Encrypt transactions for `x/pep` module

This tutorial explains how to encrypt your transaction for x/pep module using encrypter that built-in fairyringd. Ensure you installed the fairyring binary prior to following the instructions below.

For confidential stablecoin transfers, we use Homomorphic Encryption (HE). This application does not require special integrations or developer setup. This tutorial is focused on Simple IBE-MPC encrypted transactions with Target Blobck Height as the condition for automatic decryption and execution**

Encrypt your transaction

Getting the public key for encryption

PUBKEY=$(fairyringd query pep show-active-pub-key | jq -r '.active_pubkey.public_key')

Create the signed transaction. We'll use a bank send transaction in this example.

fairyringd tx bank send [FROM_ADDRESS] [TO_ADDRESS] [AMOUNT] --from [YOUR_ACCOUNT_NAME] --gas-prices 1ufairy --generate-only -o json -y > unsigned.json

[FROM_ADDRESS] is the address you are using to send the token.
[TO_ADDRESS] is the recipient address.
[AMOUNT] is the amount you would like to send.
[YOUR_ACCOUNT_NAME] is the account name of your [FROM_ADDRESS].
--gas-prices is the gas price you are paying.
--generate-only means you only generate the unsigned transaction.
-o json means to output the unsigned transaction in json format.
> unsigned.json means outputs the unsigned transaction to a file named unsigned.json.

Example:

fairyringd tx bank send fairy18hl5c9xn5dze2g50uaw0l2mr02ew57zkynp0td fairy1qnk2n4nlkpw9xfqntladh74w6ujtulwnsgww3g 100ufairy --from alice --gas-prices 1ufairy --generate-only -o json -y > unsigned.json

This corresponds to a transaction that sends 100ufairy from alice (fairy18hl5c9xn5dze2g50uaw0l2mr02ew57zkynp0td) to fairy1qnk2n4nlkpw9xfqntladh74w6ujtulwnsgww3g.

The unsigned.json looks something like this:

{
 "body": {
  "messages": [
   {
    "@type": "/cosmos.bank.v1beta1.MsgSend",
    "from_address": "fairy18hl5c9xn5dze2g50uaw0l2mr02ew57zkynp0td",
    "to_address": "fairy1qnk2n4nlkpw9xfqntladh74w6ujtulwnsgww3g",
    "amount": [{ "denom": "ufairy", "amount": "100" }]
   }
  ],
  "memo": "",
  "timeout_height": "0",
  "extension_options": [],
  "non_critical_extension_options": []
 },
 "auth_info": {
  "signer_infos": [],
  "fee": {
   "amount": [{ "denom": "ufairy", "amount": "200000" }],
   "gas_limit": "200000",
   "payer": "",
   "granter": ""
  },
  "tip": null
 },
 "signatures": []
}

Signing the transaction

SIGNED=$(fairyringd tx sign unsigned.json --from [ACCOUNT_NAME] --offline \
--account-number $(fairyringd query account $(fairyringd keys show [ACCOUNT_NAME] -a) -o json | jq -r '.account_number') \
--sequence $(fairyringd query pep show-pep-nonce $(fairyringd keys show [ACCOUNT_NAME] -a) -o json | jq -r '.pepNonce.nonce'))

[ACCOUNT_NAME] replace all instances to the account name you are using to sign the transaction.
--offline means that you are signing your transaction offline with the provided account number & sequence instead of fetching it from the chain.
--account-number is your account number, the command above will fetch it for you automatically.
--sequence is the pep nonce of your address, the command above will fetch it for you automatically.

Example:

SIGNED=$(fairyringd tx sign unsigned.json --from alice --offline \
--account-number $(fairyringd query account $(fairyringd keys show alice -a) -o json | jq -r '.account_number') \
--sequence $(fairyringd query pep show-pep-nonce $(fairyringd keys show alice -a) -o json | jq -r '.pepNonce.nonce'))

The signed transaction looks like this:

{
 "body": {
  "messages": [
   {
    "@type": "/cosmos.bank.v1beta1.MsgSend",
    "from_address": "fairy18hl5c9xn5dze2g50uaw0l2mr02ew57zkynp0td",
    "to_address": "fairy1qnk2n4nlkpw9xfqntladh74w6ujtulwnsgww3g",
    "amount": [{ "denom": "ufairy", "amount": "100" }]
   }
  ],
  "memo": "",
  "timeout_height": "0",
  "extension_options": [],
  "non_critical_extension_options": []
 },
 "auth_info": {
  "signer_infos": [
   {
    "public_key": {
     "@type": "/cosmos.crypto.secp256k1.PubKey",
     "key": "A3wiGqD+PZYB+hgRmWbD3Sugv2Ofw3G7rFjT0PJ7SBIZ"
    },
    "mode_info": { "single": { "mode": "SIGN_MODE_DIRECT" } },
    "sequence": "3"
   }
  ],
  "fee": {
   "amount": [{ "denom": "ufairy", "amount": "200000" }],
   "gas_limit": "200000",
   "payer": "",
   "granter": ""
  },
  "tip": null
 },
 "signatures": [
  "vmPWsuAsasg...10Ad2QafEByg2q0zug=="
 ]
}

You can check your signed transaction with the following command:

echo $SIGNED | jq

Encrypting the transaction

ENCRYPTED=$(fairyringd encrypt [TARGET_HEIGHT / REQ-ID] $PUBKEY $SIGNED)

[TARGET_HEIGHT / REQ-ID] is the target execution height of your transaction, or if you are encrypting a general tx, it is the request id / identity. It will also be used when you submit the encrypted transaction.
$PUBKEY is the public key (encryption key) you got from Step 1.
$SIGNED is the signed transaction from Step 3.

Check the encrypted transaction by:

echo $ENCRYPTED

Submit the encrypted transaction

fairyringd tx pep submit-encrypted-tx $ENCRYPTED [TARGET_HEIGHT] --from [ACCOUNT_NAME] --gas-prices 1ufairy -y

$ENCRYPTED is the hex encoded encrypted tx from encrypter
[TARGET_HEIGHT] is the target execution height of your transaction. This should be the same as the [TARGET_HEIGHT] used when encrypting the transaction using encrypter
[ACCOUNT_NAME] is the account you would like to send the transaction from. This should be the same as the account you used to sign the transaction.

If you are submitting a general encrypted transaction:

fairyringd tx pep submit-general-encrypted-tx $ENCRYPTED [REQ-ID] --from [ACCOUNT_NAME] --gas-prices 1ufairy -y

$ENCRYPTED is the hex encoded encrypted tx from encrypter
[REQ-ID] is the request id / identity used in encryption. This should be the same as the [REQ-ID] used when encrypting the transaction using encrypter
[ACCOUNT_NAME] is the account you would like to send the transaction from. This should be the same as the account you used to sign the transaction.

Encrypt your transaction​

Encrypt your transaction