File sharing method and apparatus

1. A file sharing method, comprising:

encrypting, by a first terminal, a first file by using a first shared key to obtain a first encrypted file;

encrypting, by the first terminal, a second file by using a second shared key to obtain a second encrypted file;

uploading, by the first terminal, the first encrypted file and the second encrypted file to a server;

receiving, by the first terminal, a first uniform resource locator (URL) corresponds to a location for saving the first encrypted file and a second URL corresponds to a location for saving the second encrypted file from the server;

generating, by the first terminal, a key package of a file to be shared, wherein the file to be shared comprises at least one of the first encrypted file and the second encrypted file, and wherein the key package comprises a shared key and a URL that correspond to the file to be shared; and

providing, by the first terminal, the key package for a second terminal, comprising:

encrypting, by the first terminal, the key package by using a public key of the first terminal to obtain an encrypted key package;

acquiring, by the first terminal, a public key of the second terminal;

generating, by the first terminal, a proxy key according to a private key of the first terminal and the public key of the second terminal; and

uploading, by the first terminal, the encrypted key package and the proxy key to the server, so that the server performs proxy re-encryption on the encrypted key package by using the proxy key, and provides, for the second terminal, the key package on which the proxy re-encryption has been performed.

2. The method according to claim 1 , wherein providing, by the first terminal, the key package for the second terminal comprises:

encrypting, by the first terminal, the key package to obtain an encrypted key package;

transmitting, by the first terminal, the encrypted key package to the second terminal.

3. The method according to claim 1 , wherein the server comprises:

a cloud server; and

a trusted server used for storing a key package, wherein uploading, by the first terminal, the first encrypted file and the second encrypted file to a server comprises uploading, by the first terminal, the first encrypted file and the second encrypted file to the cloud server, and wherein providing, by the first terminal, the key package for the second terminal comprises:

uploading, by the first terminal, the key package to the trusted server;

receiving, by the first terminal, a URL that is returned by the trusted server and corresponds to a location for saving the key package; and

sending, by the first terminal, to the second terminal, the URL corresponding to the location for saving the key package.

4. The method according to claim 3 , wherein before sending, by the first terminal, to the second terminal, the URL corresponding to the location for saving the key package, the method further comprises sending, by the first terminal, an authorization message for the second terminal to the trusted server, to permit the second terminal to acquire the key package from the trusted server.

5. A file sharing method, comprising:

receiving, by a cloud server, a first encrypted file and a second encrypted file uploaded by a first terminal;

saving, by the cloud server, the first encrypted file and the second encrypted file;

returning, by the cloud server to the first terminal, a first uniform resource locator (URL) corresponds to a first location for saving the first encrypted file and a second URL corresponds to a second location for saving the second encrypted file;

receiving, by the cloud server, a key package of a file to be shared, which is uploaded by the first terminal and encrypted by using a public key of the first terminal, wherein the file to be shared comprises at least one of the first encrypted file and the second encrypted file, and wherein the key package comprises a shared key and a URL that correspond to the file to be shared;

receiving, by the cloud server, a proxy key uploaded by the first terminal, wherein the proxy key is generated by the first terminal according to a private key of the first terminal and a public key of the second terminal, wherein providing, by the cloud server, the key package for the second terminal comprises:

performing, by the cloud server, proxy re-encryption on the key package by using the proxy key; and

providing, by the cloud server, the key package on which the proxy re-encryption has been performed for the second terminal; and

providing, by the cloud server, the key package for a second terminal.

6. A file sharing apparatus, wherein the file sharing apparatus is comprised in a first terminal, the file sharing apparatus comprising:

a memory storing executable instructions;

a processor coupled to the memory and configured to:

encrypt a first file by using a first shared key to obtain a first encrypted file; and

encrypt a second file by using a second shared key to obtain a second encrypted file;

a transmitter coupled to the processor and configured to:

upload the first encrypted file and the second encrypted file to a server; and

receive a first uniform resource locator (URL) corresponds to a first location for saving the first encrypted file and a second URL corresponds to a second location for saving the second encrypted file from the server,

wherein the processor is further configured to:

generate a key package of a file to be shared, wherein the file to be shared comprises at least one of the first encrypted file and the second encrypted file, and wherein the key package comprises a shared key and a URL that correspond to the file to be shared;

provide the key package for a second terminal;

encrypt the key package by using a public key of the first terminal to obtain an encrypted key package;

acquire a public key of the second terminal;

generate a proxy key according to a private key of the first terminal and the public key of the second terminal; and

upload the encrypted key package and the proxy key to the server, so that the server performs proxy re-encryption on the encrypted key package by using the proxy key, and provides, for the second terminal, the key package on which the proxy re-encryption has been performed.

7. The apparatus according to claim 6 , wherein the processor is further configured to:

encrypt the key package to obtain an encrypted key package; and

transmit the encrypted key package to the second terminal.

8. The apparatus according to claim 6 , wherein the server comprises:

a cloud server; and

a trusted server used for storing a key package, wherein the transmitter is further configured to upload the first encrypted file and the second encrypted file to the cloud server, and wherein the processor is further configured to:

upload the key package to the trusted server;

receive a URL that is returned by the trusted server and corresponds to a location for saving the key package; and

send, to the second terminal, the URL corresponding to the location for saving the key package.

9. The apparatus according to claim 8 , wherein before sending, to the second terminal, the URL corresponding to the location for saving the key package, the processor is further configured to send an authorization message for the second terminal to the trusted server to permit the second terminal to acquire the key package from the trusted server.

10. A file sharing apparatus, comprising:

a first receiver configured to receive and save a first encrypted file and a second encrypted file uploaded by a first terminal;

a transmitter configured to return, to the first terminal, a first uniform resource locator (URL) corresponds to a first location for saving the first encrypted file and a second URL corresponds to a second location for saving the second encrypted file;

a second receiver configured to:

receive a key package of a file to be shared uploaded by the first terminal and encrypted by using a public key of the first terminal, wherein the file to be shared comprises at least one of the first encrypted file and the second encrypted file, and wherein the key package comprises a shared key and a URL that correspond to the file to be shared; and

receive a proxy key uploaded by the first terminal, wherein the proxy key is generated by the first terminal according to a private key of the first terminal and a public key of the second terminal; and

a processor coupled to the first receiver, the second receiver, and the transmitter and configured to:

provide the key package for a second terminal;

perform proxy re-encryption on the key package by using the proxy key; and

provide, for the second terminal, the key package on which the proxy re-encryption has been performed.