It was the best of times, it was the worst of times… it was Stellar times.

Operations on Stellar are grouped into one of three different security levels, called thresholds: Low, Medium, and High. When setting up a Stellar account to use multisig, you are given the option to set values for each of these threshold levels, as well as weights for each of the signers on the account. In order for a transaction to be considered valid, the weights of the signatures on the transaction that correspond to each operation’s source account must sum up to the value you set for the threshold for that operation type.

Whew, that’s a lot of words, but what does it really mean? Let’s look at an example.

Let’s say a Stellar account has the following threshold levels:

Low: 1

Medium: 2

High: 3

And the following signers and weights:

Master Weight: 2

Signer 1 Weight: 1

Signer 2 Weight: 1

That means that in order to perform a Medium threshold operation, like sending someone XLM, you must reach a total weight of 2, so either the account owner needs to sign the transaction or both Signers 1 and 2 need to sign it (so their combined weight equals 2).

For a High threshold transaction you’d need a combined weight of 3, so the account owner and one of the signers would need to sign it. Finally, a Low threshold operation only needs weight 1, so any of the signers on the account could sign in.