Sign a transaction with EDDSA and Baby Jubjub

This tutorial walks you through signing an Ethereum transaction with Quorum Key Manager (QKM) using the EDDSA signing algorithm and Baby Jubjub elliptic curve (also referred to as the BN254 twisted Edwards curve).

Prerequisites

Quorum Key Manager installed
curl command line
HashiCorp Vault service running
HashiCorp Vault - Orchestrate Plugin loaded in HashiCorp Vault service

Steps

In the QKM manifest file, specify an Ethereum store to allocate your Ethereum wallets, and the RPC node to proxy your calls using QKM.

Example manifest file
- kind: HashicorpKeys
  name: hashicorp-keys
  specs:
    mountPoint: "{ENGINE_MOUNT_POINT}"
    address: "{HASHICORP_VAULT_URL}"
    tokenPath: "{VAULT_TOKEN_PATH}"
    namespace: "{KEYS_NAMESPACE}"

- kind: Node
  name: besu-node
  specs:
    rpc:
      addr: http://besu-node:8545

Start QKM with the manifest file by using the --manifest-path option:
```
key-manager run --manifest-path=<PATH-TO-MANIFEST-FILE>
```

Create an Ethereum account using EDDSA and Baby Jubjub:

curl HTTP request
JSON result

curl --request POST 'http://localhost:8080/stores/hashicorp-keys/keys/bn254-key' --header 'Content-Type: application/json' --data-raw '{"curve": "babyjubjub", "signingAlgorithm": "eddsa"}'

{
  "id": "bn254-key",
  "publicKey": "Cjix/fS3WdqKGKabagBNYwcClan5aImoFpnjSF0cqJs=",
  "curve": "babyjubjub",
  "signingAlgorithm": "eddsa",
  "disabled": false,
  "createdAt": "2021-09-09T11:18:51.5877561Z",
  "updatedAt": "2021-09-09T11:18:51.5877561Z"
}

Sign a payload using the created key pair:
- Generate base64 message to sign
echo -n "my signed message" | base64

Base64 encoding result

```bash
bXkgc2lnbmVkIG1lc3NhZ2U=
```

curl HTTP request

```bash
curl --request POST 'http://localhost:8080/stores/hashicorp-keys/keys/bn254-key/sign' --header 'Content-Type: application/json' --data-raw '{"data": "bXkgc2lnbmVkIG1lc3NhZ2U="}'
```

JSON result

```json
tjThYhKSFSKKvsR8Pji6EJ+FYAcf8TNUdAQnM7MSwZEEaPvFhpr1SuGpX5uOcYUrb3pBA8cLk8xcbKtvZ56qWA==
```

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Verify your message:

curl HTTP request

curl --request POST 'http://localhost:8080/stores/hashicorp-keys/keys/verify-signature' --header 'Content-Type: application/json' --data-raw '{"curve": "babyjubjub", "signingAlgorithm": "eddsa", "data": "bXkgc2lnbmVkIG1lc3NhZ2U=", "publicKey": "yhUiySkg/cKbiN8soKZ5YO0GXHqzx8iycnABzYMPE5A=", "signature": "tjThYhKSFSKKvsR8Pji6EJ+FYAcf8TNUdAQnM7MSwZEEaPvFhpr1SuGpX5uOcYUrb3pBA8cLk8xcbKtvZ56qWA=="}'