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| author | S. Solomon Darnell | 2025-03-28 21:52:21 -0500 |
|---|---|---|
| committer | S. Solomon Darnell | 2025-03-28 21:52:21 -0500 |
| commit | 4a52a71956a8d46fcb7294ac71734504bb09bcc2 (patch) | |
| tree | ee3dc5af3b6313e921cd920906356f5d4febc4ed /.venv/lib/python3.12/site-packages/rsa/randnum.py | |
| parent | cc961e04ba734dd72309fb548a2f97d67d578813 (diff) | |
| download | gn-ai-master.tar.gz | |
Diffstat (limited to '.venv/lib/python3.12/site-packages/rsa/randnum.py')
| -rw-r--r-- | .venv/lib/python3.12/site-packages/rsa/randnum.py | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/.venv/lib/python3.12/site-packages/rsa/randnum.py b/.venv/lib/python3.12/site-packages/rsa/randnum.py new file mode 100644 index 00000000..bb255c57 --- /dev/null +++ b/.venv/lib/python3.12/site-packages/rsa/randnum.py @@ -0,0 +1,95 @@ +# Copyright 2011 Sybren A. Stüvel <sybren@stuvel.eu>
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Functions for generating random numbers."""
+
+# Source inspired by code by Yesudeep Mangalapilly <yesudeep@gmail.com>
+
+import os
+import struct
+
+from rsa import common, transform
+
+
+def read_random_bits(nbits: int) -> bytes:
+ """Reads 'nbits' random bits.
+
+ If nbits isn't a whole number of bytes, an extra byte will be appended with
+ only the lower bits set.
+ """
+
+ nbytes, rbits = divmod(nbits, 8)
+
+ # Get the random bytes
+ randomdata = os.urandom(nbytes)
+
+ # Add the remaining random bits
+ if rbits > 0:
+ randomvalue = ord(os.urandom(1))
+ randomvalue >>= 8 - rbits
+ randomdata = struct.pack("B", randomvalue) + randomdata
+
+ return randomdata
+
+
+def read_random_int(nbits: int) -> int:
+ """Reads a random integer of approximately nbits bits."""
+
+ randomdata = read_random_bits(nbits)
+ value = transform.bytes2int(randomdata)
+
+ # Ensure that the number is large enough to just fill out the required
+ # number of bits.
+ value |= 1 << (nbits - 1)
+
+ return value
+
+
+def read_random_odd_int(nbits: int) -> int:
+ """Reads a random odd integer of approximately nbits bits.
+
+ >>> read_random_odd_int(512) & 1
+ 1
+ """
+
+ value = read_random_int(nbits)
+
+ # Make sure it's odd
+ return value | 1
+
+
+def randint(maxvalue: int) -> int:
+ """Returns a random integer x with 1 <= x <= maxvalue
+
+ May take a very long time in specific situations. If maxvalue needs N bits
+ to store, the closer maxvalue is to (2 ** N) - 1, the faster this function
+ is.
+ """
+
+ bit_size = common.bit_size(maxvalue)
+
+ tries = 0
+ while True:
+ value = read_random_int(bit_size)
+ if value <= maxvalue:
+ break
+
+ if tries % 10 == 0 and tries:
+ # After a lot of tries to get the right number of bits but still
+ # smaller than maxvalue, decrease the number of bits by 1. That'll
+ # dramatically increase the chances to get a large enough number.
+ bit_size -= 1
+ tries += 1
+
+ return value
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