script/dom/webcrypto/subtlecrypto/

ec_common.rs

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at https://mozilla.org/MPL/2.0/. */

use elliptic_curve::pkcs8::{DecodePrivateKey, DecodePublicKey, EncodePrivateKey, EncodePublicKey};
use elliptic_curve::sec1::{ModulusSize, Sec1Point, ToSec1Point, ValidatePublicKey};
use elliptic_curve::{Curve, FieldBytesSize, Generate, PublicKey, SecretKey};
use js::context::JSContext;
use p256::NistP256;
use p384::NistP384;
use p521::NistP521;

use crate::dom::bindings::codegen::Bindings::CryptoKeyBinding::{
    CryptoKeyMethods, CryptoKeyPair, KeyType, KeyUsage,
};
use crate::dom::bindings::codegen::Bindings::SubtleCryptoBinding::{JsonWebKey, KeyFormat};
use crate::dom::bindings::error::{Error, ErrorResult};
use crate::dom::bindings::root::DomRoot;
use crate::dom::bindings::str::DOMString;
use crate::dom::cryptokey::{CryptoKey, Handle};
use crate::dom::globalscope::GlobalScope;
use crate::dom::subtlecrypto::{
    CryptoAlgorithm, ExportedKey, JwkStringField, KeyAlgorithmAndDerivatives, NAMED_CURVE_P256,
    NAMED_CURVE_P384, NAMED_CURVE_P521, SUPPORTED_CURVES, SubtleEcKeyAlgorithm,
    SubtleEcKeyGenParams, SubtleEcKeyImportParams,
};
use crate::dom::webcrypto::subtlecrypto::JsonWebKeyExt;

#[derive(PartialEq)]
pub(crate) enum EcAlgorithm {
    Ecdsa,
    Ecdh,
}

/// <https://w3c.github.io/webcrypto/#ecdsa-operations-generate-key>
/// <https://w3c.github.io/webcrypto/#ecdh-operations-generate-key>
pub(crate) fn generate_key(
    ec_algorithm: EcAlgorithm,
    cx: &mut JSContext,
    global: &GlobalScope,
    normalized_algorithm: &SubtleEcKeyGenParams,
    extractable: bool,
    usages: Vec<KeyUsage>,
) -> Result<CryptoKeyPair, Error> {
    match ec_algorithm {
        EcAlgorithm::Ecdsa => {
            // Step 1. If usages contains a value which is not one of "sign" or "verify", then throw
            // a SyntaxError.
            if usages
                .iter()
                .any(|usage| !matches!(usage, KeyUsage::Sign | KeyUsage::Verify))
            {
                return Err(Error::Syntax(Some(
                    "Usages contains an entry which is not \"sign\" or \"verify\"".into(),
                )));
            }
        },
        EcAlgorithm::Ecdh => {
            // Step 1. If usages contains an entry which is not "deriveKey" or "deriveBits" then
            // throw a SyntaxError.
            if usages
                .iter()
                .any(|usage| !matches!(usage, KeyUsage::DeriveKey | KeyUsage::DeriveBits))
            {
                return Err(Error::Syntax(Some(
                    "Usages contains an entry which is not \"deriveKey\" or \"deriveBits\"".into(),
                )));
            }
        },
    }

    // Step 2.
    // If the namedCurve member of normalizedAlgorithm is "P-256", "P-384" or "P-521":
    //     Generate an Elliptic Curve key pair, as defined in [RFC6090] with domain parameters for
    //     the curve identified by the namedCurve member of normalizedAlgorithm.
    // If the namedCurve member of normalizedAlgorithm is a value specified in an applicable
    // specification:
    //     Perform the ECDSA generation steps specified in that specification, passing in
    //     normalizedAlgorithm and resulting in an elliptic curve key pair.
    // Otherwise:
    //     throw a NotSupportedError
    // Step 3. If performing the key generation operation results in an error, then throw an
    // OperationError.
    // NOTE: We currently do not support other applicable specifications.
    let (private_key_handle, public_key_handle) = match normalized_algorithm.named_curve.as_str() {
        NAMED_CURVE_P256 => {
            let private_key = SecretKey::<NistP256>::try_generate().map_err(|_| {
                Error::Operation(Some("Failed to generate P-256 private key".into()))
            })?;
            let public_key = private_key.public_key();
            (
                Handle::P256PrivateKey(private_key),
                Handle::P256PublicKey(public_key),
            )
        },
        NAMED_CURVE_P384 => {
            let private_key = SecretKey::<NistP384>::try_generate().map_err(|_| {
                Error::Operation(Some("Failed to generate P-384 private key".into()))
            })?;
            let public_key = private_key.public_key();
            (
                Handle::P384PrivateKey(private_key),
                Handle::P384PublicKey(public_key),
            )
        },
        NAMED_CURVE_P521 => {
            let private_key = SecretKey::<NistP521>::try_generate().map_err(|_| {
                Error::Operation(Some("Failed to generate P-521 private key".into()))
            })?;
            let public_key = private_key.public_key();
            (
                Handle::P521PrivateKey(private_key),
                Handle::P521PublicKey(public_key),
            )
        },
        named_curve => {
            return Err(Error::NotSupported(Some(format!(
                "Unsupported named curve: {}",
                named_curve
            ))));
        },
    };

    // Step 4. Let algorithm be a new EcKeyAlgorithm object.
    // Step 6. Set the namedCurve attribute of algorithm to equal the namedCurve member of
    // normalizedAlgorithm.
    let algorithm = SubtleEcKeyAlgorithm {
        name: match ec_algorithm {
            EcAlgorithm::Ecdsa => {
                // Step 5. Set the name attribute of algorithm to "ECDSA".
                CryptoAlgorithm::Ecdsa
            },
            EcAlgorithm::Ecdh => {
                // Step 5. Set the name member of algorithm to "ECDH".
                CryptoAlgorithm::Ecdh
            },
        },
        named_curve: normalized_algorithm.named_curve.clone(),
    };

    // Step 7. Let publicKey be a new CryptoKey representing the public key of the generated key pair.
    // Step 8. Set the [[type]] internal slot of publicKey to "public"
    // Step 9. Set the [[algorithm]] internal slot of publicKey to algorithm.
    // Step 10. Set the [[extractable]] internal slot of publicKey to true.
    let public_key_usage = match ec_algorithm {
        EcAlgorithm::Ecdsa => {
            // Step 11. Set the [[usages]] internal slot of publicKey to be the usage intersection
            // of usages and [ "verify" ].
            usages
                .iter()
                .filter(|usage| **usage == KeyUsage::Verify)
                .cloned()
                .collect()
        },
        EcAlgorithm::Ecdh => {
            // Step 11. Set the [[usages]] internal slot of publicKey to be the empty list.
            Vec::new()
        },
    };
    let public_key = CryptoKey::new(
        cx,
        global,
        KeyType::Public,
        true,
        KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm.clone()),
        public_key_usage,
        public_key_handle,
    );

