| from llm_guard.input_scanners import PromptInjection | |
| from llm_guard.input_scanners.prompt_injection import MatchType | |
| def is_subsequence(main_string, sub_string): | |
| """ | |
| Checks if sub_string is a subsequence of main_string. | |
| A subsequence allows arbitrary characters in between the characters of sub_string in main_string. | |
| Parameters: | |
| main_string (str): The string in which to search. | |
| sub_string (str): The string to search for. | |
| Returns: | |
| bool: True if sub_string is a subsequence of main_string, False otherwise. | |
| """ | |
| main_string = main_string.lower() | |
| sub_string = sub_string.lower() | |
| main_len = len(main_string) | |
| sub_len = len(sub_string) | |
| if sub_len == 0: | |
| return True | |
| if main_len == 0: | |
| return False | |
| main_index = 0 | |
| sub_index = 0 | |
| while main_index < main_len and sub_index < sub_len: | |
| if main_string[main_index] == sub_string[sub_index]: | |
| sub_index += 1 | |
| main_index += 1 | |
| return sub_index == sub_len | |
| def is_malicious(user_input: str): | |
| """Function to check if the user input is malicious. Uses the LLM Guard prompt injection scanner. | |
| Uses a special model `ProtectAI/deberta-v3-base-prompt-injection-v2` to scan the user input for malicious content. | |
| """ | |
| scanner = PromptInjection(threshold=0.5, match_type=MatchType.FULL) | |
| sanitized_prompt, is_valid, risk_score = scanner.scan(user_input) | |
| return is_valid, risk_score | |