/**
 * Encode a 32-byte P-256 secret scalar as DER `ECPrivateKey` per
 * RFC 5915 §3. Output length is exactly 51 bytes; version is 1, the
 * named-curve OID for secp256r1 (`1.2.840.10045.3.1.7`,
 * SP 800-186 §3.2.1.3) is included in `parameters [0]`, and the
 * `publicKey [1]` field is omitted.
 *
 * Byte-stable: same input scalar produces byte-identical output. No
 * canonicalisation pass needed because every field has a single legal
 * DER encoding under the strict-DER rules of X.690 §10.
 *
 * @throws TypeError if `scalar` is not a Uint8Array
 * @throws RangeError if `scalar.length !== 32`
 */
export declare function encodeEcPrivateKey(scalar: Uint8Array): Uint8Array;
/**
 * Decode a DER `ECPrivateKey` (RFC 5915 §3) and return the 32-byte
 * raw P-256 secret scalar.
 *
 * Strict-DER per X.690 §10 (Restrictions on the BER). Rejects the
 * cases enumerated in the file-level header. Accepts (and ignores)
 * an optional `publicKey [1]` field per RFC 5915 §3 lenient input;
 * the scalar is the only return value.
 *
 * Any curve OID inside `parameters [0]` other than secp256r1
 * (`1.2.840.10045.3.1.7`) is rejected. Decoders that need other
 * curves must use a different parser; this library is P-256 only.
 *
 * @throws TypeError if `der` is not a Uint8Array
 * @throws Error on any DER syntax violation or unsupported parameter
 */
export declare function decodeEcPrivateKey(der: Uint8Array): Uint8Array;