Biblio

Security in the communication systems rely mainly on a trusted Public Key Infrastructure (PKI) and Certificate Authorities (CAs). Besides the lack of automation, the complexity and the cost of assigning a signed certificate to a device, several allegations against CAs have been discovered, which has created trust issues in adopting this standard model for secure systems. The automation of the servers certificate assignment was achieved by the Automated Certificate Management Environment (ACME) method, but without confirming the trust of assigned certificate. This paper presents a complete tested and implemented solution to solve the trust of the Certificates provided to the servers by using the blockchain platform for certificate validation. The Blockchain network provides an immutable data store, holding the public keys of all domain names, while resolving the trust concerns by applying an automated Blockchain-based Domain Control Validation (B-DCV) for the server and client server verification. The evaluation was performed on the Ethereum Rinkeby testnet adopting the Proof of Authority (PoA) consensus algorithm which is an improved version of Proof of Stake (Po \$S\$) applied on Ethereum 2.0 providing superior performance compared to Ethereum 1.0.

Ethical bias in machine learning models has become a matter of concern in the software engineering community. Most of the prior software engineering works concentrated on finding ethical bias in models rather than fixing it. After finding bias, the next step is mitigation. Prior researchers mainly tried to use supervised approaches to achieve fairness. However, in the real world, getting data with trustworthy ground truth is challenging and also ground truth can contain human bias. Semi-supervised learning is a technique where, incrementally, labeled data is used to generate pseudo-labels for the rest of data (and then all that data is used for model training). In this work, we apply four popular semi-supervised techniques as pseudo-labelers to create fair classification models. Our framework, Fair-SSL, takes a very small amount (10%) of labeled data as input and generates pseudo-labels for the unlabeled data. We then synthetically generate new data points to balance the training data based on class and protected attribute as proposed by Chakraborty et al. in FSE 2021. Finally, classification model is trained on the balanced pseudo-labeled data and validated on test data. After experimenting on ten datasets and three learners, we find that Fair-SSL achieves similar performance as three state-of-the-art bias mitigation algorithms. That said, the clear advantage of Fair-SSL is that it requires only 10% of the labeled training data. To the best of our knowledge, this is the first SE work where semi-supervised techniques are used to fight against ethical bias in SE ML models. To facilitate open science and replication, all our source code and datasets are publicly available at https://github.com/joymallyac/FairSSL. CCS CONCEPTS • Software and its engineering → Software creation and management; • Computing methodologies → Machine learning. ACM Reference Format: Joymallya Chakraborty, Suvodeep Majumder, and Huy Tu. 2022. Fair-SSL: Building fair ML Software with less data. In International Workshop on Equitable Data and Technology (FairWare ‘22), May 9, 2022, Pittsburgh, PA, USA. ACM, New York, NY, USA, 8 pages. https://doi.org/10.1145/3524491.3527305

Nowadays, encrypted traffic classification has become a challenge for network monitoring and cyberspace security. However, the existing methods cannot meet the requirements of encrypted traffic classification because of the encryption protocol in communication. Therefore, we design a novel neural network named Stereo Transform Neural Network (STNN) to classify encrypted network traffic. In STNN, we combine Long Short Term Memory (LSTM) and Convolution Neural Network (CNN) based on statistical features. STNN gains average precision about 95%, average recall about 95%, average F1-measure about 95% and average accuracy about 99.5% in multi-classification. Besides, the experiment shows that STNN obviously accelerates the convergence rate and improves the classification accuracy.

