EUIMID (expanded UIMID) is a unique identifier for an R-UIM (Removable User Identity Module) or CSIM (CDMA SIM application) card in CDMA2000 cellular systems that replaces the older UIMID identifier. There are two forms of EUIMID, known as Short Form (SF_EUIMID) and Long Form (LF_EUIMID). Both produce a 32-bit pseudo-UIMID (pUIMID) with 0x80 in the upper 8 bits and the least significant 24 bits of the SHA-1 hash of the entire SF_EUIMID or the entire ICCID EF (for LF_EUIMID) in the lower 24 bits.
The EUIMID (and UIMID) are hardware identifiers that do not change throughout the life of the card they identify. Their most important characteristic is that they are globally unique, no two R-UIM or CSIM cards should ever be given the same number. Secondly, they can identify the issuer of the code (likely a mobile phone operator in the case of LF_EUIMID, and an R-UIM or CSIM card manufacturer in the case of SF_EUIMID). The pseudo-UIMID is not unique, but can satisfy most uses of UIMID. Where this is not possible, or not desirable, another unique identifier (such as EUIMID) should be used instead or the requirement for uniqueness should be removed.