4.2.3 EFKeys (Ciphering and Integrity Keys)
31.1023GPPCharacteristics of the Universal Subscriber Identity Module (USIM) applicationRelease 17TS
This EF contains the ciphering key CK, the integrity key IK and the key set identifier KSI.
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Identifier: ‘6F08’ |
Structure: transparent |
Mandatory |
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SFI: ’08’ |
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File size: 33 bytes |
Update activity: high |
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Access Conditions: READ PIN UPDATE PIN DEACTIVATE ADM ACTIVATE ADM |
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Bytes |
Description |
M/O |
Length |
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1 |
Key set identifier KSI |
M |
1 byte |
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2 to 17 |
Ciphering key CK |
M |
16 bytes |
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18 to 33 |
Integrity key IK |
M |
16 bytes |
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– Key Set Identifier KSI.
Coding:
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b8 |
b7 |
b6 |
b5 |
b4 |
b3 |
b2 |
b1 |
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KSI |
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bits b4 to b8 are coded 0 |
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‑ Ciphering key CK.
Coding:
– the least significant bit of CK is the least significant bit of the 17th byte. The most significant bit of CK is the most significant bit of the 2nd byte.
‑ Integrity key IK.
Coding:
– the least significant bit of IK is the least significant bit of the 33rd byte. The most significant bit of IK is the most significant bit of the 18th byte.