4. The computer-implemented method of claim 1 , wherein: the request for sharing the document comprises an identification of the second client device; the request to access the document comprises a portion of the document and the identification of the second client device; and determining, by the server system, that the second user associated with the second client device is authorized to access the document comprises: obtaining the document from a storage device; and prior to communicating the message including information about the document to the second client device, determining that the portion of the document from the request to access the document matches a corresponding portion of the document obtained from the storage device.
1. A computer-implemented method comprising: receiving, by a server system from a first client device associated with a first user, a request for sharing a document with a second client device, wherein the document is electronically signed using a credential of the first user, and the credential identifies one or more privileges allocated to the first user; in response to receiving the request for sharing the document with the second client device, generating, by the server system, a code that allows access to the document; transmitting, from the server system to the first client device, the code that allows access to the document; receiving, by the server system from the second client device, a request to access the document, the request to access the document including the code that allows access to the document; based on the request to access the document, determining, by the server system, that a second user associated with the second client device is authorized to access the document; and communicating, by the server system to the second client device, a message including information about the document based on determining that the second user associated with the second client device is authorized to access the document.