Use a safer algorithm, and limit the size of the hashed string.

Fix an issue reported by Sonar.

features/ftue/impl/src/main/kotlin/io/element/android/features/ftue/impl/migration/SharedPrefsMigrationScreenStore.kt

@@ -19,7 +19,7 @@ package io.element.android.features.ftue.impl.migration
 import android.content.SharedPreferences
 import androidx.core.content.edit
 import com.squareup.anvil.annotations.ContributesBinding
-import io.element.android.libraries.androidutils.hash.md5
+import io.element.android.libraries.androidutils.hash.hash
 import io.element.android.libraries.di.AppScope
 import io.element.android.libraries.di.DefaultPreferences
 import io.element.android.libraries.matrix.api.core.SessionId
@@ -49,7 +49,9 @@ class SharedPrefsMigrationScreenStore @Inject constructor(
     }
 
     private fun SessionId.toKey(): String {
-        return IS_MIGRATION_SCREEN_SHOWN_PREFIX + value.md5()
+        // Hash the sessionId to get ride of exotic char and take only the first 16 chars,
+        // The risk of collision is not high.
+        return IS_MIGRATION_SCREEN_SHOWN_PREFIX + value.hash().take(16)
     }
 
     companion object {

libraries/androidutils/src/main/kotlin/io/element/android/libraries/androidutils/hash/Hash.kt

@@ -20,10 +20,10 @@ import java.security.MessageDigest
 import java.util.Locale
 
 /**
- * Compute a Hash of a String, using md5 algorithm.
+ * Compute a Hash of a String, using SHA-512 algorithm.
  */
-fun String.md5() = try {
+fun String.hash() = try {
-    val digest = MessageDigest.getInstance("md5")
+    val digest = MessageDigest.getInstance("SHA-512")
     digest.update(toByteArray())
     digest.digest()
             .joinToString("") { String.format(Locale.ROOT, "%02X", it) }