A currency’s physical and digital security is paramount to protecting its value, especially as the currency becomes more widely adopted and the likelihood of fraud, counterfeiting, and hacking increases. This is common in national currencies, but is also an issue in some complementary and even some community currencies, particularly those that can be exchanged for national currency. 112 PEOPLE POWERED MONEY PEOPLE POWERED MONEY 113 PART02 C/05 Table 7: Anti-counterfeit measures or sale of environmentally friendly products and services, or being a small business. A more open membership can make it easier to grow the network of businesses in which the currency is accepted and to ensure a good variety of goods and services can be bought with the currency. With a more restrictive membership policy, growing the network and ensuring variety become harder; however, the currency can gain from having a stronger identity, as well as potentially helping it to meet certain objectives, such as encouraging local shopping, incentivising ethical choices or favouring small businesses over large multinationals. This chapter has covered some of the specifics of currency design in more detail. Combining this technical understanding with the advice on the design process in the previous chapter should help to ensure that currency projects are appropriate to their objectives, incorporating the right features, involving the right people and striking the right balance between clarity of purpose and flexibility of design. Rather than simply trying to replicate existing models that have been successful elsewhere, we hope that this will make it easier to focus on specific attributes of currency design and decide which are suitable and unsuitable for any particular context, community and goal. Next, we turn to the wider issue, far from specific to currencies, of implementing a long-term and complex project. Countermeasures with physical currencies through accounting practices identity verification measures (for electronic transactions and membership) in digital transactions - Security papers - Special printing techniques - Registered serial numbers - Watermarking - Holograms - Publicly accessible trading histories - Signatures or double signatures - Authorisation by different parties - Regular auditing - Authorisation requirements by phone or electronic validation - Voice recognition, facial recognition, other biometrics - In-app security questions - PIN or passwords - Password-secured user accounts - Chip and PIN technologies - Encryption (PGP, public-private key) - Third-party authentication