Classifying Hyperspectral images with few training samples is a challenging problem. The generative adversarial networks (GAN) are promising techniques to address the problems. GAN constructs an adversarial game between a discriminator and a generator. The generator generates samples that are not distinguishable by the discriminator, and the discriminator determines whether or not a sample is composed of real data. In this paper, by introducing multilayer features fusion in GAN and a dynamic neighborhood voting mechanism, a novel algorithm for HSIs classification based on 1-D GAN was proposed. Extracting and fusing multiple layers features in discriminator, and using a little labeled samples, we fine-tuned a new sample 1-D CNN spectral classifier for HSIs. In order to improve the accuracy of the classification, we proposed a dynamic neighborhood voting mechanism to classify the HSIs with spatial features. The obtained results show that the proposed models provide competitive results compared to the state-of-the-art methods.

We propose an efficient and secure two-server password-only remote user authentication protocol for consumer electronic devices, such as smartphones and laptops. Our protocol works on-top of any existing trust model, like Secure Sockets Layer protocol (SSL). The proposed protocol is secure against dictionary and impersonation attacks.

SSL certificates are a core component of the public key infrastructure that underpins encrypted communication in the Internet. In this paper, we report the results of a longitudinal study of the characteristics of SSL certificate chains presented to clients during secure web (HTTPS) connection setup. Our data set consists of 23B SSL certificate chains collected from a global panel consisting of over 2M residential client machines over a period of 6 months. The data informing our analyses provide perspective on the entire chain of trust, including root certificates, across a wide distribution of client machines. We identify over 35M unique certificate chains with diverse relationships at all levels of the PKI hierarchy. We report on the characteristics of valid certificates, which make up 99.7% of the total corpus. We also examine invalid certificate chains, finding that 93% of them contain an untrusted root certificate and we find they have shorter average chain length than their valid counterparts. Finally, we examine two unintended but prevalent behaviors in our data: the deprecation of root certificates and secure traffic interception. Our results support aspects of prior, scan-based studies on certificate characteristics but contradict other findings, highlighting the importance of the residential client-side perspective.

This paper studies and describes encrypted communication between IoT cloud and IoT embedded systems. It uses encrypted MQTTS protocol with SSL/TLS certificate. A JSON type data format is used between the cloud structure and the IoT device. The embedded system used in this experiment is Esp32 Wrover. The IoT embedded system measures temperature and humidity from a sensor DHT22. The architecture and software implementation of the experimental stage are also presented.

With evolution of the communication technology remote monitoring has rooted into many applications. Swift innovation in Internet of Things (IoT) technology led to development of electronics embedded devices capable of sensing into the remote location and transferring the data through internet across the globe. Such devices transfers the sensitive data, which are susceptible to security attacks by the intruder and network hacker. Paper studies the existing security solutions and limitations for IoT environment and provides a pragmatic lightweight security scheme on Transmission Control Protocol (TCP) network for Remote Monitoring System devices over internet. This security scheme will aid Original Equipment Manufacturer (OEM) developing massive IoT products for remote monitoring. Real time evaluation of this scheme has been analyzed.

Software Defined Network (SDN) is a revolutionary networking paradigm which provides the flexibility of programming the network interface as per the need and demand of the user. Software Defined Network (SDN) is independent of vendor specific hardware or protocols and offers the easy extensions in the networking. A customized network as per on user demand facilitates communication control via a single entity i.e. SDN controller. Due to this SDN Controller has become more vulnerable to SDN security attacks and more specifically a single point of failure. It is worth noticing that vulnerabilities were identified because of customized applications which are semi-independent of underlying network infrastructure. No doubt, SDN has provided numerous benefits like breaking vendor lock-ins, reducing overhead cost, easy innovations, increasing programmability among devices, introducing new features and so on. But security of SDN cannot be neglected and it has become a major topic of debate. The communication channel used in SDN is OpenFlow which has made TLS implementation an optional approach in SDN. TLS adoption is important and still vulnerable. This paper focuses on making SDN OpenFlow communication more secure by following extended TLS support and defensive algorithm.

