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Merged
alex merged 4 commits into from
Feb 28, 2026
Merged

remove binary curve support #14291

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f52c528
remove binary curve support
reaperhulk Feb 10, 2026
32ae467
more sect
reaperhulk Feb 10, 2026
68b7b79
better assert
reaperhulk Feb 10, 2026
5c1dfbf
unwrap :feelsbadman:
reaperhulk Feb 28, 2026
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3 changes: 3 additions & 0 deletions CHANGELOG.rst
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Expand Up @@ -10,6 +10,9 @@ Changelog

* Support for Python 3.8 is deprecated and will be removed in the next
``cryptography`` release.
* **BACKWARDS INCOMPATIBLE:** Support for binary elliptic curves
(``SECT*`` classes) has been removed. These curves are rarely used and
have additional security considerations that make them undesirable.
* **BACKWARDS INCOMPATIBLE:** Support for OpenSSL 1.1.x has been removed.
OpenSSL 3.0.0 or later is now required. LibreSSL, BoringSSL, and AWS-LC
continue to be supported.
Expand Down
141 changes: 0 additions & 141 deletions docs/hazmat/primitives/asymmetric/ec.rst
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Expand Up @@ -395,87 +395,6 @@ All named curves are instances of :class:`EllipticCurve`.
Brainpool curve specified in :rfc:`5639`. These curves are discouraged
for new systems.

.. class:: SECT571K1

.. versionadded:: 0.5

SECG curve ``sect571k1``. Also called NIST K-571. These binary curves are
discouraged for new systems.


.. class:: SECT409K1

.. versionadded:: 0.5

SECG curve ``sect409k1``. Also called NIST K-409. These binary curves are
discouraged for new systems.


.. class:: SECT283K1

.. versionadded:: 0.5

SECG curve ``sect283k1``. Also called NIST K-283. These binary curves are
discouraged for new systems.


.. class:: SECT233K1

.. versionadded:: 0.5

SECG curve ``sect233k1``. Also called NIST K-233. These binary curves are
discouraged for new systems.


.. class:: SECT163K1

.. versionadded:: 0.5

SECG curve ``sect163k1``. Also called NIST K-163. These binary curves are
discouraged for new systems.


.. class:: SECT571R1

.. versionadded:: 0.5

SECG curve ``sect571r1``. Also called NIST B-571. These binary curves are
discouraged for new systems.


.. class:: SECT409R1

.. versionadded:: 0.5

SECG curve ``sect409r1``. Also called NIST B-409. These binary curves are
discouraged for new systems.


.. class:: SECT283R1

.. versionadded:: 0.5

SECG curve ``sect283r1``. Also called NIST B-283. These binary curves are
discouraged for new systems.


.. class:: SECT233R1

.. versionadded:: 0.5

SECG curve ``sect233r1``. Also called NIST B-233. These binary curves are
discouraged for new systems.


.. class:: SECT163R2

.. versionadded:: 0.5

SECG curve ``sect163r2``. Also called NIST B-163. These binary curves are
discouraged for new systems.