    // Step 12. Let privateKey be a new CryptoKey representing the private key of the generated key pair.
    // Step 13. Set the [[type]] internal slot of privateKey to "private"
    // Step 14. Set the [[algorithm]] internal slot of privateKey to algorithm.
    // Step 15. Set the [[extractable]] internal slot of privateKey to extractable.
    let private_key_usage = match ec_algorithm {
        EcAlgorithm::Ecdsa => {
            // Step 16. Set the [[usages]] internal slot of privateKey to be the usage intersection
            // of usages and [ "sign" ].
            usages
                .iter()
                .filter(|usage| **usage == KeyUsage::Sign)
                .cloned()
                .collect()
        },
        EcAlgorithm::Ecdh => {
            // Step 16. Set the [[usages]] internal slot of privateKey to be the usage intersection
            // of usages and [ "deriveKey", "deriveBits" ].
            usages
                .iter()
                .filter(|usage| matches!(usage, KeyUsage::DeriveKey | KeyUsage::DeriveBits))
                .cloned()
                .collect()
        },
    };
    let private_key = CryptoKey::new(
        cx,
        global,
        KeyType::Private,
        extractable,
        KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm),
        private_key_usage,
        private_key_handle,
    );

    // Step 17. Let result be a new CryptoKeyPair dictionary.
    // Step 18. Set the publicKey attribute of result to be publicKey.
    // Step 19. Set the privateKey attribute of result to be privateKey.
    let result = CryptoKeyPair {
        publicKey: Some(public_key),
        privateKey: Some(private_key),
    };

    // Step 20. Return result.
    Ok(result)
}

/// <https://w3c.github.io/webcrypto/#ecdsa-operations-import-key>
/// <https://w3c.github.io/webcrypto/#ecdh-operations-import-key>
///
/// This implementation is based on the specification of the importKey operation of ECDSA. When
/// format is "jwk", Step 2.2 and Step 2.3 in the specification of the importKey operation of ECDH
/// are combined into a single step, and Step 2.9.1 to Step 2.9.3. here are skipped for ECDH.
#[allow(clippy::too_many_arguments)]
pub(crate) fn import_key(
    ec_algorithm: EcAlgorithm,
    cx: &mut JSContext,
    global: &GlobalScope,
    normalized_algorithm: &SubtleEcKeyImportParams,
    format: KeyFormat,
    key_data: &[u8],
    extractable: bool,
    usages: Vec<KeyUsage>,
) -> Result<DomRoot<CryptoKey>, Error> {
    // Step 1. Let keyData be the key data to be imported.

    // Step 2.
    let key = match format {
        KeyFormat::Spki => {
            match ec_algorithm {
                EcAlgorithm::Ecdsa => {
                    // Step 2.1. If usages contains a value which is not "verify" then throw a
                    // SyntaxError.
                    if usages.iter().any(|usage| *usage != KeyUsage::Verify) {
                        return Err(Error::Syntax(Some(
                            "Usages contains a value which is not \"verify\"".into(),
                        )));
                    }
                },
                EcAlgorithm::Ecdh => {
                    // Step 2.1. If usages is not empty then throw a SyntaxError.
                    if !usages.is_empty() {
                        return Err(Error::Syntax(Some("Usages list is not empty".into())));
                    }
                },
            }

            // Step 2.2. Let spki be the result of running the parse a subjectPublicKeyInfo
            // algorithm over keyData
            // Step 2.3. If an error occurred while parsing, then throw a DataError.
            // Step 2.4. If the algorithm object identifier field of the algorithm
            // AlgorithmIdentifier field of spki is not equal to the id-ecPublicKey object
            // identifier defined in [RFC5480], then throw a DataError.
            // Step 2.5. If the parameters field of the algorithm AlgorithmIdentifier field of spki
            // is absent, then throw a DataError.
            // Step 2.6. Let params be the parameters field of the algorithm AlgorithmIdentifier
            // field of spki.
            // Step 2.7. If params is not an instance of the ECParameters ASN.1 type defined in
            // [RFC5480] that specifies a namedCurve, then throw a DataError.
            // Step 2.8. Let namedCurve be a string whose initial value is undefined.
            // Step 2.9.
            //     If params is equivalent to the secp256r1 object identifier defined in [RFC5480]:
            //         Set namedCurve "P-256".
            //     If params is equivalent to the secp384r1 object identifier defined in [RFC5480]:
            //         Set namedCurve "P-384".
            //     If params is equivalent to the secp521r1 object identifier defined in [RFC5480]:
            //         Set namedCurve "P-521".
            // Step 2.10.
            //     If namedCurve is not undefined:
            //         Step 2.10.1. Let publicKey be the Elliptic Curve public key identified by
            //         performing the conversion steps defined in Section 2.3.4 of [SEC1] using the
            //         subjectPublicKey field of spki.
            //         Step 2.10.2. The uncompressed point format MUST be supported.
            //         Step 2.10.3. If the implementation does not support the compressed point
            //         format and a compressed point is provided, throw a DataError.
            //         Step 2.10.4. If a decode error occurs or an identity point is found, throw a
            //         DataError.
            //         Step 2.10.5. Let key be a new CryptoKey that represents publicKey.
            //     Otherwise:
            //         Step 2.10.1. Perform any key import steps defined by other applicable
            //         specifications, passing format, spki and obtaining namedCurve and key.
            //         Step 2.10.2. If an error occurred or there are no applicable specifications,
            //         throw a DataError.
            // Step 2.11. If namedCurve is defined, and not equal to the namedCurve member of
            // normalizedAlgorithm, throw a DataError.
            // Step 2.12. If the public key value is not a valid point on the Elliptic Curve
            // identified by the namedCurve member of normalizedAlgorithm throw a DataError.
            let handle = match normalized_algorithm.named_curve.as_str() {
                NAMED_CURVE_P256 => Handle::P256PublicKey(
                    PublicKey::<NistP256>::from_public_key_der(key_data).map_err(|_| {
                        Error::Data(Some(
                            "Failed to parse the P-256 elliptic-curve public key in SPKI format"
                                .into(),
                        ))
                    })?,
                ),
                NAMED_CURVE_P384 => Handle::P384PublicKey(
                    PublicKey::<NistP384>::from_public_key_der(key_data).map_err(|_| {
                        Error::Data(Some(
                            "Failed to parse the P-384 elliptic-curve public key in SPKI format"
                                .into(),
                        ))
                    })?,
                ),
                NAMED_CURVE_P521 => Handle::P521PublicKey(
                    PublicKey::<NistP521>::from_public_key_der(key_data).map_err(|_| {
                        Error::Data(Some(
                            "Failed to parse the P-521 elliptic-curve public key in SPKI format"
                                .into(),
                        ))
                    })?,
                ),
                _ => return Err(Error::Data(Some("Unsupported namedCurve".into()))),
            };

