I am developing a large application and i need encryption when a data is traveling between two machines in different continents. I have never worked on encryption. I want a simple encryption which can be handled in PHP / Ruby / Python without any dependencies.
So i decided to use HMAC SHA1.
$pad=hash_hmac("sha1","The quick brown....","mykey");
This is what i found out after some research on the internet.
How hard it is to decrypt it if someone doesn't know the key? Also, any alternatives to this?
UPDATE - thanks for all the responses. Problem solved.
It's impossible to decrypt it, even if you know the key. HMAC SHA1 is a keyed hash algorithm, not encryption.
A hash is a cryptographic one-way function that always generates a value of the same length (I think SHA1 is 128-bits) regardless of the length of the input. The point of a hash is that, given the output value, it's computationally infeasible to find an input value to produce that output. A keyed hash is used to prevent rainbow table attacks. Even if you know the key you can't reverse the hash process.
For encryption you want to look at AES.