| 摘要 |
<p>A database system (200) comprising: a memory (204) containing multiple data records (108a, 108b, 108c, 108d, 108e, 108f, 108g), wherein each of the data records has a data record asymmetric key pair (120, 122) for cryptographic encryption and decryption, wherein each data record asymmetric key pair comprises a data record public key (122) and a data record private key (120), wherein the data contained in each of the multiple data records is encrypted by the data record public key, wherein the data record private key of each data record asymmetric key pair is encrypted with the public key of another asymmetric key pair; a set of user accounts (102a, 102b, 102c, 102d, 102e), wherein each of the user accounts has a user asymmetric key pair (110c, 112) for encryption and decryption, wherein each user asymmetric key pair has a user public key (112) and a user private key (110c); wherein data (124) is added to a data record (108c) by encrypting it with the data record public key (122); wherein access to the data record is granted to a user account (102c) by encrypting the data record private key (120) with the public key of an asymmetric cryptographic key pair whose encrypted private key is accessible from the user account via a sequence of successive decryptions of encrypted private keys; and wherein the data record private key allows decryption of the data record.</p> |