            // Step 2.13. Set the [[type]] internal slot of key to "public"
            // Step 2.14. Let algorithm be a new EcKeyAlgorithm.
            // Step 2.16. Set the namedCurve attribute of algorithm to namedCurve.
            // Step 2.17. Set the [[algorithm]] internal slot of key to algorithm.
            let algorithm = SubtleEcKeyAlgorithm {
                name: match ec_algorithm {
                    EcAlgorithm::Ecdsa => {
                        // Step 2.15. Set the name attribute of algorithm to "ECDSA".
                        CryptoAlgorithm::Ecdsa
                    },
                    EcAlgorithm::Ecdh => {
                        // Step 2.15. Set the name attribute of algorithm to "ECDH".
                        CryptoAlgorithm::Ecdh
                    },
                },
                named_curve: normalized_algorithm.named_curve.clone(),
            };
            CryptoKey::new(
                cx,
                global,
                KeyType::Public,
                extractable,
                KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm),
                usages,
                handle,
            )
        },
        KeyFormat::Pkcs8 => {
            match ec_algorithm {
                EcAlgorithm::Ecdsa => {
                    // Step 2.1. If usages contains a value which is not "sign" then throw a
                    // SyntaxError.
                    if usages.iter().any(|usage| *usage != KeyUsage::Sign) {
                        return Err(Error::Syntax(Some(
                            "Usages contains an entry which is not \"sign\"".into(),
                        )));
                    }
                },
                EcAlgorithm::Ecdh => {
                    // Step 2.1. If usages contains an entry which is not "deriveKey" or
                    // "deriveBits" then throw a SyntaxError.
                    if usages
                        .iter()
                        .any(|usage| !matches!(usage, KeyUsage::DeriveKey | KeyUsage::DeriveBits))
                    {
                        return Err(Error::Syntax(Some(
                            "Usages contains an entry which is not \"deriveKey\" or \"deriveBits\""
                                .into(),
                        )));
                    }
                },
            }

            // Step 2.2. Let privateKeyInfo be the result of running the parse a privateKeyInfo
            // algorithm over keyData.
            // Step 2.3. If an error occurs while parsing, throw a DataError.
            // Step 2.4. If the algorithm object identifier field of the privateKeyAlgorithm
            // PrivateKeyAlgorithm field of privateKeyInfo is not equal to the id-ecPublicKey
            // object identifier defined in [RFC5480], throw a DataError.
            // Step 2.5. If the parameters field of the privateKeyAlgorithm
            // PrivateKeyAlgorithmIdentifier field of privateKeyInfo is not present, throw a
            // DataError.
            // Step 2.6. Let params be the parameters field of the privateKeyAlgorithm
            // PrivateKeyAlgorithmIdentifier field of privateKeyInfo.
            // Step 2.7. If params is not an instance of the ECParameters ASN.1 type defined in
            // [RFC5480] that specifies a namedCurve, then throw a DataError.
            // Step 2.8. Let namedCurve be a string whose initial value is undefined.
            // Step 2.9.
            //     If params is equivalent to the secp256r1 object identifier defined in [RFC5480]:
            //         Set namedCurve to "P-256".
            //     If params is equivalent to the secp384r1 object identifier defined in [RFC5480]:
            //         Set namedCurve to "P-384".
            //     If params is equivalent to the secp521r1 object identifier defined in [RFC5480]:
            //         Set namedCurve to "P-521".
            // Step 2.10.
            //     If namedCurve is not undefined:
            //         Step 2.10.1. Let ecPrivateKey be the result of performing the parse an ASN.1
            //         structure algorithm, with data as the privateKey field of privateKeyInfo,
            //         structure as the ASN.1 ECPrivateKey structure specified in Section 3 of
            //         [RFC5915], and exactData set to true.
            //         Step 2.10.2. If an error occurred while parsing, then throw a DataError.
            //         Step 2.10.3. If the parameters field of ecPrivateKey is present, and is not
            //         an instance of the namedCurve ASN.1 type defined in [RFC5480], or does not
            //         contain the same object identifier as the parameters field of the
            //         privateKeyAlgorithm PrivateKeyAlgorithmIdentifier field of privateKeyInfo,
            //         then throw a DataError.
            //         Step 2.10.4. Let key be a new CryptoKey that represents the Elliptic Curve
            //         private key identified by performing the conversion steps defined in Section
            //         3 of [RFC5915] using ecPrivateKey.
            //     Otherwise:
            //         Step 2.10.1. Perform any key import steps defined by other applicable
            //         specifications, passing format, privateKeyInfo and obtaining namedCurve and
            //         key.
            //         Step 2.10.2. If an error occurred or there are no applicable specifications,
            //         throw a DataError.
            // Step 2.11. If namedCurve is defined, and not equal to the namedCurve member of
            // normalizedAlgorithm, throw a DataError.
            // Step 2.12. If the private key value is not a valid point on the Elliptic Curve
            // identified by the namedCurve member of normalizedAlgorithm throw a DataError.
            let handle = match normalized_algorithm.named_curve.as_str() {
                NAMED_CURVE_P256 => Handle::P256PrivateKey(
                    SecretKey::<NistP256>::from_pkcs8_der(key_data).map_err(|_| {
                        Error::Data(Some(
                            "Failed to parse the P-256 elliptic-curve private key in PKCS#8 format"
                                .into(),
                        ))
                    })?,
                ),
                NAMED_CURVE_P384 => Handle::P384PrivateKey(
                    SecretKey::<NistP384>::from_pkcs8_der(key_data).map_err(|_| {
                        Error::Data(Some(
                            "Failed to parse the P-384 elliptic-curve private key in PKCS#8 format"
                                .into(),
                        ))
                    })?,
                ),
                NAMED_CURVE_P521 => Handle::P521PrivateKey(
                    SecretKey::<NistP521>::from_pkcs8_der(key_data).map_err(|_| {
                        Error::Data(Some(
                            "Failed to parse the P-521 elliptic-curve private key in PKCS#8 format"
                                .into(),
                        ))
                    })?,
                ),
                _ => return Err(Error::Data(Some("Unsupported namedCurve".into()))),
            };

