Are there any SIM card providers in the US or Europe that provide strong identification on Phone number porting? Such as requiring a password or physical identification?
Many do, until an employee decides the number needs to be ported anyway. There is always an "override" feature / method to overcome these measures.
Telecoms are thin margin business and every human check or technical security measure will be rejected until customers start leaving, mentioning a particular issue. Problems with porting, S7 weaknesses, number spoofing and other anoyances is that you will be hard pressed to find an alternative operator that actually protects for these risks simply because they cost money and in the end only few customers are willing to pay the 10% a month extra.
