Make your data for instance....'it will crash to $40 on Sunday. Xr898912' with the rubbish at the end so it's not easy to reverse.
When you post the hash output, we can verify it on Sunday when you post 'it will crash to $40 on Sunday. Xr898912' by doing the same as you done and comparing the output to the one you post today.
Make sense?
Lets make a test with gibberish data:
1. Let's assume that I post this hash:
63978b5bbe593d9a79813b4decabb35120747623693d89cbffb4c0156610bdfb
2. Am I correct to assume that when I am comfortable I will simply post the content of the pre-hashed data and you will simply compare the pre-hashed data with hash? What service will you use to compare?