In this paper, development of cyber communication package in the application of grid connected solar system has been presented. Here, implemented communication methodology supports communication process with reduced latency, high security arrangement with various degrees of freedom. Faithful transferring of various electrical data for the purpose of measurement, monitoring and controlling actions depend on the bidirectional communication strategy. Thus, real-time communication of data through cyber network has been emphasized in this paper. The C\# language based coding is done to develop the communication program. The notable features of proposed communication process are reduction of latency during data exchange by usage of advanced encryption standard (AES) algorithm, tightening of cyber security arrangement by implementing secured socket layer (SSL) and Rivest, Shamir and Adleman (RSA) algorithms. Various real-time experiments using internet connected computers have been done to verify the usability of the proposed communication concept along with its notable features in the application.

The Time and the Time Synchronization are veryimportant especially for the computer networks performing timesensitive operations. It is very important for all the datacenters, markets, finance companies, industrial networks, commercial applications, e-mail and communication-related Clients and servers, active directory services, authentication mechanisms, and wired and wireless communication. For instance. a sensitive time system is crucial for financial networks processing a large amount of data on a daily basis. If the computer does not communicate with other Computers Or Other systems using time, then the time information might not be important. The NTP acts as a Single time source in order to synchronize all the devices in a network. While the computer networks communicate with each other between different time zones and different locations on the earth; the main time doesn't need to be the same all around the world but it must be very sensitive otherwise the networks at different locations might work on different times.As the main time sources, most of networks uses the Coordinated Universal Time The is important also for security. The hackers and the malware such as computer Viruses use the time inconsistencies in order to overcome all the security measures such as firewalls or antivirus software; without a correct time, any system might be taken under control. If all the devices are connected to STP time. then it would be more difficult for malicious to the System.

With the unprecedented prevalence of mobile network applications, cryptographic protocols, such as the Secure Socket Layer/Transport Layer Security (SSL/TLS), are widely used in mobile network applications for communication security. The proven methods for encrypted video stream classification or encrypted protocol detection are unsuitable for the SSL/TLS traffic. Consequently, application-level traffic classification based networking and security services are facing severe challenges in effectiveness. Existing encrypted traffic classification methods exhibit unsatisfying accuracy for applications with similar state characteristics. In this paper, we propose a multiple-attribute-based encrypted traffic classification system named Multi-Attribute Associated Fingerprints (MAAF). We develop MAAF based on the two key insights that the DNS traces generated during the application runtime contain classification guidance information and that the handshake certificates in the encrypted flows can provide classification clues. Apart from the exploitation of key insights, MAAF employs the context of the encrypted traffic to overcome the attribute-lacking problem during the classification. Our experimental results demonstrate that MAAF achieves 98.69% accuracy on the real-world traceset that consists of 16 applications, supports the early prediction, and is robust to the scale of the training traceset. Besides, MAAF is superior to the state-of-the-art methods in terms of both accuracy and robustness.

Many governments organizations in Libya have started transferring traditional government services to e-government. These e-services will benefit a wide range of public. However, deployment of e-government bring many new security issues. Attackers would take advantages of vulnerabilities in these e-services and would conduct cyber attacks that would result in data loss, services interruptions, privacy loss, financial loss, and other significant loss. The number of vulnerabilities in e-services have increase due to the complexity of the e-services system, a lack of secure programming practices, miss-configuration of systems and web applications vulnerabilities, or not staying up-to-date with security patches. Unfortunately, there is a lack of study being done to assess the current security level of Libyan government websites. Therefore, this study aims to assess the current security of 16 Libyan government websites using penetration testing framework. In this assessment, no exploits were committed or tried on the websites. In penetration testing framework (pen test), there are four main phases: Reconnaissance, Scanning, Enumeration, Vulnerability Assessment and, SSL encryption evaluation. The aim of a security assessment is to discover vulnerabilities that could be exploited by attackers. We also conducted a Content Analysis phase for all websites. In this phase, we searched for security and privacy policies implementation information on the government websites. The aim is to determine whether the websites are aware of current accepted standard for security and privacy. From our security assessment results of 16 Libyan government websites, we compared the websites based on the number of vulnerabilities found and the level of security policies. We only found 9 websites with high and medium vulnerabilities. Many of these vulnerabilities are due to outdated software and systems, miss-configuration of systems and not applying the latest security patches. These vulnerabilities could be used by cyber hackers to attack the systems and caused damages to the systems. Also, we found 5 websites didn't implement any SSL encryption for data transactions. Lastly, only 2 websites have published security and privacy policies on their websites. This seems to indicate that these websites were not concerned with current standard in security and privacy. Finally, we classify the 16 websites into 4 safety categories: highly unsafe, unsafe, somewhat unsafe and safe. We found only 1 website with a highly unsafe ranking. Based on our finding, we concluded that the security level of the Libyan government websites are adequate, but can be further improved. However, immediate actions need to be taken to mitigate possible cyber attacks by fixing the vulnerabilities and implementing SSL encryption. Also, the websites need to publish their security and privacy policy so the users could trust their websites.

