Multisig

Learn how to generate, sign and broadcast a transaction using the keyring multisig.

A multisig account is an Evmos account with a special key that can require more than one signature to sign transactions. This can be useful for increasing the security of the account or for requiring the consent of multiple parties to make transactions. Multisig accounts can be created by specifying:

• threshold number of signatures required
• the public keys involved in signing

To sign with a multisig account, the transaction must be signed individually by the different keys specified for the account. Then, the signatures will be combined into a multi-signature which can be used to sign the transaction. If fewer than the threshold number of signatures needed are present, the resultant multi-signature is considered invalid.

Generate a Multisig key

evmosd keys add --multisig=name1,name2,name3[...] --multisig-threshold=K new_key_name

K is the minimum number of private keys that must have signed the transactions that carry the public key's address as signer.

The --multisig flag must contain the name of public keys that will be combined into a public key that will be generated and stored as new_key_name in the local database. All names supplied through --multisig must already exist in the local database.

Unless the flag --nosort is set, the order in which the keys are supplied on the command line does not matter, i.e. the following commands generate two identical keys:

evmosd keys add --multisig=p1,p2,p3 --multisig-threshold=2 multisig_address
evmosd keys add --multisig=p2,p3,p1 --multisig-threshold=2 multisig_address

Multisig addresses can also be generated on-the-fly and printed through the which command:

evmosd keys show --multisig-threshold=K name1 name2 name3 [...]

Signing a transaction

Step 1: Create the multisig key

Let's assume that you have test1 and test2 want to make a multisig account with test3.

First import the public keys of test3 into your keyring.

evmosd keys add \
    test3 \
    --pubkey=evmospub1addwnpepqgcxazmq6wgt2j4rdfumsfwla0zfk8e5sws3p3zg5dkm9007hmfysxas0u2

Generate the multisig key with 2/3 threshold.

evmosd keys add \
    multi \
    --multisig=test1,test2,test3 \
    --multisig-threshold=2

You can see its address and details:

evmosd keys show multi

- name: multi
  type: multi
  address: evmos1e0fx0q9meawrcq7fmma9x60gk35lpr4xk3884m
  pubkey: evmospub1ytql0csgqgfzd666axrjzq3mxw59ys6yqcd3ydjvhgs0uzs6kdk5fp4t73gmkl8t6y02yfq7tvfzd666axrjzq3sd69kp5usk492x6nehqjal67ynv0nfqapzrzy3gmdk27la0kjfqfzd666axrjzq6utqt639ka2j3xkncgk65dup06t297ccljmxhvhu3rmk92u3afjuyz9dg9
  mnemonic: ""
  threshold: 0
  pubkeys: []

Let's add 10 EVMOS to the multisig wallet:

evmosd tx bank send \
    test1 \
    evmos1e0fx0q9meawrcq7fmma9x60gk35lpr4xk3884m \
    10000000000000000000aevmos \
    --chain-id=evmos_9000-4 \
    --gas=auto \
    --fees=1000000aevmos \
    --broadcast-mode=block

Step 2: Create the multisig transaction

We want to send 5 EVMOS from our multisig account to evmos1rgjxswhuxhcrhmyxlval0qa70vxwvqn2e0srft.

evmosd tx bank send \
    evmos1rgjxswhuxhcrhmyxlval0qa70vxwvqn2e0srft \
    evmos157g6rn6t6k5rl0dl57zha2wx72t633axqyvvwq \
    5000000000000000000aevmos \
    --gas=200000 \
    --fees=1000000aevmos \
    --chain-id=evmos_9000-4 \
    --generate-only > unsignedTx.json

The file unsignedTx.json contains the unsigned transaction encoded in JSON.

