Don't generate RSA keys <1024 bits (#10278)

* Don't generate RSA keys <1024 bits

* Update CHANGELOG.rst

Author: alex

CHANGELOG.rst

@@ -8,6 +8,11 @@ Changelog
 
 .. note:: This version is not yet released and is under active development.
 
+* :func:`~cryptography.hazmat.primitives.asymmetric.rsa.generate_private_key`
+  now enforces a minimum RSA key size of 1024-bit. Note that 1024-bit is still
+  considered insecure, users should generally use a key size of 2048-bits.
+
+
 .. _v42-0-1:
 
 42.0.1 - 2024-01-24

src/cryptography/hazmat/primitives/asymmetric/rsa.py

@@ -150,8 +150,8 @@ def _verify_rsa_parameters(public_exponent: int, key_size: int) -> None:
             "65537. Almost everyone should choose 65537 here!"
         )
 
-    if key_size < 512:
-        raise ValueError("key_size must be at least 512-bits.")
+    if key_size < 1024:
+        raise ValueError("key_size must be at least 1024-bits.")
 
 
 def _modinv(e: int, m: int) -> int: