Accidental information revealed with an odd number of records and unhashed leaves

[amidmm]

In the case the tree is configured without hashing the leaves an odd number of records, there is a chance of unwanted information leakage through providing the proof.

Example

input:

  [
    "0x10",
    "0x20",
    "0x30",
    "0x40",
    "0x50"
  ]

The tree would be formed like the following:

└─ 5493d426be69128c5b6519e81d40789fdf00315e201f89f3145fe2fd790cf016
   ├─ 50
   │  └─ 50
   │     └─ 50
   └─ 52e9510c9a9b4b27dc47dcebf0bd2e6e728afeb986cbb84cde1adb1cc245342d
      ├─ 3c274a8322731c85c4d7f7d35a8b13cbab3a57a14170cce898055f9744e66124
      │  ├─ 10
      │  └─ 20
      └─ b6b0b94b1eeca3d159f819eb437760159b7bac423d25f7b21201130423635e99
         ├─ 30
         └─ 40

Will providing proof for any leaf would result in revealing 0x50.
Proof for 0x10:

[
  "0x20",
  "0xb6b0b94b1eeca3d159f819eb437760159b7bac423d25f7b21201130423635e99",
  "0x50"
]

Possible solution

Hash the odds by default instead of duplicating the odds