By all probabilities, you might be using a Wi-Fi enabled router in your home. The primary function of this device is to convert the input signals (i.e. the internet) into wireless signals receivable on portable devices including mobile phones and laptops. Now, it is necessary to encrypt these signals coming from the router; else, someone in the vicinity might try to eavesdrop into your internet connection and misuse it. Here is the deal with WEP encryption. This is a secure encrypted format, which is hard to crack. WEP encryption is complete with the generation of an appropriate key.
If you are finding it hard to come up with WEP keys, then it is better to use a key generator for the same purpose. The WEP key generator can create 64, 128, 152 and 256-bit keys. Depending upon the bit rate, the WEP keys are hard to crack. Please ensure that your router supports the necessary keys before trying to use them.