Bounty offered for anyone who can help me recover my ETH wallet private key

I wrote my private key down but I must have gotten one of the digits wrong. If someone can write a tool that helps me find it, I will pay you a bounty of 1 ETH.

Basically the key is 64 characters and each digit must fall within the range of 0 to F, so I need to try 64 * 16 variations replacing each digit with every other possible digit.

Please send me a message if you can help with this.