<P> The security of ATM transactions relies mostly on the integrity of the secure cryptoprocessor: the ATM often uses general commodity components that sometimes are not considered to be "trusted systems". </P> <P> Encryption of personal information, required by law in many jurisdictions, is used to prevent fraud . Sensitive data in ATM transactions are usually encrypted with DES, but transaction processors now usually require the use of Triple DES . Remote Key Loading techniques may be used to ensure the secrecy of the initialisation of the encryption keys in the ATM . Message Authentication Code (MAC) or Partial MAC may also be used to ensure messages have not been tampered with while in transit between the ATM and the financial network . </P> <P> There have also been a number of incidents of fraud by Man - in - the - middle attacks, where criminals have attached fake keypads or card readers to existing machines . These have then been used to record customers' PINs and bank card information in order to gain unauthorised access to their accounts . Various ATM manufacturers have put in place countermeasures to protect the equipment they manufacture from these threats . </P> <P> Alternative methods to verify cardholder identities have been tested and deployed in some countries, such as finger and palm vein patterns, iris, and facial recognition technologies . Cheaper mass - produced equipment has been developed and is being installed in machines globally that detect the presence of foreign objects on the front of ATMs, current tests have shown 99% detection success for all types of skimming devices . </P>

Where does the money in atms come from