Input validation

In this lesson, we discuss trusted and untrusted data sources, as well as trust boundaries for an app.

In this lesson, we discuss how to use autofill and autocorrect in our app.

In this lesson, we discuss autofill hints and SMS one-time-code autofill.

In this activity, we practice securing autocompletion in our app.

In this lesson, we discuss special characters, escaped characters, string literals and raw strings in Kotlin.

In this lesson, we discuss incorporating Unicode characters in our strings.

In this activity, we practice using special characters.

In this lesson, we discuss what null values and null pointer exceptions are. We learn how to check for nulls and make variables nullable.

In this lesson, we learn how to use the Kotlin safe call operator.

In this lesson, we learn how to use the Kotlin not null operator.

In this lesson, we learn how to use the Kotlin Elvis operator.

In this lesson, we learn how to use the Kotlin safe cast/unsafe cast operators.

In this lesson, we learn what Kotlin smart cast is and how to use it.

In this activity, we implement what we have learned about null safety.

We continue our activity implementing null safety.

We conclude our activity implementing null safety.

In this lesson, we learn what string interpolation is and how to use it in our code.

In this activity, we implement string interpolation.

In this lesson, we examine format strings and how they can be manipulated in an attack.

In this lesson, we explore regular expressions.

We continue with our lesson on regular expressions.

In this activity, we practice using regular expressions.

We continue our practice with regular expressions.

In this activity, we use regular expressions to validate user input in our app.

In this lesson, we discuss input sanitization.

In this activity, we practice sanitizing input.

In this activity, we continue practicing input sanitization by clamping input to a range.

In this lesson, we learn how to use the Kotlin filter() and trim() functions to limit output.

In this activity, we practice using Kotlin filter() and trim().

In this lesson, we learn about cross-site scripting and cross-site request forgery attacks.

In this activity, we examine the impact a cross-site scripting attack on a website.

In this lesson, we learn what cross-app scripting is and how to protect against it.

In this activity, we protect our app from cross-app scripting.

In this lesson, we learn what code injection is and how to avoid it.

We continue our lesson on code injection by examining SQL injection, directory traversal and poison null bytes.

We conclude our lesson on code injection by learning how to replace unsafe characters, identify scripting in HTML and examining the risks associated with QR codes.

In this activity, we protect a QR code reader from malicious input.

We conclude our activity of protecting our QR code reader app.

In this lesson, we learn about SQL injection and how to protect our app from it.

In this lesson, we learn about SQL stored procedures and how they can be used to protect against SQL injection.

In this lesson, we learn what object serialization/deserialization is and how it can pose security risks for our app.

We continue with our discussion of object deserialization, how to protect against it and how to use Google Gson to parse JSON objects.

In this activity, we use an API key to protect JSON input.

We continue with our activity of using an API key to protect JSON.

In this lesson, we learn how to use regex to validate form input.

We continue with our form validation discussion, using regex to validate email addresses.

We conclude our form validation lesson, learning how to validate passwords and phone numbers with regex. We also learn how to use Android built-in patterns to validate form input.

In this lesson, we learn about Android WebView and how to protect our app from SSL errors.

We continue our exploration of WebView, including protecting against malicious JavaScript. We are also introduced to Google Safe Browsing.

In this activity, we practice protecting our WebView app.

We continue our activity of validating form input.