            // Step 2.13. Set the [[type]] internal slot of key to "private".
            // Step 2.14. Let algorithm be a new EcKeyAlgorithm.
            // Step 2.16. Set the namedCurve attribute of algorithm to namedCurve.
            // Step 2.17. Set the [[algorithm]] internal slot of key to algorithm.
            let algorithm = SubtleEcKeyAlgorithm {
                name: match ec_algorithm {
                    EcAlgorithm::Ecdsa => {
                        // Step 2.15. Set the name attribute of algorithm to "ECDSA".
                        CryptoAlgorithm::Ecdsa
                    },
                    EcAlgorithm::Ecdh => {
                        // Step 2.15. Set the name attribute of algorithm to "ECDH".
                        CryptoAlgorithm::Ecdh
                    },
                },
                named_curve: normalized_algorithm.named_curve.clone(),
            };
            CryptoKey::new(
                cx,
                global,
                KeyType::Private,
                extractable,
                KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm),
                usages,
                handle,
            )
        },
        KeyFormat::Jwk => {
            // Step 2.1.
            // If keyData is a JsonWebKey dictionary:
            //     Let jwk equal keyData.
            // Otherwise:
            //     Throw a DataError.
            let jwk = JsonWebKey::parse(cx, key_data)?;

            match ec_algorithm {
                EcAlgorithm::Ecdsa => {
                    // Step 2.2. If the d field is present and usages contains a value which is not
                    // "sign", or, if the d field is not present and usages contains a value which
                    // is not "verify" then throw a SyntaxError.
                    if jwk.d.is_some() && usages.iter().any(|usage| *usage != KeyUsage::Sign) {
                        return Err(Error::Syntax(Some(
                            "JWK `d` field is present and usages contains an entry \
                                which is not \"sign\""
                                .into(),
                        )));
                    }
                    if jwk.d.is_none() && usages.iter().any(|usage| *usage != KeyUsage::Verify) {
                        return Err(Error::Syntax(Some(
                            "JWK `d` field is not present and usages contains an entry \
                                which is not \"verify\""
                                .into(),
                        )));
                    }
                },
                EcAlgorithm::Ecdh => {
                    // Step 2.2. If the d field is present and if usages contains an entry which is
                    // not "deriveKey" or "deriveBits" then throw a SyntaxError. If the d field is
                    // not present and if usages is not empty then throw a SyntaxError.
                    if jwk.d.as_ref().is_some() &&
                        usages.iter().any(|usage| {
                            !matches!(usage, KeyUsage::DeriveKey | KeyUsage::DeriveBits)
                        })
                    {
                        return Err(Error::Syntax(Some(
                            "JWK `d` field is present and usages contains an entry \
                                which is not \"deriveKey\" or \"deriveBits\""
                                .into(),
                        )));
                    }
                    if jwk.d.as_ref().is_none() && !usages.is_empty() {
                        return Err(Error::Syntax(Some(
                            "JWK `d` field is not present and usages is not empty".into(),
                        )));
                    }
                },
            }

            // Step 2.3. If the kty field of jwk is not "EC", then throw a DataError.
            if jwk.kty.as_ref().is_none_or(|kty| kty != "EC") {
                return Err(Error::Data(Some("JWK `kty` field is not \"EC\"".into())));
            }

            match ec_algorithm {
                EcAlgorithm::Ecdsa => {
                    // Step 2.4. If usages is non-empty and the use field of jwk is present and is
                    // not "sig", then throw a DataError.
                    if !usages.is_empty() && jwk.use_.as_ref().is_some_and(|use_| use_ != "sig") {
                        return Err(Error::Data(Some(
                            "Usages is not empty, JWK `use` field is present, \
                                and it is not \"sign\""
                                .into(),
                        )));
                    }
                },
                EcAlgorithm::Ecdh => {
                    // Step 2.4. If usages is non-empty and the use field of jwk is present and is
                    // not equal to "enc" then throw a DataError.
                    if !usages.is_empty() && jwk.use_.as_ref().is_some_and(|use_| use_ != "enc") {
                        return Err(Error::Data(Some(
                            "Usages is not empty, JWK `use` field is present, \
                                and it is not \"enc\""
                                .into(),
                        )));
                    }
                },
            }

            // Step 2.5. If the key_ops field of jwk is present, and is invalid according to the
            // requirements of JSON Web Key [JWK], or it does not contain all of the specified
            // usages values, then throw a DataError.
            jwk.check_key_ops(&usages)?;

            // Step 2.6. If the ext field of jwk is present and has the value false and extractable
            // is true, then throw a DataError.
            if jwk.ext.is_some_and(|ext| !ext) && extractable {
                return Err(Error::Data(Some("JWK is not extractable".into())));
            }

            // Step 2.7. Let namedCurve be a string whose value is equal to the crv field of jwk.
            // Step 2.8. If namedCurve is not equal to the namedCurve member of
            // normalizedAlgorithm, throw a DataError.
            let named_curve = jwk
                .crv
                .as_ref()
                .filter(|crv| **crv == normalized_algorithm.named_curve)
                .map(|crv| crv.to_string())
                .ok_or(Error::Data(Some(
                    "JWK named curve does not match algorithm named curve".into(),
                )))?;

            // Step 2.9.
            // If namedCurve is "P-256", "P-384" or "P-521":
            let (handle, key_type) = if matches!(
                named_curve.as_str(),
                NAMED_CURVE_P256 | NAMED_CURVE_P384 | NAMED_CURVE_P521
            ) {
                if ec_algorithm == EcAlgorithm::Ecdsa {
                    // Step 2.9.1. Let algNamedCurve be a string whose initial value is undefined.
                    // Step 2.9.2.
                    // If the alg field is not present:
                    //     Let algNamedCurve be undefined.
                    // If the alg field is equal to the string "ES256":
                    //     Let algNamedCurve be the string "P-256".
                    // If the alg field is equal to the string "ES384":
                    //     Let algNamedCurve be the string "P-384".
                    // If the alg field is equal to the string "ES512":
                    //     Let algNamedCurve be the string "P-521".
                    // otherwise:
                    //     throw a DataError.
                    let alg = jwk.alg.as_ref().map(|alg| alg.to_string());
                    let alg_named_curve = match alg.as_deref() {
                        None => None,
                        Some("ES256") => Some(NAMED_CURVE_P256),
                        Some("ES384") => Some(NAMED_CURVE_P384),
                        Some("ES521") => Some(NAMED_CURVE_P521),
                        Some(alg) => {
                            return Err(Error::Data(Some(format!(
                                "Unsupported alg field in JsonWebKey: {}",
                                alg
                            ))));
                        },
                    };

                    // Step 2.9.3. If algNamedCurve is defined, and is not equal to namedCurve,
                    // throw a DataError.
                    if alg_named_curve.is_some_and(|alg_named_curve| alg_named_curve != named_curve)
                    {
                        return Err(Error::Data(Some(
                            "The algNamedCurve is defined, and is not equal to namedCurve".into(),
                        )));
                    }
                }

                // Step 2.9.4.
                // If the d field is present:
                if jwk.d.is_some() {
                    // Step 2.9.4.1. If jwk does not meet the requirements of Section 6.2.2 of JSON
                    // Web Algorithms [JWA], then throw a DataError.
                    let x = jwk.decode_required_string_field(JwkStringField::X)?;
                    let y = jwk.decode_required_string_field(JwkStringField::Y)?;
                    let d = jwk.decode_required_string_field(JwkStringField::D)?;

