Abstract: Digital cash token protocols employ two pairs of private and public keys. Each public key is certified separately and the protocols do not use any blind signature schemes. As a result, the digital cash token protocols provide strong protection of user privacy by using two certified public keys instead of a blind signature. One pair of certified keys consists of one master user private key and one master user public key. A second pair of certified keys consists of one pseudonym user private key and one pseudonym user public key. The use of a master key pair and a pseudonym key pair circumvents the need for blind signatures. As a result, the proposed protocols do not require blind signatures and do not add additional overhead and security requirements necessitated by conventional blind signature schemes. The protocols use public key protocols and digital signatures and symmetric key protocols, which may be readily implemented in standard information security based systems based on cryptographic constructs.

Abstract: Digital cash token 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 digital cash token 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 digital cash tokens by a digital cash issuer. All pseudonyms can be used for spending the digital cash tokens. 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 digital cash tokens under a pseudonym.

Abstract: Digital cash token 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 digital cash token 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 digital cash tokens by a digital cash issuer. All pseudonyms can be used for spending the digital cash tokens. 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 digital cash tokens under a pseudonym.

Abstract: Digital cash token protocols employ two pairs of private and public keys. Each public key is certified separately and the protocols do not use any blind signature schemes. As a result, the digital cash token protocols provide strong protection of user privacy by using two certified public keys instead of a blind signature. One pair of certified keys consists of one master user private key and one master user public key. A second pair of certified keys consists of one pseudonym user private key and one pseudonym user public key. The use of a master key pair and a pseudonym key pair circumvents the need for blind signatures. As a result, the proposed protocols do not require blind signatures and do not add additional overhead and security requirements necessitated by conventional blind signature schemes. The protocols use public key protocols and digital signatures and symmetric key protocols, which may be readily implemented in standard information security based systems based on cryptographic constructs.