Key Interfaces
~~~~~~~~~~~~~~
Expand Down Expand Up @@ -832,66 +751,6 @@ Elliptic Curve Object Identifiers

Corresponds to the dotted string ``"1.3.36.3.3.2.8.1.1.13"``.

.. attribute:: SECT163K1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.1"``.

.. attribute:: SECT163R2

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.15"``.

.. attribute:: SECT233K1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.26"``.

.. attribute:: SECT233R1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.27"``.

.. attribute:: SECT283K1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.16"``.

.. attribute:: SECT283R1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.17"``.

.. attribute:: SECT409K1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.36"``.

.. attribute:: SECT409R1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.37"``.

.. attribute:: SECT571K1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.38"``.

.. attribute:: SECT571R1

.. versionadded:: 2.5

Corresponds to the dotted string ``"1.3.132.0.39"``.

.. function:: get_curve_for_oid(oid)

.. versionadded:: 2.6
Expand Down
90 changes: 0 additions & 90 deletions src/cryptography/hazmat/primitives/asymmetric/ec.py
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Expand Up @@ -25,16 +25,6 @@ class EllipticCurveOID:
BRAINPOOLP256R1 = ObjectIdentifier("1.3.36.3.3.2.8.1.1.7")
BRAINPOOLP384R1 = ObjectIdentifier("1.3.36.3.3.2.8.1.1.11")
BRAINPOOLP512R1 = ObjectIdentifier("1.3.36.3.3.2.8.1.1.13")
SECT163K1 = ObjectIdentifier("1.3.132.0.1")
SECT163R2 = ObjectIdentifier("1.3.132.0.15")
SECT233K1 = ObjectIdentifier("1.3.132.0.26")
SECT233R1 = ObjectIdentifier("1.3.132.0.27")
SECT283K1 = ObjectIdentifier("1.3.132.0.16")
SECT283R1 = ObjectIdentifier("1.3.132.0.17")
SECT409K1 = ObjectIdentifier("1.3.132.0.36")
SECT409R1 = ObjectIdentifier("1.3.132.0.37")
SECT571K1 = ObjectIdentifier("1.3.132.0.38")
SECT571R1 = ObjectIdentifier("1.3.132.0.39")


class EllipticCurve(metaclass=abc.ABCMeta):
Expand Down Expand Up @@ -227,66 +217,6 @@ def __deepcopy__(self, memo: dict) -> EllipticCurvePublicKey:
EllipticCurvePublicNumbers = rust_openssl.ec.EllipticCurvePublicNumbers


class SECT571R1(EllipticCurve):
name = "sect571r1"
key_size = 570
group_order = 0x3FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE661CE18FF55987308059B186823851EC7DD9CA1161DE93D5174D66E8382E9BB2FE84E47 # noqa: E501


class SECT409R1(EllipticCurve):
name = "sect409r1"
key_size = 409
group_order = 0x10000000000000000000000000000000000000000000000000001E2AAD6A612F33307BE5FA47C3C9E052F838164CD37D9A21173 # noqa: E501


class SECT283R1(EllipticCurve):
name = "sect283r1"
key_size = 282
group_order = 0x3FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFEF90399660FC938A90165B042A7CEFADB307 # noqa: E501


class SECT233R1(EllipticCurve):
name = "sect233r1"
key_size = 233
group_order = 0x1000000000000000000000000000013E974E72F8A6922031D2603CFE0D7


class SECT163R2(EllipticCurve):
name = "sect163r2"
key_size = 163
group_order = 0x40000000000000000000292FE77E70C12A4234C33


class SECT571K1(EllipticCurve):
name = "sect571k1"
key_size = 570
group_order = 0x20000000000000000000000000000000000000000000000000000000000000000000000131850E1F19A63E4B391A8DB917F4138B630D84BE5D639381E91DEB45CFE778F637C1001 # noqa: E501


class SECT409K1(EllipticCurve):
name = "sect409k1"
key_size = 407
group_order = 0x7FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE5F83B2D4EA20400EC4557D5ED3E3E7CA5B4B5C83B8E01E5FCF # noqa: E501


class SECT283K1(EllipticCurve):
name = "sect283k1"
key_size = 281
group_order = 0x1FFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFFE9AE2ED07577265DFF7F94451E061E163C61 # noqa: E501


class SECT233K1(EllipticCurve):
