diff --git a/build.json b/build.json
index 2e675d877..e6829710b 100644
--- a/build.json
+++ b/build.json
@@ -301,6 +301,7 @@
             "crypto/refcount.c",
             "crypto/rsa_extra/rsa_asn1.c",
             "crypto/rsa_extra/rsa_crypt.c",
+            "crypto/rsa_extra/rsa_extra.c",
             "crypto/rsa_extra/rsa_print.c",
             "crypto/sha/sha1.c",
             "crypto/sha/sha256.c",
diff --git a/crypto/dsa/internal.h b/crypto/dsa/internal.h
index 9cceeb121..61cf9a65b 100644
--- a/crypto/dsa/internal.h
+++ b/crypto/dsa/internal.h
@@ -42,8 +42,6 @@ struct dsa_st {
   CRYPTO_EX_DATA ex_data;
 };
 
-#define OPENSSL_DSA_MAX_MODULUS_BITS 10000
-
 // dsa_check_key performs cheap self-checks on |dsa|, and ensures it is within
 // DoS bounds. It returns one on success and zero on error.
 int dsa_check_key(const DSA *dsa);
diff --git a/crypto/ec_extra/ec_asn1.c b/crypto/ec_extra/ec_asn1.c
index fb12e48bc..f17cc50af 100644
--- a/crypto/ec_extra/ec_asn1.c
+++ b/crypto/ec_extra/ec_asn1.c
@@ -478,6 +478,41 @@ int i2d_ECPrivateKey(const EC_KEY *key, uint8_t **outp) {
   return CBB_finish_i2d(&cbb, outp);
 }
 
+EC_GROUP *d2i_ECPKParameters(EC_GROUP **out, const uint8_t **inp, long len) {
+  if (len < 0) {
+    return NULL;
+  }
+
+  CBS cbs;
+  CBS_init(&cbs, *inp, (size_t)len);
+  EC_GROUP *ret = EC_KEY_parse_parameters(&cbs);
+  if (ret == NULL) {
+    return NULL;
+  }
+
+  if (out != NULL) {
+    EC_GROUP_free(*out);
+    *out = ret;
+  }
+  *inp = CBS_data(&cbs);
+  return ret;
+}
+
+int i2d_ECPKParameters(const EC_GROUP *group, uint8_t **outp) {
+  if (group == NULL) {
+    OPENSSL_PUT_ERROR(EC, ERR_R_PASSED_NULL_PARAMETER);
+    return -1;
+  }
+
+  CBB cbb;
+  if (!CBB_init(&cbb, 0) ||  //
+      !EC_KEY_marshal_curve_name(&cbb, group)) {
+    CBB_cleanup(&cbb);
+    return -1;
+  }
+  return CBB_finish_i2d(&cbb, outp);
+}
+
 EC_KEY *d2i_ECParameters(EC_KEY **out_key, const uint8_t **inp, long len) {
   if (len < 0) {
     return NULL;
diff --git a/crypto/fipsmodule/dh/internal.h b/crypto/fipsmodule/dh/internal.h
index d11e59b50..9c5830ba5 100644
--- a/crypto/fipsmodule/dh/internal.h
+++ b/crypto/fipsmodule/dh/internal.h
@@ -26,8 +26,6 @@ extern "C" {
 #endif
 
 
-#define OPENSSL_DH_MAX_MODULUS_BITS 10000
-
 struct dh_st {
   BIGNUM *p;
   BIGNUM *g;
diff --git a/crypto/fipsmodule/rsa/rsa_impl.c.inc b/crypto/fipsmodule/rsa/rsa_impl.c.inc
index 2f1d76ba4..c7af4fc99 100644
--- a/crypto/fipsmodule/rsa/rsa_impl.c.inc
+++ b/crypto/fipsmodule/rsa/rsa_impl.c.inc
@@ -79,10 +79,8 @@ int rsa_check_public_key(const RSA *rsa) {
     return 0;
   }
 
