Author: Andrew Chow 2021-01-06 23:48:31
Published on: 2021-01-06T23:48:31+00:00
In an email conversation between Rusty Russell and Andrew, Rusty expresses his excitement towards the progress made in regards to a proposed new global field for PSBT (Partially Signed Bitcoin Transactions). The proposed field is named "PSBT_GLOBAL_UNDER_CONSTRUCTION" and its purpose is to indicate whether inputs and outputs can be added to the PSBT. This flag may be set to True when inputs and outputs are being updated, signed, and finalized. However care must be taken when there are existing signatures. If this field is omitted or set to False, no further inputs and outputs may be added to the PSBT.Rusty wonders if this flag can be flagged simply by omitting the redundant fields, PSBT_GLOBAL_INPUT_COUNT and PSBT_GLOBAL_OUTPUT_COUNT. Andrew explains that the purpose of these fields is to know how many input and output maps there are. Without PSBT_GLOBAL_UNSIGNED_TX, there is no way to determine whether a map is an input map or an output map. So the counts are there to allow that.Andrew goes on to mention that there are some protocols where signed inputs are added to transactions. He also suggests that if an explicit marker is required, he would omit the value and simply use its existence as a flag instead of having two "false" values.Rusty concludes the email thread by thanking Andrew for the progress and suggesting a potential name change from PSBT to PBT (Partial Bitcoin Transaction) due to its expanded functionality beyond signing.
Updated on: 2023-05-21T00:06:13.607596+00:00