Mojibake
is the name for incorrect, unreadable characters shown when computer software fails to show text correctly. When using computers, text is encoded using a character encoding.  In transfer, each character is replaced by its position (or number) in the encoding. To display the character again, the position is again replaced by the character. When the original encoding is not specified, a different character may be used when the number is again replaced with the character for display. Unicode was introduced to solve this problem: UTF-8 is able to encode most common characters in 2 bytes.