Feat/block api iv

lib/rex/text/block_api.rb

@@ -11,22 +11,25 @@ module Text
     #
     # @param mod [String] The name of the module containing the target function.
     # @param fun [String] The name of the function.
+    # @param iv [Integer] The 32-bit initialization vector (IV) to use for the hash operation
     #
     # @return [String] The hash of the mod/fun pair in string format
-    def self.block_api_hash(mod, func)
-      unicode_mod = (mod.upcase + "\x00").unpack('C*').pack('v*')
-      mod_hash = self.ror13_hash(unicode_mod)
-      fun_hash = self.ror13_hash(func + "\x00")
-      "0x#{(mod_hash + fun_hash & 0xFFFFFFFF).to_s(16)}"
+    def self.block_api_hash(mod, func, iv: 0)
+      unicode_mod = (mod.upcase).unpack('C*').pack('v*')
+      mod_hash = self.ror13_hash(unicode_mod, iv: iv)
+      fun_hash = self.ror13_hash(func + "\x00", iv: mod_hash)
+      "0x#{(fun_hash & 0xFFFFFFFF).to_s(16)}"
     end
 
     #
     # Calculate the ROR13 hash of a given string
+    # @param string [String] The string to hash
+    # @param iv [Integer] The 32-bit initialization vector (IV) to use for the hash operation
     #
     # @return [Integer]
-    def self.ror13_hash(name)
-      hash = 0
-      name.unpack("C*").each {|c| hash = ror(hash, 13); hash += c }
+    def self.ror13_hash(string, iv: 0)
+      hash = (iv & 0xFFFFFFFF)
+      string.unpack("C*").each {|c| hash = ror(hash, 13); hash += c }
       hash
     end
   end