login flows.

## Known failure modes

- Missing or invalid 'prefix' query parameter — returns 400 or error response
- Prefix not exactly 5 hex characters — malformed request
- Network timeout or service unavailability — returns 5xx
- Payment failure (x402) — returns 402 if USDC payment not processed

## How this service works

ShieldAPI - x402 security preflight before agents accept or store credential material

## Output

Returns a list of SHA-1 hash suffixes and their breach occurrence counts for all hashes sharing the given 5-character prefix. The agent can match the remaining hash suffix locally to determine if a specific password has been compromised and how many times it appeared in breached datasets.

## Example request

```json
{
 "input": {
  "type": "http",
  "method": "GET",
  "queryParams": {
   "prefix": "5BAA61"
  }
 },
 "output": {
  "type": "string"
 }
}
```

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "$schema": "https://json-schema.org/draft/2020-12/schema",
 "required": [
  "input"
 ],
 "properties": {
  "input": {
   "type": "object",
   "required": [
    "type",
    "method"
   ],
   "properties": {
    "type": {
     "type": "string",
     "const": "http"
    },
    "method": {
     "enum": [
      "GET"
     ],
     "type": "string"
    },
    "queryParams": {
     "type": "object",
     "required": [
      "prefix"
     ],
     "properties": {
      "prefix": {
       "type": "string",
       "description": "First 5 characters of SHA-1 hash"
      }
     }
    }
   },
   "additionalProperties": false
  },
  "output": {
   "type": "object",
   "required": [
    "type"
   ],
   "properties": {
    "type": {
     "type": "string"
    },
    "example": {
     "type": "object"
    }
   }
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/shield-vainplex-dev-5f12fb3c/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from shield.vainplex.dev](https://www.zero.xyz/host/shield.vainplex.dev/llms.txt)