package chacha20poly1305

Import Path
	vendor/golang.org/x/crypto/chacha20poly1305 (on go.dev)

Dependency Relation
	imports 7 packages, and imported by one package

Involved Source Files

	  d chacha20poly1305.go
		Package chacha20poly1305 implements the ChaCha20-Poly1305 AEAD and its
		extended nonce variant XChaCha20-Poly1305, as specified in RFC 8439 and
		draft-irtf-cfrg-xchacha-01.

	    chacha20poly1305_amd64.go
	    chacha20poly1305_generic.go
	    xchacha20poly1305.go
	    chacha20poly1305_amd64.s
Package-Level Type Names (total 2, neither is exported)

	/* sort exporteds by: alphabet | popularity */
	/* 2 unexporteds ... *//* 2 unexporteds: */
	 type chacha20poly1305 (struct)

		Fields (only one, which is unexported)
			/* one unexported ... *//* one unexported: */
			key [32]byte
		Methods (total 8, in which 4 are exported)
			(*chacha20poly1305) NonceSize() int
			(*chacha20poly1305) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error)
			(*chacha20poly1305) Overhead() int
			(*chacha20poly1305) Seal(dst, nonce, plaintext, additionalData []byte) []byte
			/* 4 unexporteds ... *//* 4 unexporteds: */
			(*chacha20poly1305) open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error)
			(*chacha20poly1305) openGeneric(dst, nonce, ciphertext, additionalData []byte) ([]byte, error)
			(*chacha20poly1305) seal(dst, nonce, plaintext, additionalData []byte) []byte
			(*chacha20poly1305) sealGeneric(dst, nonce, plaintext, additionalData []byte) []byte
		Implements (at least one exported)
			*chacha20poly1305 : crypto/cipher.AEAD

	 type xchacha20poly1305 (struct)

		Fields (only one, which is unexported)
			/* one unexported ... *//* one unexported: */
			key [32]byte
		Methods (total 4, all are exported)
			(*xchacha20poly1305) NonceSize() int
			(*xchacha20poly1305) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error)
			(*xchacha20poly1305) Overhead() int
			(*xchacha20poly1305) Seal(dst, nonce, plaintext, additionalData []byte) []byte
		Implements (at least one exported)
			*xchacha20poly1305 : crypto/cipher.AEAD


Package-Level Functions (total 8, in which 2 are exported)

	 func New(key []byte) (cipher.AEAD, error)
		New returns a ChaCha20-Poly1305 AEAD that uses the given 256-bit key.

	 func NewX(key []byte) (cipher.AEAD, error)
		NewX returns a XChaCha20-Poly1305 AEAD that uses the given 256-bit key.
		
		XChaCha20-Poly1305 is a ChaCha20-Poly1305 variant that takes a longer nonce,
		suitable to be generated randomly without risk of collisions. It should be
		preferred when nonce uniqueness cannot be trivially ensured, or whenever
		nonces are randomly generated.

	/* 6 unexporteds ... *//* 6 unexporteds: */
	 func chacha20Poly1305Open(dst []byte, key []uint32, src, ad []byte) bool
	 func chacha20Poly1305Seal(dst []byte, key []uint32, src, ad []byte)
	 func setupState(state *[16]uint32, key *[32]byte, nonce []byte)
		setupState writes a ChaCha20 input matrix to state. See
		https://tools.ietf.org/html/rfc7539#section-2.3.

	 func sliceForAppend(in []byte, n int) (head, tail []byte)
		sliceForAppend takes a slice and a requested number of bytes. It returns a
		slice with the contents of the given slice followed by that many bytes and a
		second slice that aliases into it and contains only the extra bytes. If the
		original slice has sufficient capacity then no allocation is performed.

	 func writeUint64(p *poly1305.MAC, n int)
	 func writeWithPadding(p *poly1305.MAC, b []byte)
Package-Level Variables (total 2, neither is exported)

	/* 2 unexporteds ... *//* 2 unexporteds: */
	  var errOpen error
	  var useAVX2 bool
Package-Level Constants (total 4, all are exported)

	const KeySize = 32
		KeySize is the size of the key used by this AEAD, in bytes.

	const NonceSize = 12
		NonceSize is the size of the nonce used with the standard variant of this
		AEAD, in bytes.
		
		Note that this is too short to be safely generated at random if the same
		key is reused more than 2³² times.

	const NonceSizeX = 24
		NonceSizeX is the size of the nonce used with the XChaCha20-Poly1305
		variant of this AEAD, in bytes.

	const Overhead = 16
		Overhead is the size of the Poly1305 authentication tag, and the
		difference between a ciphertext length and its plaintext.

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