baddress

baddress: populate a DynamoDB with bad addresses

We want a service where anyone anywhere can securely check an address to see if it is known to be compromised, or otherwise known to be a bad idea to use. This is a key-value-store problem, easily solved by DynamoDB, AWS's KVSaaS.

The point of baddress is to populate the DB. It can generate a large quantity of bad addresses automatically, or manually insert known-bad addresses.

This service depends on the AWS SDK, which can populate its keys and secrets from the environment or certain configuration files.

Accessing the Data

Low Level

This database is stored in DynamoDB. At a low level, this can be accessed via signed HTTP(S) POST requests. An overview of that API is here and a reference is here.

Mid Level

At a medium level, Amazon provides SDKs in multiple languages which take care of much of the gruntwork of correctly forming these requests. At that level, the important data for connections is:

Region: us-east-1

Table name: bad-addresses

A positive existence query using the CLI:

$ aws dynamodb get-item --table-name bad-addresses --key '{"address":{"S":"ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc7"}}'
{
    "Item": {
        "derivation-path": {
            "S": "/44'/20036'/100/5"
        },
        "reason": {
            "S": "derives from 12-word phrase with identical words: hockey"
        },
        "address": {
            "S": "ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc7"
        }
    }
}

A negative existence query using the CLI produces no output:

$ aws dynamodb get-item --table-name bad-addresses --key '{"address":{"S":"ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc8"}}'

High Level

There is a public lambda function which will return appropriate existence information without authentication requirements:

$ http post https://dh3bwcunu1.execute-api.us-east-1.amazonaws.com/default/address-check address=ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc7 --print=HBhb
POST /default/address-check HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 63
Content-Type: application/json
Host: dh3bwcunu1.execute-api.us-east-1.amazonaws.com
User-Agent: HTTPie/0.9.8

{
    "address": "ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc7"
}

HTTP/1.1 200 OK
Connection: keep-alive
Content-Length: 199
Content-Type: application/json
Date: Wed, 21 Aug 2019 09:47:30 GMT
X-Amzn-Trace-Id: Root=1-5d5d1332-8aa0067c063f67b01ee2d82e;Sampled=0
x-amz-apigw-id: ew_v1G5QIAMFnbA=
x-amzn-RequestId: b10b6326-c3f8-11e9-abbb-e374a253dd72

{
    "data": {
        "address": "ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc7",
        "derivation-path": "/44'/20036'/100/5",
        "reason": "derives from 12-word phrase with identical words: hockey"
    },
    "exists": true
}

$ http post https://dh3bwcunu1.execute-api.us-east-1.amazonaws.com/default/address-check address=ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc8 --print=HBhb
POST /default/address-check HTTP/1.1
Accept: application/json, */*
Accept-Encoding: gzip, deflate
Connection: keep-alive
Content-Length: 63
Content-Type: application/json
Host: dh3bwcunu1.execute-api.us-east-1.amazonaws.com
User-Agent: HTTPie/0.9.8

{
    "address": "ndaa59e7jxegzrjeeyiw3374spk7b93g3x7eb4kkm34tefc8"
}

HTTP/1.1 200 OK
Connection: keep-alive
Content-Length: 17
Content-Type: application/json
Date: Wed, 21 Aug 2019 09:47:40 GMT
X-Amzn-Trace-Id: Root=1-5d5d133c-f7ef3af46f1c6c24792000c8;Sampled=0
x-amz-apigw-id: ew_xaFscIAMF_GA=
x-amzn-RequestId: b71086d8-c3f8-11e9-9edb-11b522a6e291

{
    "exists": false
}