The security of web communication via the SSL/TLS protocols relies on safe distributions of public keys associated with web domains in the form of X.509 certificates. Certificate authorities (CAs) are trusted third parties that issue these certificates. However, the CA ecosystem is fragile and prone to compromises. Starting with Google's Certificate Transparency project, a number of research works have recently looked at adding transparency for better CA accountability, effectively through public logs of all certificates issued by certification authorities, to augment the current X.509 certificate validation process into SSL/TLS. In this paper, leveraging recent progress in blockchain technology, we propose a novel system, called CTB, that makes it impossible for a CA to issue a certificate for a domain without obtaining consent from the domain owner. We further make progress to equip CTB with certificate revocation mechanism. We implement CTB using IBM's Hyperledger Fabric blockchain platform. CTB's smart contract, written in Go, is provided for complete reference.

Bitcoin provides freshness properties by forming a blockchain where each block is associated with its timestamp and the previous block. Due to these properties, the Bitcoin protocol is being used as a decentralized, trusted, and secure timestamping service. Although Bitcoin participants which create new blocks cannot modify their order, they can manipulate timestamps almost undetected. This undermines the Bitcoin protocol as a reliable timestamping service. In particular, a newcomer that synchronizes the entire blockchain has a little guarantee about timestamps of all blocks. In this paper, we present a simple yet powerful mechanism that increases the reliability of Bitcoin timestamps. Our protocol can provide evidence that a block was created within a certain time range. The protocol is efficient, backward compatible, and surprisingly, currently deployed SSL/TLS servers can act as reference time sources. The protocol has many applications and can be used for detecting various attacks against the Bitcoin protocol.

In recent years, real-world attacks against PKI take place frequently. For example, malicious domains' certificates issued by compromised CAs are widespread, and revoked certificates are still trusted by clients. In spite of a lot of research to improve the security of SSL/TLS connections, there are still some problems unsolved. On one hand, although log-based schemes provided certificate audit service to quickly detect CAs' misbehavior, the security and data consistency of log servers are ignored. On the other hand, revoked certificates checking is neglected due to the incomplete, insecure and inefficient certificate revocation mechanisms. Further, existing revoked certificates checking schemes are centralized which would bring safety bottlenecks. In this paper, we propose a blockchain-based public and efficient audit scheme for TLS connections, which is called Certchain. Specially, we propose a dependability-rank based consensus protocol in our blockchain system and a new data structure to support certificate forward traceability. Furthermore, we present a method that utilizes dual counting bloom filter (DCBF) with eliminating false positives to achieve economic space and efficient query for certificate revocation checking. The security analysis and experimental results demonstrate that CertChain is suitable in practice with moderate overhead.