                    // Step 2.9.4.2. Let key be a new CryptoKey object that represents the Elliptic
                    // Curve private key identified by interpreting jwk according to Section 6.2.2
                    // of JSON Web Algorithms [JWA].
                    // NOTE: CryptoKey is created in Step 2.12 - 2.15.
                    let handle = match named_curve.as_str() {
                        NAMED_CURVE_P256 => {
                            let private_key =
                                SecretKey::<NistP256>::from_slice(&d).map_err(|_| {
                                    Error::Data(Some("Failed to parse P-256 private key".into()))
                                })?;
                            validate_public_key::<NistP256>(
                                &private_key,
                                &x_y_to_sec1_bytes(&x, &y),
                            )?;
                            Handle::P256PrivateKey(private_key)
                        },
                        NAMED_CURVE_P384 => {
                            let private_key =
                                SecretKey::<NistP384>::from_slice(&d).map_err(|_| {
                                    Error::Data(Some("Failed to parse P-384 private key".into()))
                                })?;
                            validate_public_key::<NistP384>(
                                &private_key,
                                &x_y_to_sec1_bytes(&x, &y),
                            )?;
                            Handle::P384PrivateKey(private_key)
                        },
                        NAMED_CURVE_P521 => {
                            let private_key =
                                SecretKey::<NistP521>::from_slice(&d).map_err(|_| {
                                    Error::Data(Some("Failed to parse P-521 private key".into()))
                                })?;
                            validate_public_key::<NistP521>(
                                &private_key,
                                &x_y_to_sec1_bytes(&x, &y),
                            )?;
                            Handle::P521PrivateKey(private_key)
                        },
                        _ => unreachable!(),
                    };

                    // Step 2.9.4.3. Set the [[type]] internal slot of Key to "private".
                    // NOTE: CryptoKey is created in Step 2.12 - 2.15.
                    let key_type = KeyType::Private;

                    (handle, key_type)
                }
                // Otherwise:
                else {
                    // Step 2.9.4.1. If jwk does not meet the requirements of Section 6.2.1 of JSON
                    // Web Algorithms [JWA], then throw a DataError.
                    let x = jwk.decode_required_string_field(JwkStringField::X)?;
                    let y = jwk.decode_required_string_field(JwkStringField::Y)?;

                    // Step 2.9.4.2. Let key be a new CryptoKey object that represents the Elliptic
                    // Curve public key identified by interpreting jwk according to Section 6.2.1 of
                    // JSON Web Algorithms [JWA].
                    // NOTE: CryptoKey is created in Step 2.12 - 2.15.
                    let handle = match named_curve.as_str() {
                        NAMED_CURVE_P256 => {
                            let sec1_bytes = x_y_to_sec1_bytes(&x, &y);
                            let public_key = PublicKey::<NistP256>::from_sec1_bytes(&sec1_bytes)
                                .map_err(|_| {
                                    Error::Data(Some("Failed to decode P-256 public key".into()))
                                })?;
                            Handle::P256PublicKey(public_key)
                        },
                        NAMED_CURVE_P384 => {
                            let sec1_bytes = x_y_to_sec1_bytes(&x, &y);
                            let public_key = PublicKey::<NistP384>::from_sec1_bytes(&sec1_bytes)
                                .map_err(|_| {
                                    Error::Data(Some("Failed to decode P-384 public key".into()))
                                })?;
                            Handle::P384PublicKey(public_key)
                        },
                        NAMED_CURVE_P521 => {
                            let sec1_bytes = x_y_to_sec1_bytes(&x, &y);
                            let public_key = PublicKey::<NistP521>::from_sec1_bytes(&sec1_bytes)
                                .map_err(|_| {
                                    Error::Data(Some("Failed to decode P-521 public key".into()))
                                })?;
                            Handle::P521PublicKey(public_key)
                        },
                        _ => unreachable!(),
                    };

                    // Step 2.9.4.4. Set the [[type]] internal slot of Key to "public".
                    // NOTE: CryptoKey is created in Step 2.12 - 2.15.
                    let key_type = KeyType::Public;

                    (handle, key_type)
                }
            }
            // Otherwise
            else {
                // Step 2.9.1. Perform any key import steps defined by other applicable
                // specifications, passing format, jwk and obtaining key.
                // Step 2.9.2. If an error occurred or there are no applicable specifications, throw
                // a DataError.
                // NOTE: We currently do not support applicable specifications.
                return Err(Error::NotSupported(Some("Unsupported namedCurve".into())));
            };

            // Step 2.10. If the key value is not a valid point on the Elliptic Curve identified by
            // the namedCurve member of normalizedAlgorithm throw a DataError.
            // NOTE: Done in Step 2.9.

            // Step 2.11. Let algorithm be a new instance of an EcKeyAlgorithm object.
            // Step 2.13. Set the namedCurve attribute of algorithm to namedCurve.
            // Step 2.14. Set the [[algorithm]] internal slot of key to algorithm.
            let algorithm = SubtleEcKeyAlgorithm {
                name: match ec_algorithm {
                    EcAlgorithm::Ecdsa => {
                        // Step 2.12. Set the name attribute of algorithm to "ECDSA".
                        CryptoAlgorithm::Ecdsa
                    },
                    EcAlgorithm::Ecdh => {
                        // Step 2.12. Set the name attribute of algorithm to "ECDH".
                        CryptoAlgorithm::Ecdh
                    },
                },
                named_curve,
            };
            CryptoKey::new(
                cx,
                global,
                key_type,
                extractable,
                KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm),
                usages,
                handle,
            )
        },
        KeyFormat::Raw | KeyFormat::Raw_public => {
            // Step 2.1. If the namedCurve member of normalizedAlgorithm is not a named curve, then
            // throw a DataError.
            if !SUPPORTED_CURVES
                .iter()
                .any(|&supported_curve| supported_curve == normalized_algorithm.named_curve)
            {
                return Err(Error::Data(Some("Unsupported namedCurve".into())));
            }

            match ec_algorithm {
                EcAlgorithm::Ecdsa => {
                    // Step 2.2. If usages contains a value which is not "verify" then throw a
                    // SyntaxError.
                    if usages.iter().any(|usage| *usage != KeyUsage::Verify) {
                        return Err(Error::Syntax(Some(
                            "Usages contains a value which is not \"verify\"".into(),
                        )));
                    }
                },
                EcAlgorithm::Ecdh => {
                    // Step 2.2. If usages is not the empty list, then throw a SyntaxError.
                    if !usages.is_empty() {
                        return Err(Error::Syntax(Some("Usages list is not empty".into())));
                    }
                },
            }

