fix issue

4 files changed, 212 insertions, 0 deletions

diff --git a/ec_test.go b/ec_test.go
new file mode 100644
index 0000000..b0874c6
--- /dev/null
+++ b/ec_test.go
@@ -0,0 +1,64 @@
+package ecookie
+
+import (
+	"encoding/json"
+	"testing"
+)
+
+type test struct {
+	Foo string
+	Bar string
+}
+
+const pattr string = "ecookie: --- %v --"
+
+const (
+	foo = "foo string"
+	bar = "bar string"
+)
+
+var key = []byte{
+	0x11, 0x12, 0x13, 0x14,
+	0x11, 0x12, 0x13, 0x14,
+	0x11, 0x12, 0x13, 0x14,
+	0x11, 0x12, 0x13, 0x14,
+}
+
+func TestEcookie(t *testing.T) {
+	enc, err := NewEncryptor(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	tx := &test{Foo: foo, Bar: bar}
+	bx := new(test)
+	bt, err := json.Marshal(tx)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	ct, err := enc.Encrypt(bt)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	t.Logf(pattr, string(ct))
+
+	dec, err := NewDecryptor(key)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	pt, err := dec.Decrypt(ct)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if err := json.Unmarshal(pt, bx); err != nil {
+		t.Fatal(err)
+	}
+
+	if !(*tx == *bx) {
+		t.Error("error: tx != bx.. test failed")
+	}
+}
diff --git a/ecookie.go b/ecookie.go
new file mode 100644
index 0000000..767091e
--- /dev/null
+++ b/ecookie.go
@@ -0,0 +1,126 @@
+package ecookie
+
+import (
+	"bytes"
+	"crypto/rand"
+	"encoding/hex"
+	"errors"
+	"io"
+
+	"golang.org/x/crypto/blake2b"
+	"snix.ir/rabbitio"
+)
+
+var (
+	ErrAUTHCOK = errors.New("ecookie: cookie is corrupted")
+	ErrENDDATA = errors.New("ecookie: cookie length is too short")
+	ErrNotVlid = errors.New("ecookie: data is not validated")
+
+	ErrBadKlen = errors.New("ecookie: key must be 16 byte len")
+)
+
+const (
+	lenhashfnc = 32
+	lenkrabbit = 16
+	lenivahash = lenhashfnc + lenivforkt
+	lenivforkt = 8
+)
+
+type Encryptor struct {
+	key []byte
+}
+
+type Decryptor struct {
+	key []byte
+}
+
+func NewEncryptor(key []byte) (*Encryptor, error) {
+	if len(key) != lenkrabbit {
+		return nil, ErrBadKlen
+	}
+	copyKey := make([]byte, lenkrabbit)
+	copy(copyKey, key)
+	return &Encryptor{key: copyKey}, nil
+}
+
+func NewDecryptor(key []byte) (*Decryptor, error) {
+	if len(key) != lenkrabbit {
+		return nil, ErrBadKlen
+	}
+	copyKey := make([]byte, lenkrabbit)
+	copy(copyKey, key)
+	return &Decryptor{key: copyKey}, nil
+}
+
+func randomIVGen() ([]byte, error) {
+	iv := make([]byte, lenivforkt)
+	if _, err := rand.Read(iv); err != nil {
+		return nil, err
+	}
+	return iv, nil
+}
+
+func (h *Encryptor) Encrypt(src []byte) ([]byte, error) {
+	ivx, err := randomIVGen()
+	if err != nil {
+		return nil, err
+	}
+
+	cip, _ := rabbitio.NewCipher(h.key, ivx)
+	dst := make([]byte, len(src))
+	cip.XORKeyStream(dst, src)
+	hash, err := blake2bHash(multiReader(h.key, ivx, dst))
+	if err != nil {
+		return nil, err
+	}
+
+	buff := new(bytes.Buffer)
+	_, err = io.Copy(hex.NewEncoder(buff), multiReader(hash, ivx, dst))
+	return buff.Bytes(), err
+}
+
+func multiReader(vs ...[]byte) io.Reader {
+
+	var rds []io.Reader
+	for _, x := range vs {
+		r := bytes.NewReader(x)
+		rds = append(rds, r)
+	}
+
+	return io.MultiReader(rds...)
+}
+
+func blake2bHash(r io.Reader) ([]byte, error) {
+	hasher, _ := blake2b.New256(nil)
+	if _, err := io.Copy(hasher, r); err != nil {
+		return nil, err
+	}
+	return hasher.Sum(nil), nil
+}
+
+func (h *Decryptor) Decrypt(raw []byte) ([]byte, error) {
+	bf := new(bytes.Buffer)
+	if _, err := io.Copy(bf,
+		hex.NewDecoder(bytes.NewReader(raw))); err != nil {
+		return nil, err
+	}
+
+	if bf.Len() < lenivahash {
+		return nil, ErrENDDATA
+	}
+
+	u := bf.Bytes()
+	cl, err := blake2bHash(multiReader(h.key, u[lenhashfnc:]))
+	if err != nil {
+		return nil, err
+	}
+
+	if !bytes.Equal(cl, u[:lenhashfnc]) {
+		return nil, ErrAUTHCOK
+	}
+
+	cip, _ := rabbitio.NewCipher(h.key, u[lenhashfnc:lenivahash])
+	pln := make([]byte, bf.Len()-lenivahash)
+	cip.XORKeyStream(pln, u[lenivahash:])
+	return pln, err
+}
diff --git a/go.mod b/go.mod
new file mode 100644
index 0000000..610e44a
--- /dev/null
+++ b/go.mod
@@ -0,0 +1,10 @@
+module snix.ir/ecookie
+
+go 1.17
+
+require (
+	golang.org/x/crypto v0.0.0-20220131195533-30dcbda58838
+	snix.ir/rabbitio v0.0.0-20220123060014-f8c9838efbd6
+)
+
+require golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 // indirect
diff --git a/go.sum b/go.sum
new file mode 100644
index 0000000..16e9b2b
--- /dev/null
+++ b/go.sum
@@ -0,0 +1,12 @@
+golang.org/x/crypto v0.0.0-20220131195533-30dcbda58838 h1:71vQrMauZZhcTVK6KdYM+rklehEEwb3E+ZhaE5jrPrE=
+golang.org/x/crypto v0.0.0-20220131195533-30dcbda58838/go.mod h1:IxCIyHEi3zRg3s0A5j5BB6A9Jmi73HwBIUl50j+osU4=
+golang.org/x/net v0.0.0-20211112202133-69e39bad7dc2/go.mod h1:9nx3DQGgdP8bBQD5qxJ1jj9UTztislL4KSBs9R2vV5Y=
+golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210423082822-04245dca01da/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1 h1:SrN+KX8Art/Sf4HNj6Zcz06G7VEz+7w9tdXTPOZ7+l4=
+golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
+golang.org/x/text v0.3.6/go.mod h1:5Zoc/QRtKVWzQhOtBMvqHzDpF6irO9z98xDceosuGiQ=
+golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGmLbDWY5pfWTLqBcC2KZ6jyYvM4mQ=
+snix.ir/rabbitio v0.0.0-20220123060014-f8c9838efbd6 h1:LYGzvcaDnb0d6ZGWpG3j0qJjEIseRJaFwLN8gbIZ+Io=
+snix.ir/rabbitio v0.0.0-20220123060014-f8c9838efbd6/go.mod h1:fGdJrOtVK0uqEI8x6SBI/NPAAQmtQi/4sjwQPShasEA=