An application can read from one store and send data to another app to persist into another store.
The one issue I see is that to sync properly such app would need a changelist (with the vector clocks and stuff), and the only thing most credential stores provide is the current state and no history track. An app may implement such list to itself, though, outside of the OS credential storage - without actual credentials, just referring to the record IDs so it's not too sensitive.
Another is, such external app would need to repeatedly access the credential store. If there is no API to detect if the store is locked or not, it may either require to keep it unlocked, or spam user with access prompts or something like that.
Oh, and it would be problematic if the store pins records to the applications and doesn't allow e.g. Chrome to access Firefox passwords and vice versa. You'll need highly privileged access (root) or somehow hook another app and inject yourself into its address space (WinHook, Xposed, etc).
But e.g. Windows Vault <-> KDE or Gnome keyring sync is certainly possible. In theory. Don't know if anyone had ever implemented it in practice, though.
The one issue I see is that to sync properly such app would need a changelist (with the vector clocks and stuff), and the only thing most credential stores provide is the current state and no history track. An app may implement such list to itself, though, outside of the OS credential storage - without actual credentials, just referring to the record IDs so it's not too sensitive.
Another is, such external app would need to repeatedly access the credential store. If there is no API to detect if the store is locked or not, it may either require to keep it unlocked, or spam user with access prompts or something like that.
Oh, and it would be problematic if the store pins records to the applications and doesn't allow e.g. Chrome to access Firefox passwords and vice versa. You'll need highly privileged access (root) or somehow hook another app and inject yourself into its address space (WinHook, Xposed, etc).
But e.g. Windows Vault <-> KDE or Gnome keyring sync is certainly possible. In theory. Don't know if anyone had ever implemented it in practice, though.