Although the legal system is slow to adapt to scientific advancements, Courtrooms can't stop the march of 'progress,' and slowly but surely, new modes of investigation and courtroom expertise find their way into the legal arena. Here are four you need to know about.

STEGANOGRAPHY

What is steganography, you ask? Well, look at the photo above, from the cable show Prison Break. Steganography is the art of hiding secret data within ordinary, non-secret files, like images, audio, or text. Here, the protagonist of Prison Break, Michael Scofield, has hidden the plans of the prison housing his brother within the lines of his body tattoo.

But Steganography is not just for TV shows and movies; it has real world applications. In U.S. v. Zheng, 113 F.4th 280 (2d Cir. 2024), the court affirmed the conviction of Xiaoqing Zheng for conspiring to commit economic sabotage. Using certain software Zheng encrypted 40 files related to the design and testing of carbon seals for GE's ground-based turbines. He then used steganography to embed those encrypted files into an image of a sunrise, so that when viewed normally, the files appeared to be no more than a picture of a sunrise but hid the encrypted files.

GEOFENCE WARRANTS

Next up, geofence warrants. Let's say police are investigating a robbery that occurred at a certain location on a particular day but have no clue who did it. Well, using a geofence warrant the police can subpoena Google for records of everyone that had location services activated on their phone that was within a certain radius of the robbery location during the relevant time period.

The U.S. Supreme Court has yet to rule on the Fourth Amendment implications of geofence warrants. However, several courts have addressed the issue, reflecting a circuit split between the Fourth Circuit and the Fifth Circuits. In a July 2024 opinion, the Fourth Circuit held that the use of geofence location history data warrant is not a search, and does not violate the Fourth Amendment. United States v. Chatrie, 107 F.4th 319 (4th Cir. 2024), affirmed en banc, 136 F.4th 100 (4th Cir. April 30, 2025) (en banc).

By contrast, in U.S. v. Smith, 110 F.4th 817 (5th Cir. 2024), the court held that obtaining geofence data from a geofence warrant constitutes a Fourth Amendment search; that defendants had a reasonable expectation of privacy in geofence location data from their cell phones that was protected by Fourth Amendment; and that the warrant failed to satisfy the probable cause and particularity requirements under the Fourth Amendment. However, the good faith exception to the exclusionary rule saved the evidence from suppression. U.S. v. Smith, 110 F.4th 817 (5th Cir. 2024).

VEHICLE FINGERPRINTS

What about a dragnet of cameras tracking everyone's license plates wherever they travel? In 2023, Norfolk, Va. officials installed 172 automatic license plate reader cameras (ALPRs) around the city, which (very nearly) track all of everyone’s travel by means of a “Vehicle Fingerprint” generated by the contractor that runs the system, Flock Safety, Inc. All footage is retained for 30 days, and during that time any Flock subscriber with access can log in and track any vehicle without a warrant, probable cause, or any judicial oversight. And because Flock pools its data in a centralized system, police can track drivers across the country, not just in any particular jurisdiction. Which raises some interesting Fourth Amendment issues, so last October the Institute for Justice teamed up with two Norfolk-area residents to challenge the dragnet in the Eastern District of Virginia, Norfolk Division.

Thus far, the court has denied defendants' motion to dismiss and so the litigation is ongoing. See Schmidt v. City of Norfolk, No. 2:24CV621, 2025 WL 410080 (E.D. Va. Feb. 5, 2025).

HASH VALUES

What is a hash value? A “hash” or “hash value” is “(usually) a short string of characters generated from a much larger string of data (say, an electronic image) using an algorithm—and calculated in a way that makes it highly unlikely another set of data will produce the same value.” United States v. Ackerman, 831 F.3d 1292, 1294 (10th Cir. 2016) (Gorsuch, J.).

In U.S. v. Maher, 120 F.4^th 297 (2d Cir. 2024) the Defendant had uploaded a digital file containing child pornography to his Google email account. Google reported to the National Center for Missing and Exploited Children (the “NCMEC”) its belief that the file contained “apparent child pornography.”

But they hadn’t actually opened and inspected the file. Rather, their report was based on a match between the hash value generated from someone else’s uploaded file — the so-called original image — which it had visually inspected and which contained child pornography, and a computer-conducted algorithmic search of the hash file of defendant Maher’s uploaded file.

Anyway, after learning of the hash value match law enforcement officers then physically viewed the contents of the defendant’s actual file without a warrant and confirmed it contained child pornography.

A search requiring a warrant? Or was no warrant needed because an identical private search had already been conducted, thus saving the search under the "private search doctrine"? The former, said the Second Circuit, since the private "search" was not a search of the actual file at all but rather a comparison of hash values. Nonetheless the good faith exception saved the search. Establishing a 2-2 split in the circuits.

CONCLUSION

These are just a few of the many scientific "advancements" that continue to find their way into the judicial system. Many more have already arrived, and others are just around the corner. We'll keep you posted.