I know that base91, as defined by Joachim Henke, uses these characters: ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789!#$%&()*+,./:;<=>?@[]^_`{|}~" What steps should one perform in order to convert strings to and from base91? Continue reading...