Serious security risk when generating private keys using bad randomness

There is a serious security problem when generating bitcoin private keys and corresponding addresses using pseudorandom numbers.

To make sure your bitcoins are secure, you have to store them on an address that was created with truly random private key.
The private key is basically a big random number – what makes it secure is the fact that it’s hard to guess it, because there is a huge number of valid private keys. Chances that someone else runs into your private key are very small (they could be using all computers in the world for their whole life, and the chance to run into your private key would still be negligible). – The safest Bitcoin wallet generator..

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