crypto: Switch hkdfchacha back to xchacha (#2058)

hkdfchachapoly was a construction we came up with. There is no longer any
reason to use it. We should instead just use xchacha for the remaining use
cases we have. (Symmetrically encrypting the keys in the sdk keys package)

crypto/xchacha20poly1305/vector_test.go

@@ -0,0 +1,103 @@
+package xchacha20poly1305
+
+import (
+	"bytes"
+	"encoding/hex"
+	"testing"
+)
+
+func toHex(bits []byte) string {
+	return hex.EncodeToString(bits)
+}
+
+func fromHex(bits string) []byte {
+	b, err := hex.DecodeString(bits)
+	if err != nil {
+		panic(err)
+	}
+	return b
+}
+
+func TestHChaCha20(t *testing.T) {
+	for i, v := range hChaCha20Vectors {
+		var key [32]byte
+		var nonce [16]byte
+		copy(key[:], v.key)
+		copy(nonce[:], v.nonce)
+
+		HChaCha20(&key, &nonce, &key)
+		if !bytes.Equal(key[:], v.keystream) {
+			t.Errorf("Test %d: keystream mismatch:\n \t got:  %s\n \t want: %s", i, toHex(key[:]), toHex(v.keystream))
+		}
+	}
+}
+
+var hChaCha20Vectors = []struct {
+	key, nonce, keystream []byte
+}{
+	{
+		fromHex("0000000000000000000000000000000000000000000000000000000000000000"),
+		fromHex("000000000000000000000000000000000000000000000000"),
+		fromHex("1140704c328d1d5d0e30086cdf209dbd6a43b8f41518a11cc387b669b2ee6586"),
+	},
+	{
+		fromHex("8000000000000000000000000000000000000000000000000000000000000000"),
+		fromHex("000000000000000000000000000000000000000000000000"),
+		fromHex("7d266a7fd808cae4c02a0a70dcbfbcc250dae65ce3eae7fc210f54cc8f77df86"),
+	},
+	{
+		fromHex("0000000000000000000000000000000000000000000000000000000000000001"),
+		fromHex("000000000000000000000000000000000000000000000002"),
+		fromHex("e0c77ff931bb9163a5460c02ac281c2b53d792b1c43fea817e9ad275ae546963"),
+	},
+	{
+		fromHex("000102030405060708090a0b0c0d0e0f101112131415161718191a1b1c1d1e1f"),
+		fromHex("000102030405060708090a0b0c0d0e0f1011121314151617"),
+		fromHex("51e3ff45a895675c4b33b46c64f4a9ace110d34df6a2ceab486372bacbd3eff6"),
+	},
+	{
+		fromHex("24f11cce8a1b3d61e441561a696c1c1b7e173d084fd4812425435a8896a013dc"),
+		fromHex("d9660c5900ae19ddad28d6e06e45fe5e"),
+		fromHex("5966b3eec3bff1189f831f06afe4d4e3be97fa9235ec8c20d08acfbbb4e851e3"),
+	},
+}
+
+func TestVectors(t *testing.T) {
+	for i, v := range vectors {
+		if len(v.plaintext) == 0 {
+			v.plaintext = make([]byte, len(v.ciphertext))
+		}
+
+		var nonce [24]byte
+		copy(nonce[:], v.nonce)
+
+		aead, err := New(v.key)
+		if err != nil {
+			t.Error(err)
+		}
+
+		dst := aead.Seal(nil, nonce[:], v.plaintext, v.ad)
+		if !bytes.Equal(dst, v.ciphertext) {
+			t.Errorf("Test %d: ciphertext mismatch:\n \t got:  %s\n \t want: %s", i, toHex(dst), toHex(v.ciphertext))
+		}
+		open, err := aead.Open(nil, nonce[:], dst, v.ad)
+		if err != nil {
+			t.Error(err)
+		}
+		if !bytes.Equal(open, v.plaintext) {
+			t.Errorf("Test %d: plaintext mismatch:\n \t got:  %s\n \t want: %s", i, string(open), string(v.plaintext))
+		}
+	}
+}
+
+var vectors = []struct {
+	key, nonce, ad, plaintext, ciphertext []byte
+}{
+	{
+		[]byte{0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f, 0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b, 0x9c, 0x9d, 0x9e, 0x9f},
+		[]byte{0x07, 0x00, 0x00, 0x00, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4a, 0x4b},
+		[]byte{0x50, 0x51, 0x52, 0x53, 0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7},
+		[]byte("Ladies and Gentlemen of the class of '99: If I could offer you only one tip for the future, sunscreen would be it."),
+		[]byte{0x45, 0x3c, 0x06, 0x93, 0xa7, 0x40, 0x7f, 0x04, 0xff, 0x4c, 0x56, 0xae, 0xdb, 0x17, 0xa3, 0xc0, 0xa1, 0xaf, 0xff, 0x01, 0x17, 0x49, 0x30, 0xfc, 0x22, 0x28, 0x7c, 0x33, 0xdb, 0xcf, 0x0a, 0xc8, 0xb8, 0x9a, 0xd9, 0x29, 0x53, 0x0a, 0x1b, 0xb3, 0xab, 0x5e, 0x69, 0xf2, 0x4c, 0x7f, 0x60, 0x70, 0xc8, 0xf8, 0x40, 0xc9, 0xab, 0xb4, 0xf6, 0x9f, 0xbf, 0xc8, 0xa7, 0xff, 0x51, 0x26, 0xfa, 0xee, 0xbb, 0xb5, 0x58, 0x05, 0xee, 0x9c, 0x1c, 0xf2, 0xce, 0x5a, 0x57, 0x26, 0x32, 0x87, 0xae, 0xc5, 0x78, 0x0f, 0x04, 0xec, 0x32, 0x4c, 0x35, 0x14, 0x12, 0x2c, 0xfc, 0x32, 0x31, 0xfc, 0x1a, 0x8b, 0x71, 0x8a, 0x62, 0x86, 0x37, 0x30, 0xa2, 0x70, 0x2b, 0xb7, 0x63, 0x66, 0x11, 0x6b, 0xed, 0x09, 0xe0, 0xfd, 0x5c, 0x6d, 0x84, 0xb6, 0xb0, 0xc1, 0xab, 0xaf, 0x24, 0x9d, 0x5d, 0xd0, 0xf7, 0xf5, 0xa7, 0xea},
+	},
+}