text: If a block cipher or cryptographic hash function does not exhibit the avalanche effect to a significant degree , then it has poor randomization , and thus a cryptanalyst can make predictions about the input , being given only the output .
simplified: If a block cipher or cryptographic hash function does not exhibit the avalanche effect to a significant degree , then it has poor randomization , and thus a cryptanalyst can make forecasts about the input , if given only the output .