Virtual account based digital cash protocols use a combination of blind digital signatures and pseudonym authentication with at least two pairs of public and private keys. A user is provided with one master pair of private and public keys and as many pseudonym pairs of private and public keys as desired. The resulting virtual account based hybrid protocols combine the advantages of blind digital signature and pseudonym authentication. Blind digital signatures based on the master pair of keys are used to withdraw digital cash from the user's bank account under the user's real identity. A pseudonym pair of keys is used for converting digital cash into virtual account based digital cash by a digital cash issuer. All pseudonyms can be used for spending the virtual account based digital cash. These protocols ensure anonymity when withdrawing digital cash from the user's account under the user's real identity in addition to providing pseudonym authentication when spending virtual cash based digital cash under a pseudonym.