Senior Security Software Engineer

  • Los Angeles, CA, USA
  • Employees can work remotely
  • Full-time

Company Description

We started with a simple idea—that everyone should be able to accept credit cards—and we’ve been rethinking buying and selling ever since.

For sellers, we’re creating one cohesive service to run your entire business, from a register in your pocket to analytics on your laptop. For buyers, we’re making it faster to order from the businesses you love and more fun to pay your friends back.

Buying and selling sound like simple things—and they should be. Somewhere along the way, they got complicated. We’re working hard to make commerce easy for everyone.

Job Description

We work to guarantee the security of every transaction from dip and tap to receipt. Our ultimate goal is to ensure that there is no possible way to use Square insecurely. In the Mobile Security group, we work to fluidly interpret signals from what could be a compromised or hostile environment - the OS and app running our code. We build workflows, both human and machine, to swiftly judge the requests for privilege that come with those signals, and we hunt the malefactor where they work.

An example of this is our work to support and validate PIN-on-Glass, the ability of our apps to receive entry of a customer PIN after an EMV card dip into our reader. This is a hugely constrained and sensitive transaction, controlled previously entirely by the banking industry, into which we were not only able to introduce our low-cost, easy-access product, but to also influence the industry itself and its newest standards.

We look for security engineers who understand both security and the human cost of securing a digital border. We need people who recognize that a false positive is a frustrated customer, that an engineer’s investigations are a limited commodity, and that threats are not always what they seem. We cannot succeed without elegant and scalable tooling, which is what you will build.

You will:

  • Lead and contribute to projects that span the following:

    • Signals processing and secure operations on mobile devices

    • Security incident review

    • Information flow and efficiency modeling

    • Case management user interfaces and backends

    • Applied machine learning in security contexts

    • Native library development for Android and iOS apps

    • Utilize software protection technologies including obfuscation, tamper detection, and whitebox cryptography

 

Qualifications

You have:

  • 5+ years of industry experience

  • A background in software engineering with a deep passion for making all things efficient

  • Interest in working across multiple technical domains, including backend microservices and iOS/Android clients

  • Strong examples of secure and elegant software development on production systems

  • Demonstrated experience developing, deploying, and monitoring systems for managing and scaling security investigations, judgements, and actions

 

Additional Information

We’re working to build a more inclusive economy where our customers have equal access to opportunity, and we strive to live by these same values in building our workplace. Block is a proud equal opportunity employer. We work hard to evaluate all employees and job applicants consistently, without regard to race, color, religion, gender, national origin, age, disability, pregnancy, gender expression or identity, sexual orientation, citizenship, or any other legally protected class. 

We believe in being fair, and are committed to an inclusive interview experience, including providing reasonable accommodations to disabled applicants throughout the recruitment process. We encourage applicants to share any needed accommodations with their recruiter, who will treat these requests as confidentially as possible. Want to learn more about what we’re doing to build a workplace that is fair and square? Check out our I+D page

Additionally, we consider qualified applicants with criminal histories for employment on our team, and always assess candidates on an individualized basis.

Perks

We want you to be well and thrive. Our global benefits package includes:

  • Healthcare coverage
  • Retirement Plans
  • Employee Stock Purchase Program
  • Wellness perks
  • Paid parental leave
  • Paid time off
  • Learning and Development resources

Block, Inc. (NYSE: SQ) is a global technology company with a focus on financial services. Made up of Square, Cash App, Spiral, TIDAL, and TBD, we build tools to help more people access the economy. Square helps sellers run and grow their businesses with its integrated ecosystem of commerce solutions, business software, and banking services. With Cash App, anyone can easily send, spend, or invest their money in stocks or Bitcoin. Spiral (formerly Square Crypto) builds and funds free, open-source Bitcoin projects. Artists use TIDAL to help them succeed as entrepreneurs and connect more deeply with fans. TBD is building an open developer platform to make it easier to access Bitcoin and other blockchain technologies without having to go through an institution.

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