Add Speck-128 implementation

cipher/speck/speck.go

@@ -0,0 +1,64 @@
+// Package speck implements (parts of) the Speck block cipher as defined in
+// https://eprint.iacr.org/2013/404.pdf.
+package speck
+
+import (
+	"fmt"
+
+	"git.omicron.one/playground/cryptography/cipher"
+	"git.omicron.one/playground/cryptography/cipher/speck/impl"
+)
+
+type SpeckParameters int
+
+const (
+	Speck3264 = iota + 1
+	Speck4872
+	Speck4896
+	Speck6496
+	Speck64128
+	Speck9696
+	Speck96144
+	Speck128128
+	Speck128192
+	Speck128256
+)
+
+var keySizes = []int{
+	0,  // unused
+	8,  // Speck3264
+	9,  // Speck4872
+	12, // Speck4896
+	12, // Speck6496
+	16, // Speck64128
+	12, // Speck9696
+	18, // Speck96144
+	16, // Speck128128
+	24, // Speck128192
+	32, // Speck128256
+}
+
+// New creates a new speck block cipher context.
+// Returns the created block cipher or an error.
+func New(key []byte, param SpeckParameters) (cipher.Block, error) {
+	if param == 0 || int(param) > len(keySizes) {
+		panic("Invalid parameters")
+	}
+	keySize := keySizes[param]
+	if len(key) != keySize {
+		return nil, cipher.ErrInvalidKeyLength
+	}
+	switch param {
+	case Speck3264:
+		return nil, fmt.Errorf("Not implemented")
+	case Speck4872, Speck4896:
+		return nil, fmt.Errorf("Not implemented")
+	case Speck6496, Speck64128:
+		return nil, fmt.Errorf("Not implemented")
+	case Speck9696, Speck96144:
+		return nil, fmt.Errorf("Not implemented")
+	case Speck128128, Speck128192, Speck128256:
+		return impl.New128(key)
+	}
+	panic("unreachable")
+}