导读 对比两个文件相似度,python中可通过difflib.SequenceMatcher/ssdeep/python_mmdt/tlsh实现,
在大量需要对比,且文件较大时,需要更高的效率,可以考虑模糊哈希,本文就来和大家详细聊聊

对比两个文件相似度,python中可通过difflib.SequenceMatcher/ssdeep/python_mmdt/tlsh实现,在大量需要对比,且文件较大时,需要更高的效率,可以考虑模糊哈希(fuzzy hash),如ssdeep/python_mmdt

测试过程发现:

  • difflib方法,读取文件后,可以实现匹配度输出
  • ssdeep/mmdt/tlsh方法可以实现,实现提前模糊哈希值,验证时,只读取一次,完成对比,从而优化对比时间,及内存/cpu消耗
  • tlsh测试时,值越小,相似度越高,在对比小文件时,很不理想
  • 在对比小文件时,三种方法相差不大,在对比大文件(案例中81MB),difflib方法慢的难以接受
  • 在实际环境中,建议使用mmdt方法,因为ssdeep在二进制对比中差别较大,失去参考价值,具体还有哪些文件类型存在此问题有待考量,
  • 测试环境:

    OS:ubuntu20.04

    python:3.8.10

    py-tlsh==4.7.2

    python-mmdt==0.3.1

    ssdeep==3.4

    # -*- coding: utf-8 -*-
     
    import ssdeep
    import time
    from python_mmdt.mmdt.mmdt import MMDT
    from difflib import SequenceMatcher
     
    def difflib_test(file1,file2):
        start_time = time.time()
        with open(file1,'rb') as f:
            s1 = f.read()
        with open(file2,'rb') as f:
            s2 = f.read()
        match_obj =  SequenceMatcher(None,s1,s2)
        print("difflib match:",match_obj.ratio())
        end_time = time.time()
        print('difflib_test cost :',end_time-start_time)
     
    def mmdt_test(file1,file2):
        start_time = time.time()
        mmdt=MMDT()
        r1 = mmdt.mmdt_hash(file1)
        print(r1)
        r2 = mmdt.mmdt_hash_streaming(file2)
        print(r2)
        # sim1 = mmdt.mmdt_compare(file1, file2)
        # print("mmdt match:",sim1)
        sim2 = mmdt.mmdt_compare_hash(r1, r2)
        print("mmdt match:",sim2)
        end_time = time.time()
        print('mmdt_test cost :',end_time-start_time)
     
    def ssdeep_test(file1,file2):
        start_time = time.time()
        sig1=ssdeep.hash_from_file(file1)
        sig2=ssdeep.hash_from_file(file2)
        print(sig1)
        print(sig2)
        print("ssdeep match:",ssdeep.compare(sig1,sig2))
        end_time = time.time()
        print('ssdeep_test cost :',end_time-start_time)
     
    if __name__ == '__main__':
        start_time = time.time()
        file1='/root/test/fstab'
        file2='/root/test/fstab2'
        # file1 = '/root/test/initrd.img-5.4.0-125-generic'
        # file2 = '/root/test/initrd.img-5.4.0-135-generic'
        mmdt_test(file1,file2)    
        ssdeep_test(file1,file2)
        difflib_test(file1,file2)
        end_time = time.time()
        print('总执行时间:',end_time-start_time)

    下面给出对比小文件/大文件效果:

    测试tlsh

    import tlsh
    import time
     
    def tlsh_test(file1,file2):
        start_time = time.time()
        with open(file1,'rb') as f:
            s1 = tlsh.hash(f.read())
        with open(file2,'rb') as f:
            s2 = tlsh.hash(f.read())
        match_obj =  tlsh.diff(s1,s2)
        print("tlsh match:",match_obj)
        end_time = time.time()
        print('difflib_test cost :',end_time-start_time)
     
     
    if __name__ == '__main__':
        start_time = time.time()
        # file1='/root/test/fstab'
        # file2='/root/test/fstab2'
        file1 = '/root/test/initrd.img-5.4.0-125-generic'
        file2 = '/root/test/initrd.img-5.4.0-135-generic'
        tlsh_test(file1,file2)
        end_time = time.time()
        print('总执行时间:',end_time-start_time)

    对比小文件/大文件

    到此这篇关于Python利用模糊哈希实现对比文件相似度的文章就介绍到这了

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