Questions on Authentication of Video Evidence

Senator-Judge Alan Peter Cayetano sought clarification on how the NBI authenticated a video presented as evidence, particularly how its hash value was generated and used to establish the recording’s integrity. He pointed out that the NBI manually compared the screen-recorded video with the Facebook source, raising questions about how the court can independently determine that both recordings are the same video.
Transcript

PRESIDING SENATOR-JUDGE ESCUDERO:

(0:00:01) During the break, the presiding officer had a discussion with the senator judges, including Senator Cayetano. The presiding officer would therefore like to make of record the following. 

(0:00:16) Number one, should the defense, should the counsel for the respondent rather, decide as it has manifested to present the entire video, this court shall allow it during the time for the respondent to present its evidence in chief. We will not interfere with how each party or either party presents their case. With a caveat that a portion of an entire video being presented is not only to save on time, but also to be able to support the allegations from the point of view of the prosecution insofar as their articles of impeachment is concerned.

(0:00:58) Doubt, no need to say that the counsel for the respondent will also present the evidence that they deem best that will prove the innocence of the respondent in this case. Senator-Judge Cayetano. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:01:18) Sir Presiding Officer, I submit and I think there’s a consensus. May I ask just one question about authentication? 

PRESIDING SENATOR-JUDGE ESCUDERO:

(0:01:25) You may proceed, sir. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:01:27) With my indulgence to the prosecution and defense. Just to the witness, please correct me because I’m not really techy. So, you said, when you authenticate, you get the video and there’s a hash.

NBI SENIOR AGENT CALILUNG: 

(0:01:40) Yes, Your Honor. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:01:41) So, you get the hash, tapos you download the video. Tama po ba? 

NBI SENIOR AGENT CALILUNG:

(0:01:45) No, Your Honor. The video was screen recorded, Your Honor. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:01:49) Okay. So, screen recorded. Then, yung hash na nakuha mo. 

NBI SENIOR AGENT CALILUNG:

(0:01:54) Yung hash value po is cinalculate from the recorded po. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:01:55) Okay. Then, you have to compare that with the original one, right? 

NBI SENIOR AGENT CALILUNG:

(0:01:59) Yes, Your Honor. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:02:00) So, the original one, yung hash niyan, nasa Facebook. Tama ba?

NBI SENIOR AGENT CALILUNG:

(0:02:04) Yung hash po, hindi po cinalculate yung hash from the Facebook. Kasi ang purpose po ng hash value is to calculate yung value nung mismo video na nirecord ko. Dahil hindi po siya yung for authentication purpose, but for the integrity of the video that I screen recorded. If ma-tampered siya during the time na sinubmit siya until presented in court, makikita po na iba po yung hash value.

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:02:29) So is there a possibility that the hash of Facebook is different for the same video nung sa hash nung sa iyo? 

NBI SENIOR AGENT CALILUNG:

(0:02:35) Magkaiba po talaga yon.

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:02:37) Magkaiba. But how do you know it’s, when you authenticated, how do you know it’s the same video? 

NBI SENIOR AGENT CALILUNG:

(0:02:42) I manually compared, Your Honor. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:02:44) Manually compared? 

NBI SENIOR AGENT CALILUNG:

(0:02:45) Yes, Your Honor. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:02:46) So, but we don’t know that unless we also manually compare. 

NBI SENIOR AGENT CALILUNG:

(0:02:50) Yes, Your Honor. 

SENATOR-JUDGE ALAN PETER CAYETANO:

(0:02:51) Thank you. I just want to clarify that and think about it more.

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