1 files changed, 198 insertions, 0 deletions
diff --git a/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go b/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go
new file mode 100644
index 00000000..0f8efdba
--- /dev/null
+++ b/vendor/golang.org/x/crypto/internal/chacha20/chacha_generic.go
@@ -0,0 +1,198 @@
+// Copyright 2016 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 ChaCha20 implements the core ChaCha20 function as specified in https://tools.ietf.org/html/rfc7539#section-2.3.
+package chacha20
+
+import "encoding/binary"
+
+const rounds = 20
+
+// core applies the ChaCha20 core function to 16-byte input in, 32-byte key k,
+// and 16-byte constant c, and puts the result into 64-byte array out.
+func core(out *[64]byte, in *[16]byte, k *[32]byte) {
+	j0 := uint32(0x61707865)
+	j1 := uint32(0x3320646e)
+	j2 := uint32(0x79622d32)
+	j3 := uint32(0x6b206574)
+	j4 := binary.LittleEndian.Uint32(k[0:4])
+	j5 := binary.LittleEndian.Uint32(k[4:8])
+	j6 := binary.LittleEndian.Uint32(k[8:12])
+	j7 := binary.LittleEndian.Uint32(k[12:16])
+	j8 := binary.LittleEndian.Uint32(k[16:20])
+	j9 := binary.LittleEndian.Uint32(k[20:24])
+	j10 := binary.LittleEndian.Uint32(k[24:28])
+	j11 := binary.LittleEndian.Uint32(k[28:32])
+	j12 := binary.LittleEndian.Uint32(in[0:4])
+	j13 := binary.LittleEndian.Uint32(in[4:8])
+	j14 := binary.LittleEndian.Uint32(in[8:12])
+	j15 := binary.LittleEndian.Uint32(in[12:16])
+
+	x0, x1, x2, x3, x4, x5, x6, x7 := j0, j1, j2, j3, j4, j5, j6, j7
+	x8, x9, x10, x11, x12, x13, x14, x15 := j8, j9, j10, j11, j12, j13, j14, j15
+
+	for i := 0; i < rounds; i += 2 {
+		x0 += x4
+		x12 ^= x0
+		x12 = (x12 << 16) | (x12 >> (16))
+		x8 += x12
+		x4 ^= x8
+		x4 = (x4 << 12) | (x4 >> (20))
+		x0 += x4
+		x12 ^= x0
+		x12 = (x12 << 8) | (x12 >> (24))
+		x8 += x12
+		x4 ^= x8
+		x4 = (x4 << 7) | (x4 >> (25))
+		x1 += x5
+		x13 ^= x1
+		x13 = (x13 << 16) | (x13 >> 16)
+		x9 += x13
+		x5 ^= x9
+		x5 = (x5 << 12) | (x5 >> 20)
+		x1 += x5
+		x13 ^= x1
+		x13 = (x13 << 8) | (x13 >> 24)
+		x9 += x13
+		x5 ^= x9
+		x5 = (x5 << 7) | (x5 >> 25)
+		x2 += x6
+		x14 ^= x2
+		x14 = (x14 << 16) | (x14 >> 16)
+		x10 += x14
+		x6 ^= x10
+		x6 = (x6 << 12) | (x6 >> 20)
+		x2 += x6
+		x14 ^= x2
+		x14 = (x14 << 8) | (x14 >> 24)
+		x10 += x14
+		x6 ^= x10
+		x6 = (x6 << 7) | (x6 >> 25)
+		x3 += x7
+		x15 ^= x3
+		x15 = (x15 << 16) | (x15 >> 16)
+		x11 += x15
+		x7 ^= x11
+		x7 = (x7 << 12) | (x7 >> 20)
+		x3 += x7
+		x15 ^= x3
+		x15 = (x15 << 8) | (x15 >> 24)
+		x11 += x15
+		x7 ^= x11
+		x7 = (x7 << 7) | (x7 >> 25)
+		x0 += x5
+		x15 ^= x0
+		x15 = (x15 << 16) | (x15 >> 16)
