18 PTC Encryption
33.1083G Security3GPPHandover interface for Lawful Interception (LI)Release 17TS
When a CSP has PTC services with Security options the CSP shall provide the encryption method, specific parameters, and the Security to decrypt to LEA when a service uses encryption that is provided or managed by the CSP.
Table 18.1: Encryption Parameters
|
Observed MSISDN |
M |
Provide at least one and others when available. |
|
Observed IMSI |
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|
Observed IMEI |
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Observed SIP URI |
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|
Observed TEL URI |
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Observed IPv4/IPv6 Address |
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Observed MCPPTID |
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|
PTCType |
M |
Shall indicate PTC Encryption event |
|
LawfulInterceptionIdentifier |
M |
Unique number for each surveillance lawful authorization. |
|
Event Date |
M |
Date of the event generation. |
|
Event Time |
Time of the event generation. |
|
|
CryptoContext |
C |
If further information is needed to associate the encryption information with a specific session or stream, this parameter shall identify the context to which this encryption message applies. |
|
Cipher |
M |
Shall include the name of the cipher. |
|
Key |
M |
Shall include the key needed to decipher. |
|
Salt |
C |
Shall include the initial salt value, if the cipher requires a salt value. |
|
KeyEncoding |
C |
Shall include the encoding of the key if the encoding is other than binary. |
|
PTCOther |
C |
Shall be included if other information is required to decrypt the data. |
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NOTE 1: LIID parameter shall be present in each record sent to the LEMF |
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The PTCEncryptionInfo Encryption message can be sent when there is a need to pass the decryption information associated with intercepted content. If rekeying is deployed, one or more new Encryption messages are sent coincident with the change in keys.
Table 18.2: Mapping between Events information and IRI information
|
Parameter |
Definition |
ASN.1 parameter |
|
Observed MSISDN |
Target Identifier with the MSISDN of the target. |
partyInformation (partyIdentity) |
|
Observed IMSI |
Target Identifier with the IMSI of the target. |
partyInformation (partyIdentity) |
|
Observed IMEI |
Target Identifier with the IMEI of the target. |
partyInformation (partyIdentity) |
|
Observed SIP URI |
Observed SIP URI. |
partyInformation (partyIdentity) |
|
Observed TEL URI |
Observed TEL URI. |
partyInformation (partyIdentity) |
|
Observed MCPTT ID |
Observed MCPTT Identity, if available. |
mCPTTID |
|
Event Type |
Description of which type of event is delivered: PTC Encryption Parameters. |
pTCEvent |
|
Event TIME Event Date |
Time and date of the event generation in the PTC Server or Client. |
timeStamp |
|
Crypto Context |
If further information is needed to associate the encryption information with a specific session or stream, this parameter shall be included to identify the context to which this encryption message applies. |
(PTCEncryptionInfo) cryptoContext |
|
Cipher |
The name of the cipher used |
(PTCEncryptionInfo) cipher |
|
Key |
The key needed to decipher. |
(PTCEncryptionInfo) key |
|
KeyEncoding |
Shall be included to provide the encoding of the key if the encoding is other than binary. |
(PTCEncryptionInfo) keyEncoding |
|
Salt |
Include to provide the initial salt value if the cipher requires a salt value. |
(PTCEncryptionInfo) salt |
|
PTCOther |
Other information that is required to decrypt the data. |
(PTCEncryptionInfo) pTCOther |
Annex A (normative):
HI2 delivery mechanisms and procedures