1# 2# Key management configuration 3# 4 5config KEYS 6 bool "Enable access key retention support" 7 select ASSOCIATIVE_ARRAY 8 help 9 This option provides support for retaining authentication tokens and 10 access keys in the kernel. 11 12 It also includes provision of methods by which such keys might be 13 associated with a process so that network filesystems, encryption 14 support and the like can find them. 15 16 Furthermore, a special type of key is available that acts as keyring: 17 a searchable sequence of keys. Each process is equipped with access 18 to five standard keyrings: UID-specific, GID-specific, session, 19 process and thread. 20 21 If you are unsure as to whether this is required, answer N. 22 23config PERSISTENT_KEYRINGS 24 bool "Enable register of persistent per-UID keyrings" 25 depends on KEYS 26 help 27 This option provides a register of persistent per-UID keyrings, 28 primarily aimed at Kerberos key storage. The keyrings are persistent 29 in the sense that they stay around after all processes of that UID 30 have exited, not that they survive the machine being rebooted. 31 32 A particular keyring may be accessed by either the user whose keyring 33 it is or by a process with administrative privileges. The active 34 LSMs gets to rule on which admin-level processes get to access the 35 cache. 36 37 Keyrings are created and added into the register upon demand and get 38 removed if they expire (a default timeout is set upon creation). 39 40config BIG_KEYS 41 bool "Large payload keys" 42 depends on KEYS 43 depends on TMPFS 44 select CRYPTO 45 select CRYPTO_AES 46 select CRYPTO_ECB 47 select CRYPTO_RNG 48 help 49 This option provides support for holding large keys within the kernel 50 (for example Kerberos ticket caches). The data may be stored out to 51 swapspace by tmpfs. 52 53 If you are unsure as to whether this is required, answer N. 54 55config TRUSTED_KEYS 56 tristate "TRUSTED KEYS" 57 depends on KEYS && TCG_TPM 58 select CRYPTO 59 select CRYPTO_HMAC 60 select CRYPTO_SHA1 61 select CRYPTO_HASH_INFO 62 help 63 This option provides support for creating, sealing, and unsealing 64 keys in the kernel. Trusted keys are random number symmetric keys, 65 generated and RSA-sealed by the TPM. The TPM only unseals the keys, 66 if the boot PCRs and other criteria match. Userspace will only ever 67 see encrypted blobs. 68 69 If you are unsure as to whether this is required, answer N. 70 71config ENCRYPTED_KEYS 72 tristate "ENCRYPTED KEYS" 73 depends on KEYS 74 select CRYPTO 75 select CRYPTO_HMAC 76 select CRYPTO_AES 77 select CRYPTO_CBC 78 select CRYPTO_SHA256 79 select CRYPTO_RNG 80 help 81 This option provides support for create/encrypting/decrypting keys 82 in the kernel. Encrypted keys are kernel generated random numbers, 83 which are encrypted/decrypted with a 'master' symmetric key. The 84 'master' key can be either a trusted-key or user-key type. 85 Userspace only ever sees/stores encrypted blobs. 86 87 If you are unsure as to whether this is required, answer N. 88 89config KEY_DH_OPERATIONS 90 bool "Diffie-Hellman operations on retained keys" 91 depends on KEYS 92 select MPILIB 93 help 94 This option provides support for calculating Diffie-Hellman 95 public keys and shared secrets using values stored as keys 96 in the kernel. 97 98 If you are unsure as to whether this is required, answer N. 99