Add frontend, backend and CLI

cli/packages/srp/util.go

@@ -0,0 +1,48 @@
+package srp
+
+import (
+	"encoding/hex"
+	"hash"
+	"math/big"
+	"regexp"
+)
+
+// Helpers
+
+func padTo(bytes []byte, length int) []byte {
+	paddingLength := length - len(bytes)
+	padding := make([]byte, paddingLength, paddingLength)
+
+	return append(padding, bytes...)
+}
+
+func padToN(number *big.Int, params *SRPParams) []byte {
+	return padTo(number.Bytes(), params.NLengthBits/8)
+}
+
+func hashToBytes(h hash.Hash) []byte {
+	return h.Sum(nil)
+}
+
+func hashToInt(h hash.Hash) *big.Int {
+	U := new(big.Int)
+	U.SetBytes(hashToBytes(h))
+	return U
+}
+
+func intFromBytes(bytes []byte) *big.Int {
+	i := new(big.Int)
+	i.SetBytes(bytes)
+	return i
+}
+
+func intToBytes(i *big.Int) []byte {
+	return i.Bytes()
+}
+
+func bytesFromHexString(s string) []byte {
+	re, _ := regexp.Compile("[^0-9a-fA-F]")
+	h := re.ReplaceAll([]byte(s), []byte(""))
+	b, _ := hex.DecodeString(string(h))
+	return b
+}