Cryptographic key issues and solutions for the bit sieve/pixel-sieve method

During the testing and analysis for robustness of pixel sieve and bit sieve cryptographic methods few weaknesses emerged. Some of them are related to the cryptographic key itself. Not any kind of key is secure to use for encryption. Some serious restrictions regarding the keys are reducing the number of usable keys in a given keys-pace. On one issue for a key length of n only n/3 keys are safe to use and those keys ar also subject for restrictions. Within this paper thees weaknesses will be shown among with some proposed solutions. The solutions found are using techniques like: key expansion, XORing, circular permutation and key shifting. With the solutions presented here some of the key related issues are solved increasing the robustness and security of the method.