sekouperry/securesend

iOS encryption app based on CMS/SMIME standard of the Graz University of Technology

SecureSend

Introduction

SecureSend is a research project of the Institute for Applied Information Processing and Communications at the Graz University of Technology.

It is an iPhone application that provides the ability of sharing containers of data over the Internet in a secure and easy way. The primary focus was to keep it usable and secure without using a Public-Key Infrastructue (PKI) [1]. In order to avoid usability problems that normally occur when using a PKI for certificate verification and distribution, this application establishes a certain level of trust by introducing a Bluetooth and two-way key exchange. The containers are protected using the recipient's public-key out of the certificate, which is distributed either directly by Bluetooth or using the aforementioned two-channel exchange over Internet and GSM. The user can send the resulting encrypted container back to the owner of the certificate via email or share it using Dropbox [2]. Then the owner can decrypt it using his private key and access the user's sensitive data. The encryption and decryption is based on the CMS/SMIME standard and uses self-signed certificates.

Overview

SecureSend allows you to store files in secure containers on your iPhone and share these containers with other persons via eMail and Dropbox. The containers are protected from unauthorised access by using state-of-the-art encryption. Before sharing a container with another recipient the person's certificate can be retrieved via bluetooth or eMail.

Files from other applications can simply be added to a container by opening them in SecureSend (e.g. from your eMail client). We highly recommended to set a passcode for your iPhone. Only then, the files within SecureSend are adequately protected by using the iPhones data protection system.

Features:

• Securely store files in SecureSend
• Securely share data with other persons
• Exchange certificates via Bluetooth or Email

Screenshots

Technical details

SecureSend uses CMS/SMIME to create encrypted containers. In order to encrypt a container for a recipient, the X509 certificate of this person is required. SecureSend uses self-signed certificates that can be exchanged via eMail or Bluetooth. When exchanging certificates via eMail, a checksum (SHA1 hash value) is also sent via SMS that can be compared with the checksum of the received certificate. Due to the use of self-signed certificates (instead relying on a PKI), these two channels provide a higher level of trust than by using only an email for the exchanging certificates. For detailed information (including the source code of SecureSend) please visit the developer's website.

References

• [1] ... http://en.wikipedia.org/wiki/Public_key_infrastructure
• [2] ... http://www.dropbox.com