SIM cloning is the process in which a legitimate SIM card is duplicated. When SIM cloning is completed, the cloned SIM card's identifying information is transferred onto a separate, secondary SIM card. The secondary card can then be used in a different phone while having all calls and associated charges attributed to the original SIM card. The phrase SIM clone is often used to refer to the SIM card that has been successfully duplicated.
A successful duplication hinges on the a user's ability to extract the SIM card's IMSI (International Mobile Subscriber Identifier) and Authentication key (Ki). While a IMSI is relatively easy to identify, finding the Ki can prove to be much more difficult for the novice user. Separate devices and software programs may have to be used to decrypt the Ki.
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