Grey hat Grey hat The term "grey hat", alternatively spelled as "greyhat" or "gray hat", refers to a computer hacker or computer security expert who may sometimes violate laws or typical ethical standards, but does not have the malicious intent typical of a black hat hacker. The term began to be used in the late 1990s, derived from the concepts of "white hat" and "black hat" hackers. When a white hat hacker discovers a vulnerability, they will exploit it only with permission and not divulge its existence until it has been fixed, whereas the black hat will illegally exploit it and/or tell
Global Trade Item Number and GTIN-14s may be encoded in ITF-14 or GS1-128 barcodes. The choice of barcode will depend on the application; for example, items to be sold at a retail establishment could be marked with EAN-8, EAN-13, UPC-A or UPC-E barcodes. The EAN-8 code is an eight-digit barcode used usually for very small articles, such as chewing gum, where fitting a larger code onto the item would be difficult. Note: the equivalent UPC small format barcode, UPC-E, encodes a GTIN-12 with a special Company Prefix that allows for "zero suppression" of four zeros in the GTIN-12. The GS1 encoding and decoding rules