This switches FastRandomContext to use a ChaCha20-based random number generator. It also makes the class richer by adding support for getting single bits of entropy.
Benchmarks (also added) show that rand32 became around 5.25x slower on my machine (from 1.5ns to 8ns), but the new randbool is 15% faster than the old one (1.3ns).
src/addrman.cpp: nKBucket = (nKBucket + insecure_rand.rand32()) % ADDRMAN_TRIED_BUCKET_COUNT; src/addrman.cpp: nKBucketPos = (nKBucketPos + insecure_rand.rand32()) % ADDRMAN_BUCKET_SIZE; src/addrman.cpp: nUBucket = (nUBucket + insecure_rand.rand32()) % ADDRMAN_NEW_BUCKET_COUNT; src/addrman.cpp: nUBucketPos = (nUBucketPos + insecure_rand.rand32()) % ADDRMAN_BUCKET_SIZE; src/bench/checkqueue.cpp: p.resize(insecure_rand.rand32() % (PREVECTOR_SIZE*2)); src/net.h: vAddrToSend[insecure_rand.rand32() % vAddrToSend.size()] = _addr;
Usage wants a randrange a lot more than a rand32
439@@ -439,4 +440,29 @@ BOOST_AUTO_TEST_CASE(aes_cbc_testvectors) {
440 "b2eb05e2c39be9fcda6c19078c6a9d1b3f461796d6b0d6b2e0c2a72b4d80e644");
441 }
442
443+BOOST_AUTO_TEST_CASE(chacha20_testvector)
randrange and the test vectors @jonasschnelli suggested.
182@@ -183,11 +183,8 @@ class prevector_tester {
183 }
184
185 ~prevector_tester() {
186- BOOST_CHECK_MESSAGE(passed, "insecure_rand_Rz: "
532@@ -533,6 +533,9 @@ AC_CHECK_DECLS([bswap_16, bswap_32, bswap_64],,,
533 #include <byteswap.h>
534 #endif])
535
536+AC_MSG_CHECKING(for __builtin_clzl)
34@@ -35,6 +35,7 @@ void GetStrongRandBytes(unsigned char* buf, int num);
35 */
36 class FastRandomContext {
37 private:
38+ bool requires_seed;
80@@ -81,6 +81,16 @@ class FastRandomContext {
81 }
82 }
83
84+ unsigned long randrange(unsigned long range)
85+ {
86+ --range;
87+ int bits = 8 * sizeof(long) - __builtin_clzl(range);
89@@ -89,6 +90,16 @@ class FastRandomContext {
90 }
91 }
92
93+ uint64_t randrange(uint64_t range)