Multi-signature accounts can be used to require that transactions require multiple public keys to sign before they are considered valid. This is done by first configuring your account’s threshold levels. Each operation has a threshold level of either low, medium, or high. You give each threshold level a number between 1-255 in your account. Then, for each key in your account, you assign it a weight (1-255, setting a 0 weight deletes the key). Any transaction must be signed with enough keys to meet the threshold.
For example, let’s say you set your threshold levels; low = 1, medium = 2, high = 3. You want to send a payment operation, which is a medium threshold operation. Your master key has weight 1. Additionally, you have a secondary key associated with your account which has a weight of 1. Now, the transaction you submit for this payment must include both signatures of your master key and secondary key since their combined weight is 2 which is enough to authorize the payment operation.
In this example, we will:
Add a second signer to the account
Set our account’s masterkey weight and threshold levels
Create a multi signature transaction that sends a payment
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from stellar_sdk import Server, TransactionBuilder, Signer, Network, Keypair server = Server(horizon_url="https://horizon-testnet.stellar.org") root_keypair = Keypair.from_secret("SA6XHAH4GNLRWWWF6TEVEWNS44CBNFAJWHWOPZCVZOUXSQA7BOYN7XHC") root_account = server.load_account(account_id=root_keypair.public_key) secondary_keypair = Keypair.from_secret("SAMZUAAPLRUH62HH3XE7NVD6ZSMTWPWGM6DS4X47HLVRHEBKP4U2H5E7") secondary_signer = Signer.ed25519_public_key(account_id=secondary_keypair.public_key, weight=1) transaction = TransactionBuilder( source_account=root_account, network_passphrase=Network.TESTNET_NETWORK_PASSPHRASE, base_fee=100) \ .append_set_options_op( master_weight=1, # set master key weight low_threshold=1, med_threshold=2, # a payment is medium threshold high_threshold=2, # make sure to have enough weight to add up to the high threshold! signer=secondary_signer) \ .set_timeout(30) \ .build() # only need to sign with the root signer as the 2nd signer won't # be added to the account till after this transaction completes transaction.sign(root_keypair) response = server.submit_transaction(transaction) print(response) # now create a payment with the account that has two signers destination = "GBA5SMM5OYAOOPL6R773MV7O3CCLUDVLCWHIVVL3W4XTD3DA5FJ4JSEZ" transaction = TransactionBuilder( source_account=root_account, network_passphrase=Network.TESTNET_NETWORK_PASSPHRASE, base_fee=100) \ .append_payment_op( destination=destination, amount="2000", asset_code="XLM") \ .set_timeout(30) \ .build() # now we need to sign the transaction with both the root and the secondary_keypair transaction.sign(root_keypair) transaction.sign(secondary_keypair) response = server.submit_transaction(transaction) print(response)