Modern applications often involve processing of sensitive information. However, the lack of privilege separation within the user space leaves sensitive application secret such as cryptographic keys just as unprotected as a "hello world" string. Cutting-edge hardware-supported security features are being introduced. However, the features are often vendor-specific or lack compatibility with older generations of the processors. The situation leaves developers with no portable solution to incorporate protection for the sensitive application component. We propose LOTRx86, a fundamental and portable approach for user-space privilege separation. Our approach creates a more privileged user execution layer called PrivUser by harnessing the underused intermediate privilege levels on the x86 architecture. The PrivUser memory space, a set of pages within process address space that are inaccessible to user mode, is a safe place for application secrets and routines that access them. We implement the LOTRx86 ABI that exports the privcall interface to users to invoke secret handling routines in PrivUser. This way, sensitive application operations that involve the secrets are performed in a strictly controlled manner. The memory access control in our architecture is privilege-based, accessing the protected application secret only requires a change in the privilege, eliminating the need for costly remote procedure calls or change in address space. We evaluated our platform by developing a proof-of-concept LOTRx86-enabled web server that employs our architecture to securely access its private key during an SSL connection. We conducted a set of experiments including a performance measurement on the PoC on both Intel and AMD PCs, and confirmed that LOTRx86 incurs only a limited performance overhead.

Infrastructure-as-a-Service (IaaS), more generally the "cloud," changed the landscape of system operations on the Internet. Clouds' elasticity allow operators to rapidly allocate and use resources as needed, from virtual machines, to storage, to IP addresses, which is what made clouds popular. We show that the dynamic component paired with developments in trust-based ecosystems (e.g., TLS certificates) creates so far unknown attacks. We demonstrate that it is practical to allocate IP addresses to which stale DNS records point. Considering the ubiquity of domain validation in trust ecosystems, like TLS, an attacker can then obtain a valid and trusted certificate. The attacker can then impersonate the service, exploit residual trust for phishing, or might even distribute malicious code. Even worse, an aggressive attacker could succeed in less than 70 seconds, well below common time-to-live (TTL) for DNS. In turn, she could exploit normal service migrations to obtain a valid certificate, and, worse, she might not be bound by DNS records being (temporarily) stale. We introduce a new authentication method for trust-based domain validation, like IETF's automated certificate management environment (ACME), that mitigates staleness issues without incurring additional certificate requester effort by incorporating the existing trust of a name into the validation process. Based on previously published work [1]. [1] Kevin Borgolte, Tobias Fiebig, Shuang Hao, Christopher Kruegel, Giovanni Vigna. February 2018. Cloud Strife: Mitigating the Security Risks of Domain-Validated Certificates. In Proceedings of the 25th Network and Distributed Systems Security Symposium (NDSS '18). Internet Society (ISOC). DOI: 10.14722/ndss.2018.23327. URL: https://doi.org/10.14722/nd

Currently, no major browser fully checks for TLS/SSL certificate revocations. This is largely due to the fact that the deployed mechanisms for disseminating revocations (CRLs, OCSP, OCSP Stapling, CRLSet, and OneCRL) are each either incomplete, insecure, inefficient, slow to update, not private, or some combination thereof. In this paper, we present CRLite, an efficient and easily-deployable system for proactively pushing all TLS certificate revocations to browsers. CRLite servers aggregate revocation information for all known, valid TLS certificates on the web, and store them in a space-efficient filter cascade data structure. Browsers periodically download and use this data to check for revocations of observed certificates in real-time. CRLite does not require any additional trust beyond the existing PKI, and it allows clients to adopt a fail-closed security posture even in the face of network errors or attacks that make revocation information temporarily unavailable. We present a prototype of name that processes TLS certificates gathered by Rapid7, the University of Michigan, and Google's Certificate Transparency on the server-side, with a Firefox extension on the client-side. Comparing CRLite to an idealized browser that performs correct CRL/OCSP checking, we show that CRLite reduces latency and eliminates privacy concerns. Moreover, CRLite has low bandwidth costs: it can represent all certificates with an initial download of 10 MB (less than 1 byte per revocation) followed by daily updates of 580 KB on average. Taken together, our results demonstrate that complete TLS/SSL revocation checking is within reach for all clients.

