2 Audio files (35MB each) to be certified as original and untempered

I am looking for a freelancer to certify two audio files for legal purposes. The entire files, which are in MP3 format and are 35MB each, need to be certified as original and untempered. At the end need to make an Affidavit for filing in an Australian court. I will provide with the Affidavit text, which needs to be signed/witnessed, which will be submitted to court.

Requirements:
- Experience in audio certification for legal purposes
- Australian certification for doing this type of work for legal purpose
- Proficiency in working with MP3 files
- Attention to detail to ensure the entire files are certified as original and untempered