            // Step 2.3.
            // If namedCurve is "P-256", "P-384" or "P-521":
            let handle = if matches!(
                normalized_algorithm.named_curve.as_str(),
                NAMED_CURVE_P256 | NAMED_CURVE_P384 | NAMED_CURVE_P521
            ) {
                // Step 2.3.1. Let Q be the Elliptic Curve public key on the curve identified by
                // the namedCurve member of normalizedAlgorithm identified by performing the
                // conversion steps defined in Section 2.3.4 of [SEC1] to keyData.
                // Step 2.3.1. The uncompressed point format MUST be supported.
                // Step 2.3.1. If the implementation does not support the compressed point format
                // and a compressed point is provided, throw a DataError.
                // Step 2.3.1. If a decode error occurs or an identity point is found, throw a
                // DataError.
                match normalized_algorithm.named_curve.as_str() {
                    NAMED_CURVE_P256 => {
                        let q = PublicKey::<NistP256>::from_sec1_bytes(key_data).map_err(|_| {
                            Error::Data(Some("Failed to decode P-256 public key".into()))
                        })?;
                        Handle::P256PublicKey(q)
                    },
                    NAMED_CURVE_P384 => {
                        let q = PublicKey::<NistP384>::from_sec1_bytes(key_data).map_err(|_| {
                            Error::Data(Some("Failed to decode P-384 public key".into()))
                        })?;
                        Handle::P384PublicKey(q)
                    },
                    NAMED_CURVE_P521 => {
                        let q = PublicKey::<NistP521>::from_sec1_bytes(key_data).map_err(|_| {
                            Error::Data(Some("Failed to decode P-521 public key".into()))
                        })?;
                        Handle::P521PublicKey(q)
                    },
                    _ => unreachable!(),
                }

                // Step 2.3.1. Let key be a new CryptoKey that represents Q.
                // NOTE: CryptoKey is created in Step 2.7 - 2.8.
            }
            // Otherwise:
            else {
                // Step. 2.3.1. Perform any key import steps defined by other applicable
                // specifications, passing format, keyData and obtaining key.
                // Step. 2.3.2. If an error occurred or there are no applicable specifications,
                // throw a DataError.
                // NOTE: We currently do not support applicable specifications.
                return Err(Error::NotSupported(Some("Unsupported namedCurve".into())));
            };

            // Step 2.4. Let algorithm be a new EcKeyAlgorithm object.
            // Step 2.6. Set the namedCurve attribute of algorithm to equal the namedCurve member
            // of normalizedAlgorithm.
            let algorithm = SubtleEcKeyAlgorithm {
                name: match ec_algorithm {
                    EcAlgorithm::Ecdsa => {
                        // Step 2.5. Set the name attribute of algorithm to "ECDSA".
                        CryptoAlgorithm::Ecdsa
                    },
                    EcAlgorithm::Ecdh => {
                        // Step 2.5. Set the name attribute of algorithm to "ECDH".
                        CryptoAlgorithm::Ecdh
                    },
                },
                named_curve: normalized_algorithm.named_curve.clone(),
            };

            // Step 2.7. Set the [[type]] internal slot of key to "public"
            // Step 2.8. Set the [[algorithm]] internal slot of key to algorithm.
            CryptoKey::new(
                cx,
                global,
                KeyType::Public,
                extractable,
                KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm),
                usages,
                handle,
            )
        },
        // Otherwise:
        _ => {
            // throw a NotSupportedError.
            return Err(Error::NotSupported(Some("Unsupported key format".into())));
        },
    };

    // Step 3. Return key.
    Ok(key)
}

/// <https://w3c.github.io/webcrypto/#ecdsa-operations-export-key>
/// <https://w3c.github.io/webcrypto/#ecdh-operations-export-key>
pub(crate) fn export_key(format: KeyFormat, key: &CryptoKey) -> Result<ExportedKey, Error> {
    // Step 1. Let key be the CryptoKey to be exported.

    // Step 2. If the underlying cryptographic key material represented by the [[handle]] internal
    // slot of key cannot be accessed, then throw an OperationError.
    // NOTE: Done in Step 3.

    // Step 3.
    let result = match format {
        // If format is "spki":
        KeyFormat::Spki => {
            // Step 3.1. If the [[type]] internal slot of key is not "public", then throw an
            // InvalidAccessError.
            if key.Type() != KeyType::Public {
                return Err(Error::InvalidAccess(Some(
                    "[[type]] internal slot of key is not \"public\"".into(),
                )));
            }

            // Step 3.2.
            // Let data be an instance of the SubjectPublicKeyInfo ASN.1 structure defined in
            // [RFC5280] with the following properties:
            //     * Set the algorithm field to an AlgorithmIdentifier ASN.1 type with the
            //       following properties:
            //         * Set the algorithm field to the OID id-ecPublicKey defined in [RFC5480].
            //         * Set the parameters field to an instance of the ECParameters ASN.1 type
            //           defined in [RFC5480] as follows:
            //             If the namedCurve attribute of the [[algorithm]] internal slot of key is
            //             "P-256", "P-384" or "P-521":
            //                 Let keyData be the byte sequence that represents the Elliptic Curve
            //                 public key represented by the [[handle]] internal slot of key
            //                 according to the encoding rules specified in Section 2.2 of
            //                 [RFC5480] and using the uncompressed form. and keyData.
            //                     If the namedCurve attribute of the [[algorithm]] internal slot
            //                     of key is "P-256":
            //                         Set parameters to the namedCurve choice with value equal to
            //                         the object identifier secp256r1 defined in [RFC5480]
            //                     If the namedCurve attribute of the [[algorithm]] internal slot
            //                     of key is "P-384":
            //                         Set parameters to the namedCurve choice with value equal to
            //                         the object identifier secp384r1 defined in [RFC5480]
            //                     If the namedCurve attribute of the [[algorithm]] internal slot
            //                     of key is "P-521":
            //                         Set parameters to the namedCurve choice with value equal to
            //                         the object identifier secp521r1 defined in [RFC5480]
            //             Otherwise:
            //                 1. Perform any key export steps defined by other applicable
            //                    specifications, passing format and the namedCurve attribute of
            //                    the [[algorithm]] internal slot of key and obtaining
            //                    namedCurveOid and keyData.
            //                 2. Set parameters to the namedCurve choice with value equal to the
            //                    object identifier namedCurveOid.
            //     * Set the subjectPublicKey field to keyData.
            // NOTE: We currently do not support other applicable specifications.
            let data = match key.handle() {
                Handle::P256PublicKey(public_key) => public_key.to_public_key_der(),
                Handle::P384PublicKey(public_key) => public_key.to_public_key_der(),
                Handle::P521PublicKey(public_key) => public_key.to_public_key_der(),
                _ => {
                    return Err(Error::Operation(Some(
                        "The key is not an elliptic curve public key".into(),
                    )));
                },
            }
            .map_err(|_| {
                Error::Operation(Some("Failed to export elliptic curve public key".into()))
            })?;

            // Step 3.3. Let result be the result of DER-encoding data.
            ExportedKey::new_bytes(data.to_vec())
        },
        // If format is "pkcs8":
        KeyFormat::Pkcs8 => {
            // Step 3.1. If the [[type]] internal slot of key is not "private", then throw an
            // InvalidAccessError.
            if key.Type() != KeyType::Private {
                return Err(Error::InvalidAccess(Some(
                    "[[type]] internal slot of key is not \"private\"".into(),
                )));
            }