Trust in SSL-based communications is provided by Certificate Authorities (CAs) in the form of signed certificates. Checking the validity of a certificate involves three steps: (i) checking its expiration date, (ii) verifying its signature, and (iii) ensuring that it is not revoked. Currently, such certificate revocation checks are done either via Certificate Revocation Lists (CRLs) or Online Certificate Status Protocol (OCSP) servers. Unfortunately, despite the existence of these revocation checks, sophisticated cyber-attackers, may trick web browsers to trust a revoked certificate, believing that it is still valid. Consequently, the web browser will communicate (over TLS) with web servers controlled by cyber-attackers. Although frequently updated, nonced, and timestamped certificates may reduce the frequency and impact of such cyber-attacks, they impose a very large overhead to the CAs and OCSP servers, which now need to timestamp and sign on a regular basis all the responses, for every certificate they have issued, resulting in a very high overhead. To mitigate this overhead and provide a solution to the described cyber-attacks, we present CCSP: a new approach to provide timely information regarding the status of certificates, which capitalizes on a newly introduced notion called signed collections. In this paper, we present the design, preliminary implementation, and evaluation of CCSP in general, and signed collections in particular. Our preliminary results suggest that CCSP (i) reduces space requirements by more than an order of magnitude, (ii) lowers the number of signatures required by 6 orders of magnitude compared to OCSP-based methods, and (iii) adds only a few milliseconds of overhead in the overall user latency.

Intel Software Guard Extension (SGX) offers software applications a shielded execution environment, dubbed enclave, to protect their confidentiality and integrity from malicious operating systems. As processors with this extended feature become commercially available, many new software applications are developed to enrich to the SGX-enabled ecosystem. One important primitive for these applications is a secure communication channel between the enclave and a remote trusted party. The SSL/TLS protocol, which is the de facto standard for protecting transport-layer network communications, has been broadly regarded a natural choice for such purposes. However, in this paper, we show that the marriage between SGX and SSL may not be smooth sailing. Particularly, we consider a category of side-channel attacks against SSL/TLS implementations in secure enclaves, which we call the control-flow inference attacks. In these attacks, the malicious operating system kernel may perform a powerful man-in-the-kernel attack to collect execution traces of the enclave programs at the page level, the cacheline level, or the branch level, while positioning itself in the middle of the two communicating parties. At the center of our work is a differential analysis framework, dubbed Stacco, to dynamically analyze the SSL/TLS implementations and detect vulnerabilities-discernible execution traces-that can be exploited as decryption oracles. Surprisingly, in spite of the prevailing constant-time programming paradigm adopted by many cryptographic libraries, we found exploitable vulnerabilities in the latest versions of all the SSL/TLS libraries we have examined. To validate the detected vulnerabilities, we developed a man-in-the-kernel adversary to demonstrate Bleichenbacher attacks against the latest OpenSSL library running in the SGX enclave (with the help of Graphene) and completely broke the PreMasterSecret encrypted by a 4096-bit RSA public key with only 57286 queries. We also conducted CBC padding oracle attacks against the latest GnuTLS running in Graphene-SGX and an open-source SGX implementation of mbedTLS (i.e., mbedTLS-SGX) that runs directly inside the enclave, and showed that it only needs 48388 and 25717 queries, respectively, to break one block of AES ciphertext. Empirical evaluation suggests these man-in-the-kernel attacks can be completed within 1 or 2 hours. Our results reveal the insufficient understanding of side-channel security in SGX settings, and our study will provoke discussions on the secure implementation and adoption of SSL/TLS in secure enclaves.

