Source: https://www.etsi.org/deliver/etsi_ts/133100_133199/133102/11.05.01_60/ts_133102v110501p.pdf
Section: 3.2
Generating 5G Authentication Vectors
This code generates magma 5g authentication vectors such as RAND, XRES*, AUTN, and Kseaf key using different parameters.
Code SS:
Generating SQN
SQN is derived by adding some SEQ(Sequence Number) and IND(Index) Values.
Source: https://www.etsi.org/deliver/etsi_ts/133100_133199/133102/11.05.01_60/ts_133102v110501p.pdf
Section: C.1.1.1, C.1.1.2, C.1.2, C.3.2
Code SS:
Source: https://github.com/magma/magma/blob/master/lte/gateway/python/magma/subscriberdb/processor.py#L323
Generating RAND
Code SS:
Generating OPc
OPc(Derived operator code unique for each SIM) is derived from OP(Operator Code) and K(Secret Key). OP and K are first encrypted using AES-128 Encryption Algorithm in CBC(Cipher block Chaining) Mode and then the output(opc) and the OP are taken as input into the XOR function to derive OPc.
Source: https://www.etsi.org/deliver/etsi_ts/135200_135299/135206/09.00.00_60/ts_135206v090000p.pdf
Section: 2.3
Code SS:
Generating MAC-A and MAC-S
MAC-A(Network Authentication Code) and MAC-S(Resynchronisation Authentication Code) are generated from Secret Key, SQN, RAND, OPc, and AMF using f1 and f1* cryptographic implementations through a single f1 function.
Source: https://www.etsi.org/deliver/etsi_ts/135200_135299/135206/09.00.00_60/ts_135206v090000p.pdf
Section 2.3
Code SS:
Generating XRES and AK
The XRES(Expected Response), and AK(Anonymity Key) are derived from RAND, OPc, and K using f2 and f5(or f5*) cryptography functions respectively. As the same inputs are used for deriving both parameters, a single operation is constructed for their implementation.
Source: https://www.etsi.org/deliver/etsi_ts/135200_135299/135206/09.00.00_60/ts_135206v090000p.pdf
Section 2.3
Code SS:
Generating CK
CK(Ciphering Key) is derived from the Secret Key(K), RAND, and OPc using the f3 cryptography function.
Code SS:
Generating IK
IK(Integrity Key) is derived from the Secret Key(K), RAND, and OPc using the f4 cryptography function.
Code SS:
Generating AUTN
An Authentication Token(AUTN) is generated from the SQN, AK, MAC-A, and AMF. SQN and AK are inserted into the XOR function and the output is combined with the AMF and MAC-A.
Code SS:
Generating XRES*
XRES* is generated from CK, IK, SNNi(Serving Network Name Identity), RAND, and XRES. First, a key is obtained by combining CK and IK then SNNi, RAND, and XRES length are converted into an array of bytes of size 2 with the first element stored as MSB(Most Significant Bit). Outputs from these operations are stored independently in different variables which are further combined with FC(it contains a byte object which is obtained from converting a hexadecimal string 6B) to form another new variable ‘S’.
Then, S and key are inserted as input into the HMAC-SHA-256 algorithm to obtain XRES*.
Source: https://www.etsi.org/deliver/etsi_ts/133500_133599/133501/16.03.00_60/ts_133501v160300p.pdf
Section: A.4
Source: https://www.etsi.org/deliver/etsi_ts/133200_133299/133220/14.01.00_60/ts_133220v140100p.pdf
Section: B.2.0
Code SS:
Source: https://github.com/blackberry/Python/blob/master/Python-3/Lib/hmac.py#L118
Generating Kausf Key
CK, IK, SNNi, and AUTN are encrypted in such a way as to form Kausf(AUSF Key). Alike XRES*, a key obtained from combining CK and Ik and stored into a variable k. Then, SNNi and RAND lengths are stored in an array of bytes using a python library. Then, these outputs are combined with FC(it contains a byte object which is obtained from converting a hexadecimal string 6A) to form another temporary string variable ‘S’.
S and k are hashed using KDF hashing algorithm HMAC-SHA-256 to form Kausf.
Source: https://www.etsi.org/deliver/etsi_ts/133500_133599/133501/16.03.00_60/ts_133501v160300p.pdf
Section: A.2
Code SS:
Source: https://github.com/blackberry/Python/blob/master/Python-3/Lib/hmac.py#L118
Generating Kseaf Key
Kseaf(SEAF Key) is obtained by integrating Kausf and SNNi through a hashing algorithm. In this derivation, Kausf acts as key(k) whereas SNNi is still disintegrated into 2 forms, one stores the value, and the other stores the length of the SNNi in an array of bytes of size 2. The resultant output is assembled with the FC(it contains a byte object which is obtained from converting a hexadecimal string 6C) and stored in variable ‘S’.
Then, S and key(Kausf) undergo the HMAC-SHA-256 hashing algorithm to generate Kseaf.
Source: https://www.etsi.org/deliver/etsi_ts/133500_133599/133501/16.03.00_60/ts_133501v160300p.pdf
Section: A.6
Code SS:
Source: https://github.com/blackberry/Python/blob/master/Python-3/Lib/hmac.py#L118