Securing Emails using Secret Sharing

Securing Emails using Secret Sharing

Have you ever sent your confidential information such as passport and SSN over email?

Motivation• Most people have done it

• Email servers have confidential information about most people

Shamir Secret Sharing MUA• Secret: Any information that a user wishes to encrypt• Share: The resultant k pieces of information generated from the

secret, which will not yield any useful information on the secret until all shares are combined.

Application• Secure: Perfect information-theoretic security• Extensible: No share is significantly larger than the original secret• Fast: Computational overhead for generating shares and

reconstructing secrets is linear based on the number of shares generated and length of the secret.

System Architecture

• Each piece P represents a different email address to which a single share is sent.

• Share generation happens on the sending end.

• Secret reconstruction happens at the receiving end.

Why use this?• People should have the option to use completely secure email

systems• Connection between user and email provider is typically

encrypted and secure, but from then on there is no guarantee.• Using a web browser to interact with email is inherently insecure• Widely used public key encryption schemes are useless if an

intruder obtains the private key

Example Share Generation• S = 1234

Example Secret Reconstructionx y

1 1494

2 329

3 965

∴𝑆=1234

Next Steps• Collect data and write a research paper• Convert the program into an Android app