One of IDA Pro’s most important features is that it allows us to interactively modify the disassembly – hence, the I in IDA. This includes renaming of function names, variable names, and names of addresses. IDA Pro refers to these names as identifiers and enforces a certain naming scheme on them. After working with IDA Pro for a couple of weeks most people develop a good understanding of valid names and what to avoid when renaming identifiers. However, I wanted to know how IDA Pro checks identifiers and describe my findings in this blog post. In addition to this, I discuss the character encoding used for comments in IDA Pro. Adding comments to a disassembled program is another useful feature many reverse engineers take advantage of. While users normally don’t have to worry about the comment encoding this information can be handy in certain situations – especially when dealing with comments in IDAPython scripts.