chore: import upstream snapshot with attribution

luaplugin/api_crypto.go

@@ -0,0 +1,40 @@
+package luaplugin
+
+import (
+	"crypto/hmac"
+	"crypto/md5"
+	"crypto/sha256"
+	"encoding/hex"
+
+	lua "github.com/yuin/gopher-lua"
+)
+
+// registerCryptoAPI adds cliamp.crypto.{md5,sha256,hmac_sha256} to the cliamp table.
+func registerCryptoAPI(L *lua.LState, cliamp *lua.LTable) {
+	tbl := L.NewTable()
+
+	L.SetField(tbl, "md5", L.NewFunction(func(L *lua.LState) int {
+		s := L.CheckString(1)
+		h := md5.Sum([]byte(s))
+		L.Push(lua.LString(hex.EncodeToString(h[:])))
+		return 1
+	}))
+
+	L.SetField(tbl, "sha256", L.NewFunction(func(L *lua.LState) int {
+		s := L.CheckString(1)
+		h := sha256.Sum256([]byte(s))
+		L.Push(lua.LString(hex.EncodeToString(h[:])))
+		return 1
+	}))
+
+	L.SetField(tbl, "hmac_sha256", L.NewFunction(func(L *lua.LState) int {
+		key := L.CheckString(1)
+		msg := L.CheckString(2)
+		mac := hmac.New(sha256.New, []byte(key))
+		mac.Write([]byte(msg))
+		L.Push(lua.LString(hex.EncodeToString(mac.Sum(nil))))
+		return 1
+	}))
+
+	L.SetField(cliamp, "crypto", tbl)
+}