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2015-05-28crypto: jitterentropy - remove timekeeping_valid_for_hresStephan Mueller1-3/+0
The patch removes the use of timekeeping_valid_for_hres which is now marked as internal for the time keeping subsystem. The jitterentropy does not really require this verification as a coarse timer (when random_get_entropy is absent) is discovered by the initialization test of jent_entropy_init, which would cause the jitter rng to not load in that case. Reported-by: kbuild test robot <fengguang.wu@intel.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
2015-05-27crypto: jitterentropy - add jitterentropy RNGStephan Mueller1-0/+909
The CPU Jitter RNG provides a source of good entropy by collecting CPU executing time jitter. The entropy in the CPU execution time jitter is magnified by the CPU Jitter Random Number Generator. The CPU Jitter Random Number Generator uses the CPU execution timing jitter to generate a bit stream which complies with different statistical measurements that determine the bit stream is random. The CPU Jitter Random Number Generator delivers entropy which follows information theoretical requirements. Based on these studies and the implementation, the caller can assume that one bit of data extracted from the CPU Jitter Random Number Generator holds one bit of entropy. The CPU Jitter Random Number Generator provides a decentralized source of entropy, i.e. every caller can operate on a private state of the entropy pool. The RNG does not have any dependencies on any other service in the kernel. The RNG only needs a high-resolution time stamp. Further design details, the cryptographic assessment and large array of test results are documented at http://www.chronox.de/jent.html. CC: Andreas Steffen <andreas.steffen@strongswan.org> CC: Theodore Ts'o <tytso@mit.edu> CC: Sandy Harris <sandyinchina@gmail.com> Signed-off-by: Stephan Mueller <smueller@chronox.de> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>