+		x10 += x15
+		x5 ^= x10
+		x5 = (x5 << 12) | (x5 >> 20)
+		x0 += x5
+		x15 ^= x0
+		x15 = (x15 << 8) | (x15 >> 24)
+		x10 += x15
+		x5 ^= x10
+		x5 = (x5 << 7) | (x5 >> 25)
+		x1 += x6
+		x12 ^= x1
+		x12 = (x12 << 16) | (x12 >> 16)
+		x11 += x12
+		x6 ^= x11
+		x6 = (x6 << 12) | (x6 >> 20)
+		x1 += x6
+		x12 ^= x1
+		x12 = (x12 << 8) | (x12 >> 24)
+		x11 += x12
+		x6 ^= x11
+		x6 = (x6 << 7) | (x6 >> 25)
+		x2 += x7
+		x13 ^= x2
+		x13 = (x13 << 16) | (x13 >> 16)
+		x8 += x13
+		x7 ^= x8
+		x7 = (x7 << 12) | (x7 >> 20)
+		x2 += x7
+		x13 ^= x2
+		x13 = (x13 << 8) | (x13 >> 24)
+		x8 += x13
+		x7 ^= x8
+		x7 = (x7 << 7) | (x7 >> 25)
+		x3 += x4
+		x14 ^= x3
+		x14 = (x14 << 16) | (x14 >> 16)
+		x9 += x14
+		x4 ^= x9
+		x4 = (x4 << 12) | (x4 >> 20)
+		x3 += x4
+		x14 ^= x3
+		x14 = (x14 << 8) | (x14 >> 24)
+		x9 += x14
+		x4 ^= x9
+		x4 = (x4 << 7) | (x4 >> 25)
+	}
+
+	x0 += j0
+	x1 += j1
+	x2 += j2
+	x3 += j3
+	x4 += j4
+	x5 += j5
+	x6 += j6
+	x7 += j7
+	x8 += j8
+	x9 += j9
+	x10 += j10
+	x11 += j11
+	x12 += j12
+	x13 += j13
+	x14 += j14
+	x15 += j15
+
+	binary.LittleEndian.PutUint32(out[0:4], x0)
+	binary.LittleEndian.PutUint32(out[4:8], x1)
+	binary.LittleEndian.PutUint32(out[8:12], x2)
+	binary.LittleEndian.PutUint32(out[12:16], x3)
+	binary.LittleEndian.PutUint32(out[16:20], x4)
+	binary.LittleEndian.PutUint32(out[20:24], x5)
+	binary.LittleEndian.PutUint32(out[24:28], x6)
+	binary.LittleEndian.PutUint32(out[28:32], x7)
+	binary.LittleEndian.PutUint32(out[32:36], x8)
+	binary.LittleEndian.PutUint32(out[36:40], x9)
+	binary.LittleEndian.PutUint32(out[40:44], x10)
+	binary.LittleEndian.PutUint32(out[44:48], x11)
+	binary.LittleEndian.PutUint32(out[48:52], x12)
+	binary.LittleEndian.PutUint32(out[52:56], x13)
+	binary.LittleEndian.PutUint32(out[56:60], x14)
+	binary.LittleEndian.PutUint32(out[60:64], x15)
+}
+
+// XORKeyStream crypts bytes from in to out using the given key and counters.
+// In and out must overlap entirely or not at all. Counter contains the raw
+// ChaCha20 counter bytes (i.e. block counter followed by nonce).
+func XORKeyStream(out, in []byte, counter *[16]byte, key *[32]byte) {
+	var block [64]byte
+	var counterCopy [16]byte
+	copy(counterCopy[:], counter[:])
+
+	for len(in) >= 64 {
+		core(&block, &counterCopy, key)
+		for i, x := range block {
+			out[i] = in[i] ^ x
+		}
+		u := uint32(1)
+		for i := 0; i < 4; i++ {
+			u += uint32(counterCopy[i])
+			counterCopy[i] = byte(u)
+			u >>= 8
+		}
+		in = in[64:]
+		out = out[64:]
+	}
+
+	if len(in) > 0 {
+		core(&block, &counterCopy, key)
+		for i, v := range in {
+			out[i] = v ^ block[i]
+		}
+	}
+}