feat: authsession service

authsession/internal/ports/code_hasher.go

@@ -0,0 +1,11 @@
+package ports
+
+// CodeHasher hashes cleartext confirmation codes and compares later user input
+// against stored hashes.
+type CodeHasher interface {
+	// Hash returns the stored representation for code.
+	Hash(code string) ([]byte, error)
+
+	// Compare reports whether hash matches code.
+	Compare(hash []byte, code string) (bool, error)
+}