            // Step 3.2.
            // Let data be an instance of the PrivateKeyInfo ASN.1 structure defined in [RFC5208]
            // with the following properties:
            //     * Set the version field to 0.
            //     * Set the privateKeyAlgorithm field to a PrivateKeyAlgorithmIdentifier ASN.1
            //       type with the following properties:
            //         * Set the algorithm field to the OID id-ecPublicKey defined in [RFC5480].
            //         * Set the parameters field to an instance of the ECParameters ASN.1 type
            //           defined in [RFC5480] as follows:
            //             If the namedCurve attribute of the [[algorithm]] internal slot of key is
            //             "P-256", "P-384" or "P-521":
            //                 Let keyData be the result of DER-encoding an instance of the
            //                 ECPrivateKey structure defined in Section 3 of [RFC5915] for the
            //                 Elliptic Curve private key represented by the [[handle]] internal
            //                 slot of key and that conforms to the following:
            //                     * The parameters field is present, and is equivalent to the
            //                       parameters field of the privateKeyAlgorithm field of this
            //                       PrivateKeyInfo ASN.1 structure.
            //                     * The publicKey field is present and represents the Elliptic
            //                       Curve public key associated with the Elliptic Curve private key
            //                       represented by the [[handle]] internal slot of key.
            //                     * If the namedCurve attribute of the [[algorithm]] internal slot
            //                       of key is "P-256":
            //                         Set parameters to the namedCurve choice with value equal to
            //                         the object identifier secp256r1 defined in [RFC5480]
            //                     * If the namedCurve attribute of the [[algorithm]] internal slot
            //                       of key is "P-384":
            //                         Set parameters to the namedCurve choice with value equal to
            //                         the object identifier secp384r1 defined in [RFC5480]
            //                     * If the namedCurve attribute of the [[algorithm]] internal slot
            //                       of key is "P-521":
            //                         Set parameters to the namedCurve choice with value equal to
            //                         the object identifier secp521r1 defined in [RFC5480]
            //             Otherwise:
            //                 1. Perform any key export steps defined by other applicable
            //                    specifications, passing format and the namedCurve attribute of
            //                    the [[algorithm]] internal slot of key and obtaining
            //                    namedCurveOid and keyData.
            //                 2. Set parameters to the namedCurve choice with value equal to the
            //                    object identifier namedCurveOid.
            //     * Set the privateKey field to keyData.
            // NOTE: We currently do not support other applicable specifications.
            let data = match key.handle() {
                Handle::P256PrivateKey(private_key) => private_key.to_pkcs8_der(),
                Handle::P384PrivateKey(private_key) => private_key.to_pkcs8_der(),
                Handle::P521PrivateKey(private_key) => private_key.to_pkcs8_der(),
                _ => {
                    return Err(Error::Operation(Some(
                        "The key is not an elliptic curve public key".into(),
                    )));
                },
            }
            .map_err(|_| {
                Error::Operation(Some("Failed to export elliptic curve private key".into()))
            })?;

            // Step 3.3. Let result be the result of DER-encoding data.
            ExportedKey::new_bytes(data.as_bytes().to_vec())
        },
        // If format is "jwk":
        KeyFormat::Jwk => {
            // Step 3.1. Let jwk be a new JsonWebKey dictionary.
            let mut jwk = JsonWebKey::default();

            // Step 3.2. Set the kty attribute of jwk to "EC".
            jwk.kty = Some(DOMString::from("EC"));

            // Step 3.3.
            let KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm) = key.algorithm() else {
                return Err(Error::Operation(Some(
                    "The key is not an elliptic curve key".into(),
                )));
            };
            // If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256",
            // "P-384" or "P-521":
            if matches!(
                algorithm.named_curve.as_str(),
                NAMED_CURVE_P256 | NAMED_CURVE_P384 | NAMED_CURVE_P521
            ) {
                // Step 3.3.1.
                // If the namedCurve attribute of the [[algorithm]] internal slot of key is
                // "P-256":
                //     Set the crv attribute of jwk to "P-256"
                // If the namedCurve attribute of the [[algorithm]] internal slot of key is
                // "P-384":
                //     Set the crv attribute of jwk to "P-384"
                // If the namedCurve attribute of the [[algorithm]] internal slot of key is
                // "P-521":
                //     Set the crv attribute of jwk to "P-521"
                jwk.crv = Some(DOMString::from(algorithm.named_curve.as_str()));

                // Step 3.3.2. Set the x attribute of jwk according to the definition in Section
                // 6.2.1.2 of JSON Web Algorithms [JWA].
                // Step 3.3.3. Set the y attribute of jwk according to the definition in Section
                // 6.2.1.3 of JSON Web Algorithms [JWA].
                let extraction_error = || {
                    Error::Operation(Some(
                        "Failed to extract encoded point from elliptic curve key".into(),
                    ))
                };
                let (x, y) = match key.handle() {
                    Handle::P256PublicKey(public_key) => {
                        let encoded_point = public_key.to_sec1_point(false);
                        (
                            encoded_point.x().ok_or(extraction_error())?.to_vec(),
                            encoded_point.y().ok_or(extraction_error())?.to_vec(),
                        )
                    },
                    Handle::P384PublicKey(public_key) => {
                        let encoded_point = public_key.to_sec1_point(false);
                        (
                            encoded_point.x().ok_or(extraction_error())?.to_vec(),
                            encoded_point.y().ok_or(extraction_error())?.to_vec(),
                        )
                    },
                    Handle::P521PublicKey(public_key) => {
                        let encoded_point = public_key.to_sec1_point(false);
                        (
                            encoded_point.x().ok_or(extraction_error())?.to_vec(),
                            encoded_point.y().ok_or(extraction_error())?.to_vec(),
                        )
                    },
                    Handle::P256PrivateKey(private_key) => {
                        let public_key = private_key.public_key();
                        let encoded_point = public_key.to_sec1_point(false);
                        (
                            encoded_point.x().ok_or(extraction_error())?.to_vec(),
                            encoded_point.y().ok_or(extraction_error())?.to_vec(),
                        )
                    },
                    Handle::P384PrivateKey(private_key) => {
                        let public_key = private_key.public_key();
                        let encoded_point = public_key.to_sec1_point(false);
                        (
                            encoded_point.x().ok_or(extraction_error())?.to_vec(),
                            encoded_point.y().ok_or(extraction_error())?.to_vec(),
                        )
                    },
                    Handle::P521PrivateKey(private_key) => {
                        let public_key = private_key.public_key();
                        let encoded_point = public_key.to_sec1_point(false);
                        (
                            encoded_point.x().ok_or(extraction_error())?.to_vec(),
                            encoded_point.y().ok_or(extraction_error())?.to_vec(),
                        )
                    },
                    _ => {
                        return Err(Error::Operation(Some(
                            "The key is not an elliptic curve key".into(),
                        )));
                    },
                };
                jwk.encode_string_field(JwkStringField::X, &x);
                jwk.encode_string_field(JwkStringField::Y, &y);