Protecting the customer's SSL private key is the paramount issue to persuade the website owners to migrate their contents onto the cloud infrastructure, besides the advantages of cloud infrastructure in terms of flexibility, efficiency, scalability and elasticity. The emerging Keyless SSL solution retains on-premise custody of customers' SSL private keys on their own servers. However, it suffers from significant performance degradation and limited scalability, caused by the long distance connection to Key Server for each new coming end-user request. The performance improvements using persistent session and key caching onto cloud will degrade the key invulnerability and discourage the website owners because of the cloud's security bugs. In this paper, the challenges of secured key protection and distribution are addressed in philosophy of "Storing the trusted DATA on untrusted platform and transmitting through untrusted channel". To this end, a three-phase hierarchical key management scheme, called STYX1 is proposed to provide the secured key protection together with hardware assisted service acceleration for cloud-based content delivery network (CCDN) applications. The STYX is implemented based on Intel Software Guard Extensions (SGX), Intel QuickAssist Technology (QAT) and SIGMA (SIGn-and-MAc) protocol. STYX can provide the tight key security guarantee by SGX based key distribution with a light overhead, and it can further significantly enhance the system performance with QAT based acceleration. The comprehensive evaluations show that the STYX not only guarantees the absolute security but also outperforms the direct HTTPS server deployed CDN without QAT by up to 5x throughput with significant latency reduction at the same time.

Cryptography and encryption is a topic that is blurred by its complexity making it difficult for the majority of the public to easily grasp. The focus of our research is based on SSL technology involving CAs, a centralized system that manages and issues certificates to web servers and computers for validation of identity. We first explain how the certificate provides a secure connection creating a trust between two parties looking to communicate with one another over the internet. Then the paper goes into what happens when trust is compromised and how information that is being transmitted could possibly go into the hands of the wrong person. We are proposing a browser plugin, Certificate Authority Rescue Engine (CAre), to serve as an added source of security with simplicity and visibility. In order to see why CAre will be an added benefit to average and technical users of the internet, one must understand what website security entails. Therefore, this paper will dive deep into website security through the use of public key infrastructure and its core components; certificates, certificate authorities, and their relationship with web browsers.

Encryption is critical in protecting the confidentiality of users' data on mobile devices. However, research has shown that many mobile apps are not correctly using the ciphers, which makes them vulnerable to the attacks. The existing resources on cipher programming education do not provide enough practical scenarios to help students learn the cipher programming in the context of real world situations with programs that have complex interacting modules with access to networking, storage, and database. This poster introduces a course module that teaches students how to develop secure Android applications by correctly using Android's cryptography APIs. This course module is targeted to two areas where programmers commonly make many mistakes: password based encryption and SSL certificate validation. The core of the module includes a real world sample Android program for students to secure by implementing cryptographic components correctly. The course module will use open-ended problem solving to let students freely explore the multiple options in securing the application. The course module includes a lecture slide on Android's Crypto library, its common misuses, and suggested good practices. Assessment materials will also be included in the course module. This course module will be used and evaluated in a Network Security class. We will present the results of the evaluation in the conference.

TLS has the potential to provide strong protection against network-based attackers and mass surveillance, but many implementations take security shortcuts in order to reduce the costs of cryptographic computations and network round trips. We report the results of a nine-week study that measures the use and security impact of these shortcuts for HTTPS sites among Alexa Top Million domains. We find widespread deployment of DHE and ECDHE private value reuse, TLS session resumption, and TLS session tickets. These practices greatly reduce the protection afforded by forward secrecy: connections to 38% of Top Million HTTPS sites are vulnerable to decryption if the server is compromised up to 24 hours later, and 10% up to 30 days later, regardless of the selected cipher suite. We also investigate the practice of TLS secrets and session state being shared across domains, finding that in some cases, the theft of a single secret value can compromise connections to tens of thousands of sites. These results suggest that site operators need to better understand the tradeoffs between optimizing TLS performance and providing strong security, particularly when faced with nation-state attackers with a history of aggressive, large-scale surveillance.