King Fahd University of Petroleum and Minerals

Ahmed Ibrahim Al-Herz

Mohammad K Ibrahim

Lahouari Ghouti

Virtual account based digital cash 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 virtual account based digital cash protocols provide strong protection of the 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, digital signatures and symmetric key protocols, which may be readily implemented in standard information security based systems based on cryptographic constructs. In addition, the protocols may be deployed in mobile, off-line, and on-line settings.

Virtual account based new digital cash protocols

The hybrid virtual account and token-based digital cash protocols provide a user with many pairs of secret and public keys. One of the pairs is the master pair, which consists of one master user private key and one master user public key. Other pairs are pseudonym pairs, wherein each consists of one pseudonym user private key and one pseudonym user public key. The use of a master key pair and pseudonym key pairs circumvents the need for blind signatures. None of the invention's protocols require blind signatures. The protocols comprise public key protocols, digital signatures and symmetric key protocols.

Hybrid virtual account and token-based digital cash protocols

The virtual account and token-based 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 has one master pair of private and public keys and many pseudonym pairs of private and public keys. The new protocols combine blind digital signature and pseudonym-based 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 depositing digital cash with a digital cash issuer. Pseudonym key pairs are used for spending the digital cash. Digital cash includes digital cash tokens in virtual accounts, which can be managed from a user's fixed or mobile computing platform.

Virtual account and token-based digital cash protocols

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.

Token based new digital cash protocols with combined blind digital signature and pseudonym authentication

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. In addition, the protocols may be deployed in mobile, off-line, and on-line settings.

Token based new digital cash protocols

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.

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Los Angeles, CA, United States of America

Ahmed Ibrahim Al-Herz