Secure transfer of digital tokens

A digital token holder comprising at least:

• a tamper-resistant store for storing digital tokens;
• communication means for enabling communication within a digital token handling domain only with one or more other token holders for the transfer of digital token to one of said other token holders;
• communication means for enabling communication outside the digital token handling domain only with predetermined trusted third parties including communication for receipt of a decryption key;
• means for encrypting and decrypting secure communications with token holders within the digital token handling domain, and with the predetermined third parties;
• control means for controlling the store of digital tokens according to a pre-programmed method of encrypted communication with other token holders within the digital token handling domain and predetermined trusted third parties to ensure secure exchange of digital tokens.

A method of exchange of digital tokens including the steps of:

• providing a secure digital token handling domain comprising a plurality of tamper-resistant electronic token holders, each token holder having the ability to process and store information relating to the transfer of digital token;
• each of the token holders communicating with a corresponding predetermined trusted third party to obtain a decryption key;
• a first of the token holders (DTH1) communicating with a second of the token holders (DTH2) by an exchange of one or more encrypted messages, wherein the respective decryption key obtained by the first and second token holder enables decryption of the encrypted messages send by the other token holder, wherein one of the encrypted messages includes an amount of digital token to be transferred from the first token holder to the second holder;
• transferring the amount of digital token according to the encrypted message including the amount.

A method of exchange of digital tokens including the steps of:

• providing a first digital token holder (DTH1) having a store for holding digital tokens and a first identification (ID1);
• providing a second digital token holder (DTH2) having a store for holding digital tokens and a second identification (ID2);
• providing the DTH2 with a private decryption key capable of decrypting a message encrypted with a public key derived from ID2;
• DTH1 receiving ID2;
• DTH1 receiving an amount of digital token to be transferred to DTH2;
• DTH1 encrypting the amount of digital token with the public key derived from ID2 to provide an encrypted message;
• DTH1 providing DTH2 with the encrypted message;
• DTH1 deducting the amount from its store of digital token;
• DTH2 using the decryption key to decrypt the encrypted message to obtain the amount of digital token to transfer;
• DTH2 adding the amount to its store of digital token.

A method of exchange of digital tokens in the form of digital cash including the steps of:

• providing a first digital cash holder (DCH1) having a store for holding digital tokens in the form of digital cash and a first identification (ID1);
• providing a second digital cash holder (DCH2) having a store for holding digital tokens in the form of digital cash and a second identification (ID2);
• a first trusted authority providing the DTH1 with a first private key capable of decrypting a message encrypted with a public key derived from ID1;
• providing the DCH2 with a second private key capable of decrypting a message encrypted with a public key including ID2 and the current date and a symmetrical key capable of encrypting a message that can be decrypted using a symmetrical decryption key;
• DCH1 providing DCH2 with ID1;
• DCH2 encrypting the symmetrical key and ID2 using a public key including ID1 and the current date to provide a first encrypted message;
• DCH2 providing DCH1 with the first encrypted message;
• DCH1 using the first decryption key to decrypt the first encrypted message to obtain the symmetrical key and ID2;
• DCH1 receiving an amount of digital cash to be transferred to DCH2;
• DCH1 encrypting the amount of digital cash with the symmetrical key to produce a second encrypted message;
• DCH1 encrypting the second encrypted message with a public key including ID2 and the current date to provide a third encrypted message;
• DCH1 providing DCH2 with the third encrypted message;
• DCH1 deducting the amount from its store of digital cash;
• DCH2 using the second decryption key to decrypt the third encrypted message to obtain the second encrypted message;
• DCH2 using the symmetrical decryption key to decrypt the second encrypted message to obtain the amount of digital cash to transfer;
• and
• DCH2 adding the amount to its store of digital cash.

A method of controlling a first digital token holder (DTH1) to transfer a digital token to a second digital token holder (DTH2), said DTH1 having a communication means for communicating with DTH2, a store for holding digital token and a first identification (ID1), said DTH2 having a second identification (ID2);

• receiving a private decryption key capable of decrypting a message encrypted with a public key derived from ID1;
• sending ID1 to DTH2 using the communication means;
• receiving a first encrypted message from DTH2 using the communication means;
• decrypting the first encrypted message using the private decryption key to obtain a symmetrical key capable of encrypting a message that can be decrypted using the symmetrical key or a decryption key based on the symmetrical key and ID2;
• receiving an amount of digital token to be transferred to DTH2;
• encrypting the amount of digital token with the symmetrical key to produce a second encrypted message;
• encrypting the second encrypted message with a public key derived from ID2 to provide a third encrypted message;
• sending the third encrypted message to DTH2 using the communication means;
• and
• deducting the amount from the store of digital token.

A method of controlling a first digital token holder (DTH1) to receive a digital token from a second digital token holder (DTH2), said DTH1 having a communication means for communicating with DTH2, a store for holding digital tokens and a first identification (ID1), said DTH2 having a second identification (ID2);

• receiving a private decryption key capable of decrypting a message encrypted with a public key derived from ID1;
• receiving ID2 from DTH2 using the communication means;
• encrypting a symmetrical key capable of encrypting a message that can be decrypted using the symmetrical key or a decryption key based on the symmetrical key and ID1 using a public key derived from ID2 to provide a first encrypted message;
• sending the first encrypted message to DTH2 using the communication means
• receiving a second encrypted message from DTH2 using the communication means;
• using the private decryption key to decrypt the second encrypted message to obtain a third encrypted message;
• using the symmetrical key or decryption key to decrypt the third encrypted message to obtain an amount of digital token transferred from DTH2;
• and
• adding the amount to the store of digital tokens.

A method of controlling a first digital token holder (DTH1) to transfer a digital token to a second digital token holder (DTH2), said DTH1 having a communication means for communicating with DTH2, a store for holding digital token and a first identification (ID1), said DTH2 having a second identification (ID2);

• receiving a private decryption key capable of decrypting a message encrypted with a public key derived from ID1;
• sending ID1 to DTH2 using the communication means;
• receiving a first encrypted message from DTH2 using the communication means;
• decrypting the first encrypted message using the private decryption key to obtain ID2;
• receiving an amount of digital token to be transferred to DTH2;
• encrypting the amount of digital token with a public key derived from ID2 to provide a second encrypted message;
• sending the second encrypted message to DTH2 using the communication means;
• and
• deducting the amount from the store of digital token.

A method of controlling a first digital token holder (DTH1) to receive a digital token from a second digital token holder (DTH2), said DTH1 having a communication means for communicating with DTH2, a store for holding digital tokens and a first identification (ID1), said DTH2 having a second identification (ID2);

• receiving a private decryption key capable of decrypting a message encrypted with a public key derived from ID1;
• receiving ID2 from DTH2 using the communication means;
• encrypting ID1 using a public key derived from ID2 to provide a first encrypted message;
• sending the first encrypted message to DTH2 using the communication means
• receiving a second encrypted message from DTH2 using the communication means;
• using the private decryption key to decrypt the second encrypted message to obtain an amount of digital token transferred from DTH2;
• and
• adding the amount to the store of digital tokens.