diff options
Diffstat (limited to 'src/gsm/auth_core.c')
| -rw-r--r-- | src/gsm/auth_core.c | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/src/gsm/auth_core.c b/src/gsm/auth_core.c index 400708f9..f171ed49 100644 --- a/src/gsm/auth_core.c +++ b/src/gsm/auth_core.c @@ -236,4 +236,17 @@ const struct value_string osmo_sub_auth_type_names[] = { { 0, NULL } }; +/* Derive GSM AKA ciphering key Kc from UMTS AKA CK and IK (auth function c3 from 3GPP TS 33.103 ยง + * 4.6.1). + * \param[out] kc GSM AKA Kc, 8 byte target buffer. + * \param[in] ck UMTS AKA CK, 16 byte input buffer. + * \param[in] ik UMTS AKA IK, 16 byte input buffer. + */ +void osmo_auth_c3(uint8_t kc[], const uint8_t ck[], const uint8_t ik[]) +{ + int i; + for (i = 0; i < 8; i++) + kc[i] = ck[i] ^ ck[i + 8] ^ ik[i] ^ ik[i + 8]; +} + /*! @} */ |