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authorlloyd <[email protected]>2008-09-30 22:41:49 +0000
committerlloyd <[email protected]>2008-09-30 22:41:49 +0000
commit13d08cbe978c4cd0de01aa0120c39470508cbbcb (patch)
treeff93739131cbca0dbdf23a31cd4b7611faf5aa6e /src/math/bigint/big_rand.cpp
parent8854fe339f2e1f81091ba65c042824e8cc62cbbc (diff)
Rearrange BigInt directories:
math/bigint - BigInt implementation math/numbertheory - Math stuff built on top of BigInt Coming soon: math/gfp (parts of pk/ecdsa) Update deps in the pk files
Diffstat (limited to 'src/math/bigint/big_rand.cpp')
-rw-r--r--src/math/bigint/big_rand.cpp59
1 files changed, 59 insertions, 0 deletions
diff --git a/src/math/bigint/big_rand.cpp b/src/math/bigint/big_rand.cpp
new file mode 100644
index 000000000..055873642
--- /dev/null
+++ b/src/math/bigint/big_rand.cpp
@@ -0,0 +1,59 @@
+/*************************************************
+* BigInt Random Generation Source File *
+* (C) 1999-2007 Jack Lloyd *
+*************************************************/
+
+#include <botan/bigint.h>
+#include <botan/parsing.h>
+
+namespace Botan {
+
+/*************************************************
+* Construct a BigInt of a specific form *
+*************************************************/
+BigInt::BigInt(NumberType type, u32bit bits)
+ {
+ set_sign(Positive);
+
+ if(type == Power2)
+ set_bit(bits);
+ else
+ throw Invalid_Argument("BigInt(NumberType): Unknown type");
+ }
+
+/*************************************************
+* Randomize this number *
+*************************************************/
+void BigInt::randomize(RandomNumberGenerator& rng,
+ u32bit bitsize)
+ {
+ set_sign(Positive);
+
+ if(bitsize == 0)
+ clear();
+ else
+ {
+ SecureVector<byte> array((bitsize + 7) / 8);
+ rng.randomize(array, array.size());
+ if(bitsize % 8)
+ array[0] &= 0xFF >> (8 - (bitsize % 8));
+ array[0] |= 0x80 >> ((bitsize % 8) ? (8 - bitsize % 8) : 0);
+ binary_decode(array, array.size());
+ }
+ }
+
+/*************************************************
+* Generate a random integer within given range *
+*************************************************/
+BigInt BigInt::random_integer(RandomNumberGenerator& rng,
+ const BigInt& min, const BigInt& max)
+ {
+ BigInt range = max - min;
+
+ if(range <= 0)
+ throw Invalid_Argument("random_integer: invalid min/max values");
+
+ return (min + (BigInt(rng, range.bits() + 2) % range));
+ }
+
+}