-  // TODO(davidben): 16384-bit RSA is huge. Can we bring this down to a limit of
-  // 8192-bit?
   unsigned n_bits = BN_num_bits(rsa->n);
-  if (n_bits > 16 * 1024) {
+  if (n_bits > OPENSSL_RSA_MAX_MODULUS_BITS) {
     OPENSSL_PUT_ERROR(RSA, RSA_R_MODULUS_TOO_LARGE);
     return 0;
   }
diff --git a/crypto/rsa_extra/rsa_extra.c b/crypto/rsa_extra/rsa_extra.c
new file mode 100644
index 000000000..2ed2c10df
--- /dev/null
+++ b/crypto/rsa_extra/rsa_extra.c
@@ -0,0 +1,17 @@
+/* Copyright (c) 2024, Google Inc.
+ *
+ * Permission to use, copy, modify, and/or distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */
+
+#include <openssl/rsa.h>
+
+void RSA_blinding_off(RSA *rsa) {}
diff --git a/gen/sources.bzl b/gen/sources.bzl
index dce527b5f..1eef08959 100644
--- a/gen/sources.bzl
+++ b/gen/sources.bzl
@@ -396,6 +396,7 @@ crypto_sources = [
     "crypto/refcount.c",
     "crypto/rsa_extra/rsa_asn1.c",
     "crypto/rsa_extra/rsa_crypt.c",
+    "crypto/rsa_extra/rsa_extra.c",
     "crypto/rsa_extra/rsa_print.c",
     "crypto/sha/sha1.c",
     "crypto/sha/sha256.c",
diff --git a/gen/sources.cmake b/gen/sources.cmake
index cf8d5f956..933595939 100644
--- a/gen/sources.cmake
+++ b/gen/sources.cmake
@@ -410,6 +410,7 @@ set(
   crypto/refcount.c
   crypto/rsa_extra/rsa_asn1.c
   crypto/rsa_extra/rsa_crypt.c
+  crypto/rsa_extra/rsa_extra.c
   crypto/rsa_extra/rsa_print.c
   crypto/sha/sha1.c
   crypto/sha/sha256.c
diff --git a/gen/sources.gni b/gen/sources.gni
index 41b4cc129..36b50c8a7 100644
--- a/gen/sources.gni
+++ b/gen/sources.gni
@@ -396,6 +396,7 @@ crypto_sources = [
   "crypto/refcount.c",
   "crypto/rsa_extra/rsa_asn1.c",
   "crypto/rsa_extra/rsa_crypt.c",
+  "crypto/rsa_extra/rsa_extra.c",
   "crypto/rsa_extra/rsa_print.c",
   "crypto/sha/sha1.c",
   "crypto/sha/sha256.c",
diff --git a/gen/sources.json b/gen/sources.json
index ec5a7e720..9587ab24b 100644
--- a/gen/sources.json
+++ b/gen/sources.json
@@ -380,6 +380,7 @@
       "crypto/refcount.c",
       "crypto/rsa_extra/rsa_asn1.c",
       "crypto/rsa_extra/rsa_crypt.c",
+      "crypto/rsa_extra/rsa_extra.c",
       "crypto/rsa_extra/rsa_print.c",
       "crypto/sha/sha1.c",
       "crypto/sha/sha256.c",
diff --git a/include/openssl/dh.h b/include/openssl/dh.h
index 6373bbbfa..6e6ddb8c9 100644
--- a/include/openssl/dh.h
+++ b/include/openssl/dh.h
@@ -96,6 +96,10 @@ OPENSSL_EXPORT int DH_up_ref(DH *dh);
 
 // Properties.
 
+// OPENSSL_DH_MAX_MODULUS_BITS is the maximum supported Diffie-Hellman group
+// modulus, in bits.
+#define OPENSSL_DH_MAX_MODULUS_BITS 10000
+
 // DH_bits returns the size of |dh|'s group modulus, in bits.
 OPENSSL_EXPORT unsigned DH_bits(const DH *dh);
 
diff --git a/include/openssl/dsa.h b/include/openssl/dsa.h
index f46a8fcd5..6ebe4aad2 100644
--- a/include/openssl/dsa.h
+++ b/include/openssl/dsa.h
@@ -99,6 +99,10 @@ OPENSSL_EXPORT int DSA_up_ref(DSA *dsa);
 
 // Properties.
 
