Reissuing obligations to preserve privacy

Abstract

A system is provided for reissuing obligations whose ownership is recorded in a distributed ledger to preserve the identity of prior owners of the obligations. The system accesses a target transaction in which an issuer has a target obligation to a target owner specified in the target transaction. The target transaction has one or more ancestor transactions that each specify an owner. The system retires the target transaction so that the issuer no longer has the target obligation. The system then receives an indication that the issuer created a reissue transaction in which the issuer has a reissued obligation to the target owner that is specified in the reissue transaction. The reissue transaction does not have any ancestor transactions.

We claim: 
     
         1 . A method performed by one or more computing system for verifying a confidential identity of a first entity, the method comprising:
 accessing a signed first confidential identity certificate of the first entity that includes a first confidential public key of the first entity and a first well-known name of the first entity and that is signed using a first well-known private key of the first entity, the first confidential public key and a first confidential private key composing a first confidential public/private key; a first well-known public key and the first well-known private key composing a first well-known public/private key pair; and   verifying using the first well-known public key that the signed first confidential identity certificate was signed using the first well-known private key.   
     
     
         2 . The method of  claim 1  further comprising:
 accessing signed data that is signed using the first confidential private key; and 
 verifying, using the first confidential public key, that the data was signed using the first confidential public key. 
 
     
     
         3 . The method of  claim 1  further comprising:
 receiving from the first entity a first nonce; and 
 sending to the first entity a second nonce; 
 wherein the signed first confidential identity certificate is part of a signed hash derived based on the signed first confidential identity certificate, the first nonce, and the second nonce. 
 
     
     
         4 . The method of  claim 3  wherein the verifying further verifies that signed hash is derived based on the first nonce and the second nonce. 
     
     
         5 . The method of  claim 1  further comprising:
 receiving a second confidential public key and signed data that is signed using a second confidential private key and; and 
 verifying, using the second confidential public key, that the data was signed using the second confidential private key. 
 
     
     
         6 . The method of  claim 5  wherein the signed data is a transaction to which a second entity is a party, the transaction including the second confidential public key. 
     
     
         7 . The method of  claim 5  wherein multiple first confidential identity certificates are generated for signing different data. 
     
     
         8 . The method of  claim 1  wherein the signed first confidential public key is signed in combination with an identifier of the first entity wherein the signed combination forms a first confidential identity certificate. 
     
     
         9 . The method of  claim 2  wherein the data is a transaction that identifies the first entity by the first confidential public key. 
     
     
         10 . The method of  claim 9  wherein output of the transaction is input to another transaction to which the first entity is a party. 
     
     
         11 . At least one non-transitory, computer-readable medium carrying instructions, which when executed by at least one data processor, performs operations for verifying a confidential identity of a first entity, the operations comprising:
 accessing a signed first confidential identity certificate of the first entity that includes a first confidential public key of the first entity and a first well-known name of the first entity and that is signed using a first well-known private key of the first entity, the first confidential public key and a first confidential private key composing a first confidential public/private key; a first well-known public key and the first well-known private key composing a first well-known public/private key pair; and   verifying using the first well-known public key that the signed first confidential identity certificate was signed using the first well-known private key.   
     
     
         12 . The computer-readable medium of  claim 11  further comprising:
 receiving signed data that is signed using the first confidential private key; and 
 verifying, using the first confidential public key, that the data was signed using the first confidential public key. 
 
     
     
         13 . The computer-readable medium of  claim 11 , wherein the operations further comprise:
 receiving from the first entity a first nonce; and   sending to the first entity a second nonce;   wherein the signed first confidential identity certificate is part of a signed hash derived based on the signed first confidential identity certificate, the first nonce, and the second nonce.   
     
     
         14 . The computer-readable medium of  claim 13  wherein the verifying further verifies that signed hash is derived based on the first nonce and the second nonce. 
     
     
         15 . One or more computing systems for verifying an identity of a first entity, the one or more computing system comprising:
 one or more computer-readable storage mediums for storing computer-executable instructions for controlling the one or more computing systems to:
 access a signed first confidential public key of the first entity and that is signed using a first well-known private key of the first entity, the first confidential public key and a first confidential private key composing a first confidential public/private key, a first well-known public key and the first well-known private key composing a first well-known public/private key pair; 
 verify using the first well-known public key that the signed first confidential public key was signed using the first well-known private key; 
 access signed data that is data that is signed using the first confidential private key; and 
 verify that the first entity signed the data using the signed first confidential public key; and 
   one or more processors for executing the computer-executable instructions stored in the one or more computer-readable storage mediums.   
     
     
         16 . The one or more computing systems of  claim 15  wherein the signed first confidential public key is signed in combination with an identifier of the first entity wherein the signed combination forms a first confidential identity certificate. 
     
     
         17 . The one or more computing systems of  claim 16  wherein the instructions further:
 receive from the first entity a first nonce; and 
 send to the first entity a second nonce, 
 wherein the signed first confidential public key is part of a signed hash derived based on the first nonce and the second nonce, the first confidential identity certificate being received as part of receiving the signed hash. 
 
     
     
         18 . The one or more computing systems of  claim 17  wherein the verifying further verifies that signed hash is derived based on the first nonce and the second nonce. 
     
     
         19 . The one or more computing systems of  claim 15  wherein the data is a transaction that identifies the first entity by the first confidential public key. 
     
     
         20 . The one or more computing systems of  claim 19  wherein output of the transaction is input to another transaction to which the first entity is a party.