Upgrading dependencies to include logrus.

vendor/golang.org/x/crypto/chacha20poly1305/xchacha20poly1305.go

@@ -0,0 +1,104 @@
+// Copyright 2018 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package chacha20poly1305
+
+import (
+	"crypto/cipher"
+	"encoding/binary"
+	"errors"
+
+	"golang.org/x/crypto/internal/chacha20"
+)
+
+type xchacha20poly1305 struct {
+	key [8]uint32
+}
+
+// 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.
+func NewX(key []byte) (cipher.AEAD, error) {
+	if len(key) != KeySize {
+		return nil, errors.New("chacha20poly1305: bad key length")
+	}
+	ret := new(xchacha20poly1305)
+	ret.key[0] = binary.LittleEndian.Uint32(key[0:4])
+	ret.key[1] = binary.LittleEndian.Uint32(key[4:8])
+	ret.key[2] = binary.LittleEndian.Uint32(key[8:12])
+	ret.key[3] = binary.LittleEndian.Uint32(key[12:16])
+	ret.key[4] = binary.LittleEndian.Uint32(key[16:20])
+	ret.key[5] = binary.LittleEndian.Uint32(key[20:24])
+	ret.key[6] = binary.LittleEndian.Uint32(key[24:28])
+	ret.key[7] = binary.LittleEndian.Uint32(key[28:32])
+	return ret, nil
+}
+
+func (*xchacha20poly1305) NonceSize() int {
+	return NonceSizeX
+}
+
+func (*xchacha20poly1305) Overhead() int {
+	return 16
+}
+
+func (x *xchacha20poly1305) Seal(dst, nonce, plaintext, additionalData []byte) []byte {
+	if len(nonce) != NonceSizeX {
+		panic("chacha20poly1305: bad nonce length passed to Seal")
+	}
+
+	// XChaCha20-Poly1305 technically supports a 64-bit counter, so there is no
+	// size limit. However, since we reuse the ChaCha20-Poly1305 implementation,
+	// the second half of the counter is not available. This is unlikely to be
+	// an issue because the cipher.AEAD API requires the entire message to be in
+	// memory, and the counter overflows at 256 GB.
+	if uint64(len(plaintext)) > (1<<38)-64 {
+		panic("chacha20poly1305: plaintext too large")
+	}
+
+	hNonce := [4]uint32{
+		binary.LittleEndian.Uint32(nonce[0:4]),
+		binary.LittleEndian.Uint32(nonce[4:8]),
+		binary.LittleEndian.Uint32(nonce[8:12]),
+		binary.LittleEndian.Uint32(nonce[12:16]),
+	}
+	c := &chacha20poly1305{
+		key: chacha20.HChaCha20(&x.key, &hNonce),
+	}
+	// The first 4 bytes of the final nonce are unused counter space.
+	cNonce := make([]byte, NonceSize)
+	copy(cNonce[4:12], nonce[16:24])
+
+	return c.seal(dst, cNonce[:], plaintext, additionalData)
+}
+
+func (x *xchacha20poly1305) Open(dst, nonce, ciphertext, additionalData []byte) ([]byte, error) {
+	if len(nonce) != NonceSizeX {
+		panic("chacha20poly1305: bad nonce length passed to Open")
+	}
+	if len(ciphertext) < 16 {
+		return nil, errOpen
+	}
+	if uint64(len(ciphertext)) > (1<<38)-48 {
+		panic("chacha20poly1305: ciphertext too large")
+	}
+
+	hNonce := [4]uint32{
+		binary.LittleEndian.Uint32(nonce[0:4]),
+		binary.LittleEndian.Uint32(nonce[4:8]),
+		binary.LittleEndian.Uint32(nonce[8:12]),
+		binary.LittleEndian.Uint32(nonce[12:16]),
+	}
+	c := &chacha20poly1305{
+		key: chacha20.HChaCha20(&x.key, &hNonce),
+	}
+	// The first 4 bytes of the final nonce are unused counter space.
+	cNonce := make([]byte, NonceSize)
+	copy(cNonce[4:12], nonce[16:24])
+
+	return c.open(dst, cNonce[:], ciphertext, additionalData)
+}