A method for storing and updating digital certificates in a flash memory, a flash memory, and an electronic apparatus exploiting the method are disclosed. The method is applicable for a flash memory having predefined erase-write blocks and write-read blocks, for enhancing the tampering proof characteristics of the flash memory. The certificates may be used to authenticate a computer program and may be verified by a verification program associated with the computer program. The method may include defining a plurality of memory slots within at least one erased erase-write block wherein each memory slot have a commencing address comprising a binary “0”- or a binary “1” bit pattern, writing a first and second digital certificate in a first and second one of the memory slots, defining a certificate slot address pointer, and updating the certificate slot address pointer by replacing said “0”- or “1”-bit pattern of the pointer with a “1”- or a “0” bit pattern, respectively.