Here in Brazil too, for instance the NF-e (electronic "nota fiscal", the English term seems to be "receipt", the documentation is at http://www.nfe.fazenda.gov.

Here in Brazil too, for instance the NF-e (electronic "nota fiscal", the English term seems to be "receipt", the documentation is at http://www.nfe.fazenda.gov.br http://www.nfe.fazenda.gov.br) and the recently released digital payment network (PIX, see https://www.bcb.gov.br/content/estabilidadefinanceira/cedsfn/Manual%20de%20Seguranca%20do%20PIX%20v3.1.pdf https://www.bcb.gov.br/content/estabilidadefinanceira/cedsfn... for the current release of the relevant manual) both use XMLDSig.