Randy Dunlap reported build break:
ERROR: "crypto_alloc_shash" [lib/digsig.ko] undefined!
ERROR: "crypto_shash_final" [lib/digsig.ko] undefined!
ERROR: "crypto_shash_update" [lib/digsig.ko] undefined!
ERROR: "crypto_destroy_tfm" [lib/digsig.ko] undefined!
Added CRYPTO dependency and selected SHA1 algorithm.
Reported-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: James Morris <jmorris@namei.org>
 
 config SIGNATURE
        tristate "In-kernel signature checker"
-       depends on KEYS
+       depends on KEYS && CRYPTO
+       select CRYPTO_SHA1
        select MPILIB
        help
          Digital signature verification. Currently only RSA is supported.