// invalid points and the point at infinity, and NewPrivateKey rejects
	// invalid scalars and the zero value. BytesX returns an error for the point
	// at infinity, but in a prime order group such as the NIST curves that can
	// only be the result of a scalar multiplication if one of the inputs is the
	// zero scalar or the point at infinity.

	if boring.Enabled {
		return boring.ECDH(local.boring, remote.boring)
	}

// functions for hashing bytes to arbitrary-length output.
//
//
// SHAKE implementation is based on FIPS PUB 202 [1]
// cSHAKE implementations is based on NIST SP 800-185 [2]
//
// [1] https://nvlpubs.nist.gov/nistpubs/FIPS/NIST.FIPS.202.pdf
// [2] https://doi.org/10.6028/NIST.SP.800-185

import (
	"encoding/binary"
	"hash"
	"io"
)

// ShakeHash defines the interface to hash functions that support

//	EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
// See FIPS 197 for specification, and see Daemen and Rijmen's Rijndael submission
// for implementation details.
//	https://csrc.nist.gov/csrc/media/publications/fips/197/final/documents/fips-197.pdf
//	https://csrc.nist.gov/archive/aes/rijndael/Rijndael-ammended.pdf

package aes

import "internal/byteorder"

// Encrypt one block from src into dst, using the expanded key xk.

	// of the rate, which involves adding a "1" bit, zero or more "0" bits, and
	// a final "1" bit. We merge the first "1" bit from the padding into dsbyte,
	// giving 00000110b (0x06) and 00011111b (0x1f).
	// [1] http://csrc.nist.gov/publications/drafts/fips-202/fips_202_draft.pdf
	//     "Draft FIPS 202: SHA-3 Standard: Permutation-Based Hash and
	//      Extendable-Output Functions (May 2014)"
	dsbyte byte

	HasVX     bool // vector facility. Note: the runtime sets this when it processes auxv records.
	HasVXE    bool // vector-enhancements facility 1
	HasKDSA   bool // elliptic curve functions
	HasECDSA  bool // NIST curves
	HasEDDSA  bool // Edwards curves
	_         CacheLinePad
}

// CPU feature variables are accessed by assembly code in various packages.
//go:linkname X86
//go:linkname ARM
//go:linkname ARM64