text_index = encrypted_data.find(b'tEXt')
text_chunk = encrypted_data[text_index - 4:]
length = compat_struct_unpack('!I', text_chunk[:4])[0]
text_index = encrypted_data.find(b'tEXt')
text_chunk = encrypted_data[text_index - 4:]
length = compat_struct_unpack('!I', text_chunk[:4])[0]