(#) Application uses vulnerable cryptography algorithms !!! ERROR: Application uses vulnerable cryptography algorithms This is an error. Id : `VulnerableCryptoAlgorithm` Summary : Application uses vulnerable cryptography algorithms Severity : Error Category : Security Platform : Any Vendor : Google - Android 3P Vulnerability Research Contact : https://github.com/google/android-security-lints Feedback : https://github.com/google/android-security-lints/issues Min : Lint 4.1 Compiled : Lint 8.0 and 8.1 Artifact : [com.android.security.lint:lint](com_android_security_lint_lint.md.html) Since : 1.0.1 Affects : Kotlin and Java files Editing : This check runs on the fly in the IDE editor See : https://goo.gle/VulnerableCryptoAlgorithm Implementation : [Source Code](https://github.com/google/android-security-lints/tree/main/checks/src/main/java/com/example/lint/checks/BadCryptographyUsageDetector.kt) Tests : [Source Code](https://github.com/google/android-security-lints/tree/main/checks/src/test/java/com/example/lint/checks/BadCryptographyUsageDetectorTest.kt) Copyright Year : 2023 Using weak or broken cryptographic hash functions may allow an attacker to reasonably determine the original input or produce multiple inputs with the same hash value. !!! Tip This lint check has an associated quickfix available in the IDE. (##) Example Here is an example of lint warnings produced by this check: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~text src/fake/pkg/TestBadCryptoDetector.java:8:Error: Using vulnerable cryptographic algorithms puts the original input at risk of discovery [VulnerableCryptoAlgorithm] Cipher.getInstance(algo); ------------------------ ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Here is the source file referenced above: `src/fake/pkg/TestBadCryptoDetector.java`: ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~java linenumbers package fake.pkg; import javax.crypto.Cipher; public class TestBadCryptoDetector { private void foo() { String algo = "RC2"; Cipher.getInstance(algo); } } ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ You can also visit the [source code](https://github.com/google/android-security-lints/tree/main/checks/src/test/java/com/example/lint/checks/BadCryptographyUsageDetectorTest.kt) for the unit tests for this check to see additional scenarios. The above example was automatically extracted from the first unit test found for this lint check, `BadCryptographyUsageDetector.testWhenVulnerableCryptoBlockAlgoUsed_showsErrorAndQuickFix`. To report a problem with this extracted sample, visit https://github.com/google/android-security-lints/issues. (##) Including !!! This is not a built-in check. To include it, add the below dependency to your project. This lint check is included in the lint documentation, but the Android team may or may not agree with its recommendations. ``` // build.gradle.kts lintChecks("com.android.security.lint:lint:1.0.3") // build.gradle lintChecks 'com.android.security.lint:lint:1.0.3' // build.gradle.kts with version catalogs: lintChecks(libs.com.android.security.lint.lint) # libs.versions.toml [versions] com-android-security-lint-lint = "1.0.3" [libraries] # For clarity and text wrapping purposes the following declaration is # shown split up across lines, but in TOML it needs to be on a single # line (see https://github.com/toml-lang/toml/issues/516) so adjust # when pasting into libs.versions.toml: com-android-security-lint-lint = { module = "com.android.security.lint:lint", version.ref = "com-android-security-lint-lint" } ``` 1.0.3 is the version this documentation was generated from; there may be newer versions available. [Additional details about com.android.security.lint:lint](com_android_security_lint_lint.md.html). (##) Suppressing You can suppress false positives using one of the following mechanisms: * Using a suppression annotation like this on the enclosing element: ```kt // Kotlin @Suppress("VulnerableCryptoAlgorithm") fun method() { getInstance(...) } ``` or ```java // Java @SuppressWarnings("VulnerableCryptoAlgorithm") void method() { getInstance(...); } ``` * Using a suppression comment like this on the line above: ```kt //noinspection VulnerableCryptoAlgorithm problematicStatement() ``` * Using a special `lint.xml` file in the source tree which turns off the check in that folder and any sub folder. A simple file might look like this: ```xml <?xml version="1.0" encoding="UTF-8"?> <lint> <issue id="VulnerableCryptoAlgorithm" severity="ignore" /> </lint> ``` Instead of `ignore` you can also change the severity here, for example from `error` to `warning`. You can find additional documentation on how to filter issues by path, regular expression and so on [here](https://googlesamples.github.io/android-custom-lint-rules/usage/lintxml.md.html). * In Gradle projects, using the DSL syntax to configure lint. For example, you can use something like ```gradle lintOptions { disable 'VulnerableCryptoAlgorithm' } ``` In Android projects this should be nested inside an `android { }` block. * For manual invocations of `lint`, using the `--ignore` flag: ``` $ lint --ignore VulnerableCryptoAlgorithm ...` ``` * Last, but not least, using baselines, as discussed [here](https://googlesamples.github.io/android-custom-lint-rules/usage/baselines.md.html).