client: add preimage doc

ethereumjs · Mar 1, 2024 · 1c413fa · 1c413fa
1 parent 0e589de
commit 1c413fa
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/packages/client/src/execution/preimage.ts b/packages/client/src/execution/preimage.ts
@@ -1,5 +1,11 @@
 import { DBKey, MetaDBManager } from '../util/metaDBManager'
 
+/**
+ * The `PreImagesManager` saves the preimages of hashed keys. This is necessary for the Verkle transition.
+ * A "PreImage" of a hash is whatever the input is to the hashed function. So, if one calls `keccak256(X)` with
+ * output `Y` then `X` is the preimage of `Y`. It thus serves to recover the input to the trapdoor hash function,
+ * which would otherwise not be feasible.
+ */
 export class PreimagesManager extends MetaDBManager {
   /**
    * Returns the preimage for a given hashed key