                // Step 3.3.4.
                // If the [[type]] internal slot of key is "private"
                //     Set the d attribute of jwk according to the definition in Section 6.2.2.1 of
                //     JSON Web Algorithms [JWA].
                if key.Type() == KeyType::Private {
                    let d = match key.handle() {
                        Handle::P256PrivateKey(private_key) => {
                            private_key.to_bytes().as_slice().to_vec()
                        },
                        Handle::P384PrivateKey(private_key) => {
                            private_key.to_bytes().as_slice().to_vec()
                        },
                        Handle::P521PrivateKey(private_key) => {
                            private_key.to_bytes().as_slice().to_vec()
                        },
                        _ => {
                            return Err(Error::Operation(Some(
                                "The key is not an elliptic curve private key".into(),
                            )));
                        },
                    };
                    jwk.encode_string_field(JwkStringField::D, &d);
                }
            }
            // Otherwise:
            else {
                // Step 3.3.1. Perform any key export steps defined by other applicable
                // specifications, passing format and the namedCurve attribute of the [[algorithm]]
                // internal slot of key and obtaining namedCurve and a new value of jwk.
                // Step 3.3.2. Set the crv attribute of jwk to namedCurve.
                // NOTE: We currently do not support other applicable specifications.
                return Err(Error::NotSupported(Some("Unsupported named curve".into())));
            }

            // Step 3.4. Set the key_ops attribute of jwk to the usages attribute of key.
            jwk.set_key_ops(&key.usages());

            // Step 3.4. Set the ext attribute of jwk to the [[extractable]] internal slot of key.
            jwk.ext = Some(key.Extractable());

            // Step 3.4. Let result be jwk.
            ExportedKey::new_jwk(jwk)
        },
        // If format is "raw":
        KeyFormat::Raw | KeyFormat::Raw_public => {
            // Step 3.1. If the [[type]] internal slot of key is not "public", then throw an
            // InvalidAccessError.
            if key.Type() != KeyType::Public {
                return Err(Error::InvalidAccess(Some(
                    "[[type]] internal slot of key is not \"public\"".into(),
                )));
            }

            // Step 3.2.
            // If the namedCurve attribute of the [[algorithm]] internal slot of key is "P-256",
            // "P-384" or "P-521":
            //     Let data be a byte sequence representing the Elliptic Curve point Q represented
            //     by the [[handle]] internal slot of key according to [SEC1] 2.3.3 using the
            //     uncompressed format.
            // Otherwise:
            //     Perform any key export steps defined by other applicable specifications, passing
            //     format and the namedCurve attribute of the [[algorithm]] internal slot of key
            //     and obtaining namedCurve and data.
            //     NOTE: We currently do not support other applicable specifications.
            let KeyAlgorithmAndDerivatives::EcKeyAlgorithm(algorithm) = key.algorithm() else {
                return Err(Error::Operation(Some(
                    "The key is not an elliptic curve key".into(),
                )));
            };
            let data = if matches!(
                algorithm.named_curve.as_str(),
                NAMED_CURVE_P256 | NAMED_CURVE_P384 | NAMED_CURVE_P521
            ) {
                match key.handle() {
                    Handle::P256PublicKey(public_key) => public_key.to_sec1_bytes().to_vec(),
                    Handle::P384PublicKey(public_key) => public_key.to_sec1_bytes().to_vec(),
                    Handle::P521PublicKey(public_key) => public_key.to_sec1_bytes().to_vec(),
                    _ => {
                        return Err(Error::Operation(Some(
                            "The key is not an elliptic curve public key".into(),
                        )));
                    },
                }
            } else {
                return Err(Error::NotSupported(Some("Unsupported named curve".into())));
            };

            // Step 3.3. Let result be data.
            ExportedKey::new_bytes(data)
        },
        // Otherwise:
        _ => {
            // throw a NotSupportedError.
            return Err(Error::NotSupported(Some("Unsupported key format".into())));
        },
    };

    // Step 4. Return result.
    Ok(result)
}

/// <https://wicg.github.io/webcrypto-modern-algos/#SubtleCrypto-method-getPublicKey>
/// Step 9 - 15, for elliptic curve cryptography
pub(crate) fn get_public_key(
    cx: &mut JSContext,
    global: &GlobalScope,
    key: &CryptoKey,
    algorithm: &KeyAlgorithmAndDerivatives,
    usages: Vec<KeyUsage>,
) -> Result<DomRoot<CryptoKey>, Error> {
    // Step 9. If usages contains an entry which is not supported for a public key by the algorithm
    // identified by algorithm, then throw a SyntaxError.
    //
    // NOTE: See "importKey" operation for supported usages
    if usages.iter().any(|usage| *usage != KeyUsage::Verify) {
        return Err(Error::Syntax(Some(
            "Usages contains an entry which is not \"verify\"".to_string(),
        )));
    }

    // Step 10. Let publicKey be a new CryptoKey representing the public key corresponding to the
    // private key represented by the [[handle]] internal slot of key.
    // Step 11. If an error occurred, then throw a OperationError.
    // Step 12. Set the [[type]] internal slot of publicKey to "public".
    // Step 13. Set the [[algorithm]] internal slot of publicKey to algorithm.
    // Step 14. Set the [[extractable]] internal slot of publicKey to true.
    // Step 15. Set the [[usages]] internal slot of publicKey to usages.
    let public_key_handle = match key.handle() {
        Handle::P256PrivateKey(private_key) => Handle::P256PublicKey(private_key.public_key()),
        Handle::P384PrivateKey(private_key) => Handle::P384PublicKey(private_key.public_key()),
        Handle::P521PrivateKey(private_key) => Handle::P521PublicKey(private_key.public_key()),
        _ => {
            return Err(Error::Operation(Some(
                "[[handle]] internal slot of key is not an elliptic curve private key".to_string(),
            )));
        },
    };
    let public_key = CryptoKey::new(
        cx,
        global,
        KeyType::Public,
        true,
        algorithm.clone(),
        usages,
        public_key_handle,
    );

    Ok(public_key)
}

/// Concatenate big endian serialized coordinates of an elliptic curve point, to form an
/// uncompressed SEC1 encoded curve point, with prefix `0x04` indicating it is an uncompressed
/// point.
fn x_y_to_sec1_bytes(x: &[u8], y: &[u8]) -> Vec<u8> {
    let mut sec1_bytes = Vec::with_capacity(1 + x.len() + y.len());
    sec1_bytes.push(4u8);
    sec1_bytes.extend_from_slice(x);
    sec1_bytes.extend_from_slice(y);
    sec1_bytes
}

/// Validate the public key in form of uncompressed SEC1 encoded curve point, against a private key.
fn validate_public_key<C>(private_key: &SecretKey<C>, sec1_bytes: &[u8]) -> ErrorResult
where
    C: Curve + ValidatePublicKey,
    FieldBytesSize<C>: ModulusSize,
{
    let sec1_point = Sec1Point::<C>::from_bytes(sec1_bytes)
        .map_err(|_| Error::Data(Some("Failed to encode curve point".into())))?;
    C::validate_public_key(private_key, &sec1_point)
        .map_err(|_| Error::Data(Some("The public key does not match the private key".into())))
}