+// OPENSSL_DSA_MAX_MODULUS_BITS is the maximum supported DSA group modulus, in
+// bits.
+#define OPENSSL_DSA_MAX_MODULUS_BITS 10000
+
 // DSA_bits returns the size of |dsa|'s group modulus, in bits.
 OPENSSL_EXPORT unsigned DSA_bits(const DSA *dsa);
 
diff --git a/include/openssl/ec_key.h b/include/openssl/ec_key.h
index b7bc74cb0..e7c7ef97d 100644
--- a/include/openssl/ec_key.h
+++ b/include/openssl/ec_key.h
@@ -351,8 +351,24 @@ OPENSSL_EXPORT EC_KEY *d2i_ECPrivateKey(EC_KEY **out_key, const uint8_t **inp,
 // Use |EC_KEY_marshal_private_key| instead.
 OPENSSL_EXPORT int i2d_ECPrivateKey(const EC_KEY *key, uint8_t **outp);
 
+// d2i_ECPKParameters parses a DER-encoded ECParameters structure (RFC 5480)
+// from |len| bytes at |*inp|, as described in |d2i_SAMPLE|. For legacy reasons,
+// it recognizes the specifiedCurve form, but only for curves that are already
+// supported as named curves.
+//
+// Use |EC_KEY_parse_parameters| or |EC_KEY_parse_curve_name| instead.
+OPENSSL_EXPORT EC_GROUP *d2i_ECPKParameters(EC_GROUP **out, const uint8_t **inp,
+                                            long len);
+
+// i2d_ECPKParameters marshals |group| as a DER-encoded ECParameters structure
+// (RFC 5480), as described in |i2d_SAMPLE|.
+//
+// Use |EC_KEY_marshal_curve_name| instead.
+OPENSSL_EXPORT int i2d_ECPKParameters(const EC_GROUP *group, uint8_t **outp);
+
 // d2i_ECParameters parses a DER-encoded ECParameters structure (RFC 5480) from
-// |len| bytes at |*inp|, as described in |d2i_SAMPLE|.
+// |len| bytes at |*inp|, as described in |d2i_SAMPLE|. It returns the result as
+// an |EC_KEY| with parameters, but no key, configured.
 //
 // Use |EC_KEY_parse_parameters| or |EC_KEY_parse_curve_name| instead.
 OPENSSL_EXPORT EC_KEY *d2i_ECParameters(EC_KEY **out_key, const uint8_t **inp,
diff --git a/include/openssl/rsa.h b/include/openssl/rsa.h
index 5bf2b50dc..545b73bfe 100644
--- a/include/openssl/rsa.h
+++ b/include/openssl/rsa.h
@@ -111,6 +111,11 @@ OPENSSL_EXPORT int RSA_up_ref(RSA *rsa);
 
 // Properties.
 
+// OPENSSL_RSA_MAX_MODULUS_BITS is the maximum supported RSA modulus, in bits.
+//
+// TODO(davidben): Reduce this to 8192.
+#define OPENSSL_RSA_MAX_MODULUS_BITS 16384
+
 // RSA_bits returns the size of |rsa|, in bits.
 OPENSSL_EXPORT unsigned RSA_bits(const RSA *rsa);
 
@@ -670,11 +675,8 @@ OPENSSL_EXPORT void *RSA_get_ex_data(const RSA *rsa, int idx);
 #define RSA_FLAG_OPAQUE 1
 
 // RSA_FLAG_NO_BLINDING disables blinding of private operations, which is a
-// dangerous thing to do. It is deprecated and should not be used. It will
-// be ignored whenever possible.
-//
-// This flag must be used if a key without the public exponent |e| is used for
-// private key operations; avoid using such keys whenever possible.
+// dangerous thing to do. This flag is set internally as part of self-tests but
+// is otherwise impossible to set externally.
 #define RSA_FLAG_NO_BLINDING 8
 
 // RSA_FLAG_EXT_PKEY is deprecated and ignored.
@@ -712,6 +714,9 @@ OPENSSL_EXPORT int RSA_test_flags(const RSA *rsa, int flags);
 // RSA_blinding_on returns one.
 OPENSSL_EXPORT int RSA_blinding_on(RSA *rsa, BN_CTX *ctx);
 
+// RSA_blinding_off does nothing.
+OPENSSL_EXPORT void RSA_blinding_off(RSA *rsa);
+
 // RSA_generate_key behaves like |RSA_generate_key_ex|, which is what you
 // should use instead. It returns NULL on error, or a newly-allocated |RSA| on
 // success. This function is provided for compatibility only. The |callback|