name = "sect233k1"
key_size = 232
group_order = 0x8000000000000000000000000000069D5BB915BCD46EFB1AD5F173ABDF


class SECT163K1(EllipticCurve):
name = "sect163k1"
key_size = 163
group_order = 0x4000000000000000000020108A2E0CC0D99F8A5EF


class SECP521R1(EllipticCurve):
name = "secp521r1"
key_size = 521
Expand Down Expand Up @@ -356,16 +286,6 @@ class BrainpoolP512R1(EllipticCurve):
"secp384r1": SECP384R1(),
"secp521r1": SECP521R1(),
"secp256k1": SECP256K1(),
"sect163k1": SECT163K1(),
"sect233k1": SECT233K1(),
"sect283k1": SECT283K1(),
"sect409k1": SECT409K1(),
"sect571k1": SECT571K1(),
"sect163r2": SECT163R2(),
"sect233r1": SECT233R1(),
"sect283r1": SECT283R1(),
"sect409r1": SECT409R1(),
"sect571r1": SECT571R1(),
"brainpoolP256r1": BrainpoolP256R1(),
"brainpoolP384r1": BrainpoolP384R1(),
"brainpoolP512r1": BrainpoolP512R1(),
Expand Down Expand Up @@ -436,16 +356,6 @@ class ECDH:
EllipticCurveOID.BRAINPOOLP256R1: BrainpoolP256R1,
EllipticCurveOID.BRAINPOOLP384R1: BrainpoolP384R1,
EllipticCurveOID.BRAINPOOLP512R1: BrainpoolP512R1,
EllipticCurveOID.SECT163K1: SECT163K1,
EllipticCurveOID.SECT163R2: SECT163R2,
EllipticCurveOID.SECT233K1: SECT233K1,
EllipticCurveOID.SECT233R1: SECT233R1,
EllipticCurveOID.SECT283K1: SECT283K1,
EllipticCurveOID.SECT283R1: SECT283R1,
EllipticCurveOID.SECT409K1: SECT409K1,
EllipticCurveOID.SECT409R1: SECT409R1,
EllipticCurveOID.SECT571K1: SECT571K1,
EllipticCurveOID.SECT571R1: SECT571R1,
}


Expand Down
23 changes: 0 additions & 23 deletions src/rust/cryptography-key-parsing/src/ec.rs
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Expand Up @@ -29,16 +29,6 @@ pub(crate) fn group_to_curve_oid(
openssl::nid::Nid::SECP384R1 => Some(cryptography_x509::oid::EC_SECP384R1),
openssl::nid::Nid::SECP521R1 => Some(cryptography_x509::oid::EC_SECP521R1),
openssl::nid::Nid::SECP256K1 => Some(cryptography_x509::oid::EC_SECP256K1),
openssl::nid::Nid::SECT233R1 => Some(cryptography_x509::oid::EC_SECT233R1),
openssl::nid::Nid::SECT283R1 => Some(cryptography_x509::oid::EC_SECT283R1),
openssl::nid::Nid::SECT409R1 => Some(cryptography_x509::oid::EC_SECT409R1),
openssl::nid::Nid::SECT571R1 => Some(cryptography_x509::oid::EC_SECT571R1),
openssl::nid::Nid::SECT163R2 => Some(cryptography_x509::oid::EC_SECT163R2),
openssl::nid::Nid::SECT163K1 => Some(cryptography_x509::oid::EC_SECT163K1),
openssl::nid::Nid::SECT233K1 => Some(cryptography_x509::oid::EC_SECT233K1),
openssl::nid::Nid::SECT283K1 => Some(cryptography_x509::oid::EC_SECT283K1),
openssl::nid::Nid::SECT409K1 => Some(cryptography_x509::oid::EC_SECT409K1),
openssl::nid::Nid::SECT571K1 => Some(cryptography_x509::oid::EC_SECT571K1),
#[cfg(not(any(CRYPTOGRAPHY_IS_BORINGSSL, CRYPTOGRAPHY_IS_AWSLC)))]
openssl::nid::Nid::BRAINPOOL_P256R1 => Some(cryptography_x509::oid::EC_BRAINPOOLP256R1),
#[cfg(not(any(CRYPTOGRAPHY_IS_BORINGSSL, CRYPTOGRAPHY_IS_AWSLC)))]
Expand All @@ -63,19 +53,6 @@ pub(crate) fn ec_params_to_group(

&cryptography_x509::oid::EC_SECP256K1 => openssl::nid::Nid::SECP256K1,

&cryptography_x509::oid::EC_SECT233R1 => openssl::nid::Nid::SECT233R1,
&cryptography_x509::oid::EC_SECT283R1 => openssl::nid::Nid::SECT283R1,
&cryptography_x509::oid::EC_SECT409R1 => openssl::nid::Nid::SECT409R1,
&cryptography_x509::oid::EC_SECT571R1 => openssl::nid::Nid::SECT571R1,

&cryptography_x509::oid::EC_SECT163R2 => openssl::nid::Nid::SECT163R2,

&cryptography_x509::oid::EC_SECT163K1 => openssl::nid::Nid::SECT163K1,
&cryptography_x509::oid::EC_SECT233K1 => openssl::nid::Nid::SECT233K1,
&cryptography_x509::oid::EC_SECT283K1 => openssl::nid::Nid::SECT283K1,
&cryptography_x509::oid::EC_SECT409K1 => openssl::nid::Nid::SECT409K1,
&cryptography_x509::oid::EC_SECT571K1 => openssl::nid::Nid::SECT571K1,

