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authorSteffen Jaeckel <s_jaeckel@gmx.de>2019-09-16 15:50:38 +0200
committerMatt Johnston <matt@ucc.asn.au>2019-09-16 21:50:38 +0800
commit615ed4e46a52b6bfe0bfc581b8c2fbcc6cc488d1 (patch)
tree12b2ba29ae4c42fc65d64d43968c5d03ab3f4452 /libtommath/bn_mp_get_bit.c
parentfa116e983b4931010e1082dd5c8bf38bbc77718c (diff)
update ltm to 1.1.0 and enable FIPS 186.4 compliant key-generation (#79)
* make key-generation compliant to FIPS 186.4 * fix includes in tommath_class.h * update fuzzcorpus instead of error-out * fixup fuzzing make-targets * update Makefile.in * apply necessary patches to ltm sources * clean-up not required ltm files * update to vanilla ltm 1.1.0 this already only contains the required files * remove set/get double
Diffstat (limited to 'libtommath/bn_mp_get_bit.c')
-rw-r--r--libtommath/bn_mp_get_bit.c54
1 files changed, 54 insertions, 0 deletions
diff --git a/libtommath/bn_mp_get_bit.c b/libtommath/bn_mp_get_bit.c
new file mode 100644
index 0000000..fc2d76e
--- /dev/null
+++ b/libtommath/bn_mp_get_bit.c
@@ -0,0 +1,54 @@
+#include "tommath_private.h"
+#ifdef BN_MP_GET_BIT_C
+
+/* LibTomMath, multiple-precision integer library -- Tom St Denis
+ *
+ * LibTomMath is a library that provides multiple-precision
+ * integer arithmetic as well as number theoretic functionality.
+ *
+ * The library was designed directly after the MPI library by
+ * Michael Fromberger but has been written from scratch with
+ * additional optimizations in place.
+ *
+ * SPDX-License-Identifier: Unlicense
+ */
+
+/* Checks the bit at position b and returns MP_YES
+ if the bit is 1, MP_NO if it is 0 and MP_VAL
+ in case of error */
+int mp_get_bit(const mp_int *a, int b)
+{
+ int limb;
+ mp_digit bit, isset;
+
+ if (b < 0) {
+ return MP_VAL;
+ }
+
+ limb = b / DIGIT_BIT;
+
+ /*
+ * Zero is a special value with the member "used" set to zero.
+ * Needs to be tested before the check for the upper boundary
+ * otherwise (limb >= a->used) would be true for a = 0
+ */
+
+ if (mp_iszero(a) != MP_NO) {
+ return MP_NO;
+ }
+
+ if (limb >= a->used) {
+ return MP_VAL;
+ }
+
+ bit = (mp_digit)(1) << (b % DIGIT_BIT);
+
+ isset = a->dp[limb] & bit;
+ return (isset != 0u) ? MP_YES : MP_NO;
+}
+
+#endif
+
+/* ref: HEAD -> master, tag: v1.1.0 */
+/* git commit: 08549ad6bc8b0cede0b357a9c341c5c6473a9c55 */
+/* commit time: 2019-01-28 20:32:32 +0100 */