CRC-32 forging

You may already know that the CRC-32 of any text can be forged if you can add 4 bytes anywhere in the text. See anarchriz's paper on the subject.

A real-world example of such a situation can be seen in JB's ESET CONFidence Crackme Writeup. Good code that I recently used it in another situation, in order to forge a text of a given CRC-32 by inserting 4 bytes at a specific position.