Gangga Malayu was a cipher script used in the Malay peninsula until the early 1900s. Its origin is not known; the shapes of some letters seem to have been based on their Arabic equivalents, but structurally the script resembles a Brahmic abugida.
This script is not currently recognized by the ISO 15924 standard, but is included in ScriptSource for research purposes. If you have any information on this script, please add the information to this site. Your contributions can be a great help in refining and expanding the ISO 15924 standard. The Script Encoding Initiative is working to support the inclusion of this script in the standard, and contributions here will support their efforts.