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authorBen Summers <ben@fluffy.co.uk>2005-10-14 08:50:54 +0000
committerBen Summers <ben@fluffy.co.uk>2005-10-14 08:50:54 +0000
commit99f8ce096bc5569adbfea1911dbcda24c28d8d8b (patch)
tree049c302161fea1f2f6223e1e8f3c40d9e8aadc8b /lib/crypto/Random.cpp
Box Backup 0.09 with a few tweeks
Diffstat (limited to 'lib/crypto/Random.cpp')
-rwxr-xr-xlib/crypto/Random.cpp127
1 files changed, 127 insertions, 0 deletions
diff --git a/lib/crypto/Random.cpp b/lib/crypto/Random.cpp
new file mode 100755
index 00000000..3df5fc5e
--- /dev/null
+++ b/lib/crypto/Random.cpp
@@ -0,0 +1,127 @@
+// --------------------------------------------------------------------------
+//
+// File
+// Name: Random.cpp
+// Purpose: Random numbers
+// Created: 31/12/03
+//
+// --------------------------------------------------------------------------
+
+#include "Box.h"
+
+#include <openssl/rand.h>
+#include <stdio.h>
+
+#include "Random.h"
+#include "CipherException.h"
+
+#include "MemLeakFindOn.h"
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+// Name: Random::Initialise()
+// Purpose: Add additional randomness to the standard library initialisation
+// Created: 18/6/04
+//
+// --------------------------------------------------------------------------
+void Random::Initialise()
+{
+#ifndef PLATFORM_RANDOM_DEVICE_NONE
+ if(::RAND_load_file(PLATFORM_RANDOM_DEVICE, 1024) != 1024)
+ {
+ THROW_EXCEPTION(CipherException, RandomInitFailed)
+ }
+#else
+ ::fprintf(stderr, "No random device -- additional seeding of random number generator not performed.\n");
+#endif
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+// Name: Random::Generate(void *, int)
+// Purpose: Generate Length bytes of random data
+// Created: 31/12/03
+//
+// --------------------------------------------------------------------------
+void Random::Generate(void *pOutput, int Length)
+{
+ if(RAND_pseudo_bytes((uint8_t*)pOutput, Length) == -1)
+ {
+ THROW_EXCEPTION(CipherException, PseudoRandNotAvailable)
+ }
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+// Name: Random::GenerateHex(int)
+// Purpose: Generate Length bytes of hex encoded data. Note that the
+// maximum length requested is limited. (Returns a string
+// 2 x Length characters long.)
+// Created: 1/11/04
+//
+// --------------------------------------------------------------------------
+std::string Random::GenerateHex(int Length)
+{
+ uint8_t r[256];
+ if(Length > sizeof(r))
+ {
+ THROW_EXCEPTION(CipherException, LengthRequestedTooLongForRandomHex)
+ }
+ Random::Generate(r, Length);
+
+ std::string o;
+ static const char *h = "0123456789abcdef";
+ for(int l = 0; l < Length; ++l)
+ {
+ o += h[r[l] >> 4];
+ o += h[r[l] & 0xf];
+ }
+
+ return o;
+}
+
+
+// --------------------------------------------------------------------------
+//
+// Function
+// Name: Random::RandomInt(int)
+// Purpose: Return a random integer between 0 and MaxValue inclusive.
+// Created: 21/1/04
+//
+// --------------------------------------------------------------------------
+uint32_t Random::RandomInt(uint32_t MaxValue)
+{
+ uint32_t v = 0;
+
+ // Generate a mask
+ uint32_t mask = 0;
+ while(mask < MaxValue)
+ {
+ mask = (mask << 1) | 1;
+ }
+
+ do
+ {
+ // Generate a random number
+ uint32_t r = 0;
+ Random::Generate(&r, sizeof(r));
+
+ // Mask off relevant bits
+ v = r & mask;
+
+ // Check that it's in the right range.
+ } while(v > MaxValue);
+
+ // NOTE: don't do a mod, because this doesn't give a correct random distribution
+
+ return v;
+}
+
+
+