updated documentation of hash preimage generation

1 files changed, 8 insertions, 6 deletions

diff --git a/documentation/README.md b/documentation/README.md
index ca08eef..f507ecc 100644
--- a/documentation/README.md
+++ b/documentation/README.md
@@ -206,12 +206,14 @@ can now list the hashes of all registered users.
 The next step is to find a valid preimage for the hashes obtained
 previously, to log in as them and query information about their files.
 
-To calculate the preimage we choose a seed for srand at random. Then
-we XOR the values encoded in the hex-encoded with calls to rand().
-If the sum of the generated values is greated than the seed we used,
-restart. Otherwise, append some characters to make the sum match
-the seed like it does in mhash. The value of these 'extra' chars
-is irrelevant, since mhash only processes the first 20 chars anyways.
+To calculate the preimage we repeatedly choose a seed for srand. For
+each seed, we XOR the values encoded in the hex-encoded hash with
+calls to rand(). If after generating each character the sum of the
+generated values is less than the seed we used, restart. Otherwise,
+we append some characters to make the sum of the input characters
+match the seed, such that the seed for srand mhash uses matches the
+one we chose. The actual value of these 'extra' chars is irrelevant,
+since mhash only processes the first 20 chars anyways.
 
 See `checker/src/revhash/main.c` for an example implementation in C.