#[cfg(not(any(CRYPTOGRAPHY_IS_BORINGSSL, CRYPTOGRAPHY_IS_AWSLC)))]
&cryptography_x509::oid::EC_BRAINPOOLP256R1 => openssl::nid::Nid::BRAINPOOL_P256R1,
#[cfg(not(any(CRYPTOGRAPHY_IS_BORINGSSL, CRYPTOGRAPHY_IS_AWSLC)))]
Expand Down
13 changes: 0 additions & 13 deletions src/rust/cryptography-x509/src/oid.rs
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Expand Up @@ -58,19 +58,6 @@ pub const EC_SECP521R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 35);

pub const EC_SECP256K1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 10);

pub const EC_SECT233R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 27);
pub const EC_SECT283R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 17);
pub const EC_SECT409R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 37);
pub const EC_SECT571R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 39);

pub const EC_SECT163R2: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 15);

pub const EC_SECT163K1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 1);
pub const EC_SECT233K1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 26);
pub const EC_SECT283K1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 16);
pub const EC_SECT409K1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 36);
pub const EC_SECT571K1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 132, 0, 38);

pub const EC_BRAINPOOLP256R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 36, 3, 3, 2, 8, 1, 1, 7);
pub const EC_BRAINPOOLP384R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 36, 3, 3, 2, 8, 1, 1, 11);
pub const EC_BRAINPOOLP512R1: asn1::ObjectIdentifier = asn1::oid!(1, 3, 36, 3, 3, 2, 8, 1, 1, 13);
Expand Down
29 changes: 12 additions & 17 deletions src/rust/src/backend/ec.rs
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Expand Up @@ -47,19 +47,6 @@ fn curve_from_py_curve(

"secp256k1" => openssl::nid::Nid::SECP256K1,

"sect233r1" => openssl::nid::Nid::SECT233R1,
"sect283r1" => openssl::nid::Nid::SECT283R1,
"sect409r1" => openssl::nid::Nid::SECT409R1,
"sect571r1" => openssl::nid::Nid::SECT571R1,

"sect163r2" => openssl::nid::Nid::SECT163R2,

"sect163k1" => openssl::nid::Nid::SECT163K1,
"sect233k1" => openssl::nid::Nid::SECT233K1,
"sect283k1" => openssl::nid::Nid::SECT283K1,
"sect409k1" => openssl::nid::Nid::SECT409K1,
"sect571k1" => openssl::nid::Nid::SECT571K1,

#[cfg(not(any(CRYPTOGRAPHY_IS_BORINGSSL, CRYPTOGRAPHY_IS_AWSLC)))]
"brainpoolP256r1" => openssl::nid::Nid::BRAINPOOL_P256R1,
#[cfg(not(any(CRYPTOGRAPHY_IS_BORINGSSL, CRYPTOGRAPHY_IS_AWSLC)))]
Expand Down Expand Up @@ -249,9 +236,11 @@ impl ECPrivateKey {

let len = deriver.len()?;
Ok(pyo3::types::PyBytes::new_with(py, len, |b| {
let n = py.detach(|| deriver.derive(b)).map_err(|_| {
pyo3::exceptions::PyValueError::new_err("Error computing shared key.")
})?;
// Previously it was possible to have derive return an error
// if a public key was in a subgroup. Now that we only
// support cofactor 1 curves this should be unreachable
// so we unwrap.
let n = py.detach(|| deriver.derive(b)).unwrap();
assert_eq!(n, b.len());
Ok(())
})?)
Expand Down Expand Up @@ -389,7 +378,13 @@ impl ECPublicKey {
) -> CryptographyResult<ECPublicKey> {
let ec = pkey.ec_key()?;
check_key_infinity(&ec)?;

let mut bn_ctx = openssl::bn::BigNumContext::new()?;
let mut cofactor = openssl::bn::BigNum::new()?;
ec.group().cofactor(&mut cofactor, &mut bn_ctx)?;
let one = openssl::bn::BigNum::from_u32(1)?;
// We only support curves with a cofactor of 1.
// Any change here requires more careful key checking
assert_eq!(cofactor, one, "cofactor must be 1");
Ok(ECPublicKey { pkey, curve })
}
}
Expand Down
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