csv-hasher.py

import argparse
import hashlib
import pandas as pd

def get_hash(input_str, algorithm, salt=""):
    hasher = hashlib.new(algorithm)
    hasher.update((salt + input_str).encode('utf-8'))
    return hasher.hexdigest()

def main(input_path, output_path, col_to_hash, algorithm, truncate_length, salt):
    df = pd.read_csv(input_path)

    if col_to_hash not in df.columns:
        print(f"Column '{col_to_hash}' not found.")
        return

    # Full hash
    df[f"{col_to_hash}_hash_full"] = df[col_to_hash].apply(lambda x: get_hash(str(x), algorithm, salt))

    # Optional truncation
    if truncate_length:
        df[f"{col_to_hash}_hash_truncated"] = df[f"{col_to_hash}_hash_full"].apply(lambda x: x[:truncate_length])

    df.to_csv(output_path, index=False)

    # Check for hash clashes if truncation is used
    if truncate_length:
        grouped = df.groupby(f"{col_to_hash}_hash_truncated").size().reset_index(name='counts')
        clashes = grouped[grouped['counts'] > 1]
        num_clashes = len(clashes)

        if num_clashes > 0:
            clash_percentage = (num_clashes / len(df)) * 100
            print(f"Warning: {num_clashes} hash clashes found ({clash_percentage:.2f}%).")
            
            clash_df = df[df[f"{col_to_hash}_hash_truncated"].isin(clashes[f"{col_to_hash}_hash_truncated"])]
            clash_log_path = f"{output_path.split('.')[0]}_log_clash.csv"
            clash_df.to_csv(clash_log_path, columns=[col_to_hash, f"{col_to_hash}_hash_full", f"{col_to_hash}_hash_truncated"], index=False)
            print(f"Clashes saved to {clash_log_path}.")
        else:
            print("No hash clashes found.")

if __name__ == "__main__":
    parser = argparse.ArgumentParser(description="Hash a specific column in a CSV file.")
    parser.add_argument("input_path", help="Path to the input CSV file.")
    parser.add_argument("output_path", help="Path to save the output CSV file.")
    parser.add_argument("col_to_hash", help="Name of the column to hash.")
    parser.add_argument("-a", "--algorithm", default="sha224", help="Hash algorithm to use. Default is 'sha224'.")
    parser.add_argument("-l", "--length", type=int, help="Length to truncate the hash. Optional.")
    parser.add_argument("-s", "--salt", default="", help="Optional salt for the hash.")
    args = parser.parse_args()

    main(args.input_path, args.output_path, args.col_to_hash, args.algorithm, args.length, args.salt)