{
  "body": {
    "messages": [
      {
        "@type": "/cosmos.bank.v1beta1.MsgSend",
        "from_address": "evmos1rgjxswhuxhcrhmyxlval0qa70vxwvqn2e0srft",
        "to_address": "evmos157g6rn6t6k5rl0dl57zha2wx72t633axqyvvwq",
        "amount": [
          {
            "denom": "aevmos",
            "amount": "5000000000000000000"
          }
        ]
      }
    ],
    "memo": "",
    "timeout_height": "0",
    "extension_options": [],
    "non_critical_extension_options": []
  },
  "auth_info": {
    "signer_infos": [],
    "fee": {
      "amount": [
        {
          "denom": "aevmos",
          "amount": "1000000"
        }
      ],
      "gas_limit": "200000",
      "payer": "",
      "granter": ""
    }
  },
  "signatures": []
}

Step 3: Sign individually

Sign with test1 and test2 and create individual signatures.

evmosd tx sign \
    unsignedTx.json \
    --multisig=evmos1e0fx0q9meawrcq7fmma9x60gk35lpr4xk3884m \
    --from=test1 \
    --output-document=test1sig.json \
    --chain-id=evmos_9000-4

evmosd tx sign \
    unsignedTx.json \
    --multisig=evmos1e0fx0q9meawrcq7fmma9x60gk35lpr4xk3884m \
    --from=test2 \
    --output-document=test2sig.json \
    --chain-id=evmos_9000-4

Step 4: Create multisignature

Combine signatures to sign transaction.

evmosd tx multisign \
    unsignedTx.json \
    multi \
    test1sig.json test2sig.json \
    --output-document=signedTx.json \
    --chain-id=evmos_9000-4

The TX is now signed:

{
  "body": {
    "messages": [
      {
        "@type": "/cosmos.bank.v1beta1.MsgSend",
        "from_address": "evmos1rgjxswhuxhcrhmyxlval0qa70vxwvqn2e0srft",
        "to_address": "evmos157g6rn6t6k5rl0dl57zha2wx72t633axqyvvwq",
        "amount": [
          {
            "denom": "aevmos",
            "amount": "5000000000000000000"
          }
        ]
      }
    ],
    "memo": "",
    "timeout_height": "0",
    "extension_options": [],
    "non_critical_extension_options": []
  },
  "auth_info": {
    "signer_infos": [
      {
        "public_key": {
          "@type": "/cosmos.crypto.multisig.LegacyAminoPubKey",
          "threshold": 2,
          "public_keys": [
            {
              "@type": "/cosmos.crypto.secp256k1.PubKey",
              "key": "ApCzSG8k7Tr4aM6e4OJRExN7cNtvH21L9azbh+uRrvt4"
            },
            {
              "@type": "/cosmos.crypto.secp256k1.PubKey",
              "key": "Ah91erz8ChNanqLe9ea948rvAiXMCRlR5Ka7EE/c0xUK"
            },
            {
              "@type": "/cosmos.crypto.secp256k1.PubKey",
              "key": "A0OjtIUCFJM3AobJ9HJTWKP9RZV2+WPcwVjLgsAidrZ/"
            }
          ]
        },
        "mode_info": {
          "multi": {
            "bitarray": {
              "extra_bits_stored": 3,
              "elems": "wA=="
            },
            "mode_infos": [
              {
                "single": {
                  "mode": "SIGN_MODE_LEGACY_AMINO_JSON"
                }
              },
              {
                "single": {
                  "mode": "SIGN_MODE_LEGACY_AMINO_JSON"
                }
              }
            ]
          }
        },
        "sequence": "1"
      }
    ],
    "fee": {
      "amount": [
        {
          "denom": "aevmos",
          "amount": "1000000"
        }
      ],
      "gas_limit": "200000",
      "payer": "",
      "granter": ""
    }
  },
  "signatures": [
    "CkCEeIbeGc+I1ipZuhp/0KhVNnWAv2tTlvgo5x61lzk1KHmLPV38m/YFurrFt5cm5+fqIXrn+FlOjrJuzBhw8ogYCkCawm9mpXsBHk0CFsE5618fVnvScEkfrzW0c2jCcjqV8EPuj3ut74UWzZyQkwtJGxUWtro9EgnGsB7Di1Gzizst"
  ]
}

Step 5: Broadcast transaction

evmosd tx broadcast signedTx.json \
    --chain-id=evmos_9000-4 \
    --broadcast-mode=block