KEYS: trusted: allow use of kernel RNG for key material

[linux-2.6-microblaze.git] / Documentation / security / keys / trusted-encrypted.rst

diff --git a/Documentation/security/keys/trusted-encrypted.rst b/Documentation/security/keys/trusted-encrypted.rst
index f614dad..2fe6fd1 100644 (file)
--- a/Documentation/security/keys/trusted-encrypted.rst
+++ b/Documentation/security/keys/trusted-encrypted.rst
@@ -87,22 +87,26 @@ Key Generation
 Trusted Keys
 ------------
 
-New keys are created from random numbers generated in the trust source. They
-are encrypted/decrypted using a child key in the storage key hierarchy.
-Encryption and decryption of the child key must be protected by a strong
-access control policy within the trust source.
+New keys are created from random numbers. They are encrypted/decrypted using
+a child key in the storage key hierarchy. Encryption and decryption of the
+child key must be protected by a strong access control policy within the
+trust source. The random number generator in use differs according to the
+selected trust source:
 
-  *  TPM (hardware device) based RNG
+  *  TPM: hardware device based RNG
 
-     Strength of random numbers may vary from one device manufacturer to
-     another.
+     Keys are generated within the TPM. Strength of random numbers may vary
+     from one device manufacturer to another.
 
-  *  TEE (OP-TEE based on Arm TrustZone) based RNG
+  *  TEE: OP-TEE based on Arm TrustZone based RNG
 
      RNG is customizable as per platform needs. It can either be direct output
      from platform specific hardware RNG or a software based Fortuna CSPRNG
      which can be seeded via multiple entropy sources.
 
+Users may override this by specifying ``trusted.rng=kernel`` on the kernel
+command-line to override the used RNG with the kernel's random number pool.
+
 Encrypted Keys
 --------------