Cipher suite

Abstract: A process is provided that allows an exportable SSL client to negotiate an encrypted session using strong encryption with a server if the server is allowed to use strong encryption. With this process, the SSL client is normally limited to export strength encryption. But, when it is communicating with an approved server, it is able to expand the available set of encryption algorithms to include stronger algorithms/key lengths. The process involves performing an SSL handshake twice. The process begins when a client, i.e. a user, wants to establish a session with a server. The client first initiates a network connection to the server. The first handshake between an export client and an approved server results in an SSL session that uses export strength encryption. This establishes a connection using an exportable cipher suite. The client examines the server's certificate obtained as part of the first handshake. If the server is not approved, the SSL session transfers application data that are protected by the export cipher. If the server is approved, then the client initiates a second handshake, this time allowing stronger cipher suites. The result of the second handshake is an SSL session that uses strong encryption. The SSL session may then be used to transfer application data that are protected by the strong cipher suite. At this point, the process is complete.

Abstract: The encryption of network traffic complicates legitimate network monitoring, traffic analysis, and network forensics. In this paper, we present real-time lightweight identification of HTTPS clients based on network monitoring and SSL/TLS fingerprinting. Our experiment shows that it is possible to estimate the User-Agent of a client in HTTPS communication via the analysis of the SSL/TLS handshake. The fingerprints of SSL/TLS handshakes, including a list of supported cipher suites, differ among clients and correlate to User-Agent values from a HTTP header. We built up a dictionary of SSL/TLS cipher suite lists and HTTP User-Agents and assigned the User-Agents to the observed SSL/TLS connections to identify communicating clients. The dictionary was used to classify live HTTPS network traffic. We were able to retrieve client types from 95.4 % of HTTPS network traffic. Further, we discussed host-based and network-based methods of dictionary retrieval and estimated the quality of the data.

Abstract: SSL is the de facto standard today for securing end-to-end transport on the Internet. While the protocol itself seems rather secure, there are a number of risks that lurk in its use, for example, in web banking. However, the adoption of password-based key-exchange protocols can overcome some of these problems. We propose the integration of such a protocol (DH-EKE) in the TLS protocol, the standardization of SSL by IETF. The resulting protocol provides secure mutual authentication and key establishment over an insecure channel. It does not have to resort to a PKI or keys and certificates stored on the users computer. Additionally, its integration in TLS is as minimal and non-intrusive as possible.

Abstract: The ChaCha20 stream cipher and the Poly1305 authenticator are cryptographic algorithms designed by Daniel J. Bernstein with the aim of ensuring high-security margins, while achieving high performance on a broad range of software platforms. In response to the concerns raised about the reliability of the existing IETF/TLS cipher suite, its performance on software platforms, and the ease to realize secure implementations thereof, the IETF has recently published the RFC7905 and RFC7539 to promote the use and standardization of the ChaCha20 stream cipher and Poly1305 authenticator in the TLS protocol. Most interestingly, the RFC7539 specifies how to combine together the ChaCha20 stream cipher and Poly1305 authenticator to construct an Authenticated Encryption with Associated Data (AEAD) scheme to provide confidentiality, integrity, and authenticity of data. In this work, we present compact, constant-time, and fast implementations of the ChaCha20 stream cipher, Poly1305-ChaCha20 authenticator, and ChaCha20-Poly1305 AEAD scheme for ARM Cortex-M4 processors, aimed at evaluating the suitability of such algorithms for high-speed and lightweight IoT applications, e.g. to deploy fast and secure TLS connections between IoT nodes and remote cloud servers, when AES hardware acceleration capabilities are not available.