Yes, ED25519 is compatible with keytool -genkey (or -genkeypair) on Linux, but only if you are using a recent version of Java (JDK 15 or later). Starting with JDK 15, Java's keytool supports the EdDSA algorithm, which includes ED25519. You can specify -keyalg EdDSA or directly -keyalg Ed25519 to generate an ED25519 key pairdocs.oracle.com+2.

However, LineageOS 23.2 is based on Android 13, and the version of Java (or the Android SDK's keytool) used in Android builds may not always support ED25519 for all use cases, especially for signing APKs or keystores. The Android build system traditionally relies on RSA or EC (ECDSA) for signing, and ED25519 support may not be guaranteed in all contexts within the Android toolchain.

Summary:

• On a standard Linux system with a recent JDK (15+), keytool -genkeypair -keyalg Ed25519 works.
• For LineageOS 23.2, check if the build environment's keytool (or the Android SDK's version) supports ED25519. If not, you may need to use RSA or ECDSA instead.

Would you like help checking the specific keytool version or testing ED25519 support in your LineageOS build environment?