Where Does the Continuity of Original Hash Values Break in the Inter-Agency Transfer of Seized Electronic Information under the Amended Criminal Procedure Act in Force from October 2026?

Question

With the amendment of the Criminal Procedure Act (Act No. 22009) in force from 2 October 2026, the review of due process in the search and seizure of electronic information requires multi-stage verification far stricter than before. The central question is at what point procedural legitimacy is broken when the police or the Serious Crimes Investigation Agency refers or transfers to the Prosecution Service copies of electronic information extracted from storage media or cloud accounts, and a prosecutor of the Prosecution Service submits them to the court as evidence.

Unlike the former structure, in which an investigating prosecutor handed the record to a trial prosecutor within a single agency, in inter-agency transfer the continuity of hash values (integrity) among the original storage medium at the initial seizure site, the image files searched and selected, and the evidence files handed over to the Prosecution Service is separated, as is the identity of the body that delivers the list of seized items.

This brief applies the due-process requirements for search and seizure established by Supreme Court en banc decision 2011Mo1839, judgment 2018Do18866 and en banc judgment 2016Do348 to the multi-agency structure of criminal procedure in 2026, and sets out the points of procedural defect that the opposing party or the Prosecution Service may readily overlook and that can be used to challenge the evidence.

Material to check

First, the statement of the offence in the initial search and seizure warrant and the record prepared at the site of execution. It must be checked whether the storage medium itself was removed, whether selective seizure was attempted on site, and whether the reason for removal falls within the scope permitted by the warrant.

Second, the forensic imaging, search and copying logs of the investigative agency (the police or the Serious Crimes Investigation Agency) and the hash-value comparison tables. It is useful in practice to obtain and compare the hash value of the full image initially created, the hash values of the list of files created after selection for relevance to the suspected facts, and the confirmations of deletion or destruction of electronic information excluded from selection; however, the Criminal Procedure Act provisions and judgments cited do not make hash-value comparison or confirmations of deletion or destruction a requirement.

Third, the notices of the right of participation given to the person from whom the items were seized and to defence counsel, and the receipts for delivery of the list of seized items. It must be checked whether an opportunity to participate was guaranteed not only during the search at the investigative-agency stage but also at any later stage where further sorting or decryption took place after inter-agency referral or transfer.

Fourth, the record of stopping the search at the point when electronic information relating to a separate offence, unrelated to the suspected facts stated in the warrant, was discovered, and the history of the application for and issue of a separate search and seizure warrant.

Possible readings

The reading of the Public Prosecution Office is that, inasmuch as the initial investigative agency seized the electronic information under a lawful warrant, the subsequent transfer and referral to the Public Prosecution Office and the internal replication and inspection for preparation of submission at trial are merely acts of managing evidence already lawfully obtained, so no separate notice of right to participate or warrant is necessary.

By contrast, the reading of the right of defense (defense counsel) is that, in light of the legal principle of the Supreme Court en banc, the entire process of searching, replicating, and printing electronic information constitutes a single act of execution of search and seizure, and thus if extensive images or separate-case information that the investigative agency did not select passed to the Public Prosecution Office and were then re-searched, this is illegally obtained evidence that squarely circumvents the warrant requirement and the right to participate.

What the decisions held

Supreme Court en banc decision 2011Mo1839 rendered on 16 July 2015 held that, in the search and seizure of electronic information, the principle is to print out as documents, or copy as files, only the parts related to the suspected facts; that the right of participation of the person from whom the items were seized and of defence counsel must be guaranteed throughout the entire process of searching, copying and printing after the storage medium has been removed; and that electronic information relating to a separate offence discovered by chance in the course of a lawful search for electronic information related to the suspected facts may be lawfully searched and seized only where further searching is stopped and a search and seizure warrant for the separate suspected offence is obtained from the court.

Supreme Court judgment 2018Do18866 rendered on 1 June 2023 construed "relevance to the case concerned" under Article 215(1) of the Criminal Procedure Act as referring to cases in which an objective and personal nexus with the facts constituting the suspected offence as stated in the search and seizure warrant is recognised, and held that an investigative agency may not seize evidence unrelated to the suspected facts that formed the ground for issuing the warrant and, without a separate warrant, may not use such evidence as proof of guilt of an offence unrelated to those suspected facts.

Supreme Court en banc judgment 2016Do348 rendered on 18 November 2021 made clear that, even for an information storage medium voluntarily produced by a third party, the right of participation of the suspect who is in substance the person from whom the items were seized must be guaranteed unless there are special circumstances, and that relevance to the suspected facts that prompted the voluntary production must be interpreted even more restrictively; it thereby shut down the practice of investigative agencies using the form of voluntary production to circumvent the warrant requirement and the right of participation.

Practical checklist

First, whether the original hash value generated by the investigative agency and the hash value of the electronic files submitted as evidence by the Public Prosecution Office match without a single bit of discrepancy.

Second, whether the electronic information excluded from selection as unrelated to the suspected facts was deleted or disposed of when transferred from the investigative agency to the Public Prosecution Office, or whether the entire image was transferred as it was and re-searched at the Public Prosecution Office or in the course of supplementary investigation.

Third, whether, at each stage of search and selection, the date and place were notified in advance to the substantial person subject to seizure and defense counsel, and a detailed seizure inventory was served.

Fourth, whether there existed a section of unauthorized search and copying between the forensic work log at the point the separate-case information was discovered and the time of application for a separate warrant.

Glossary

Identity of the original (continuity of hash values): a practical method of verification by which it is confirmed, through comparison of hash function values and the like, that the electronic information stored on the storage medium at the time of seizure is identical to the copies or printouts submitted to the court. The Criminal Procedure Act provisions and judgments cited do not make this a legal requirement.

Relevance to the suspected facts (objective and personal nexus): a limiting principle under which an objective and personal nexus is recognised where the material is related to the suspected facts stated in the search and seizure warrant and has at least minimal value in proving them; it covers not only direct relevance but also indirect or circumstantial evidence for proving the motive for and background of the offence, the means and method of the offence, and the time and place of the offence, and personal nexus with the suspect or defendant may also be recognised in cases involving accomplices, indirect principals, necessary accomplices and the like.

Sources and limitations

This white paper was prepared on the basis of the Criminal Procedure Act confirmed at the National Law Information Center as of 2026-10-15 and Supreme Court en banc Decision 2011Mo1839, Supreme Court Decision 2018Do18866, and Supreme Court en banc Judgment 2016Do348.

This is general research material and is not legal advice on an individual criminal case.

Points left open

When a prosecutor of the Public Prosecution Office requests supplementary investigation and designates the scope of additional search of electronic information, how far the effect of the existing warrant extends and who becomes the person to give notice of the right to participate anew remain key practical issues.

When to reconsider

This white paper will be updated when the first judgment on the merits of the Supreme Court concerning inter-agency transfer of electronic information and supplementary investigation procedures under the criminal justice provisions taking effect in October 2026 is pronounced.

Statutes referred to

• 형사소송법 제106조, 제121조, 제122조, 제215조, 제219조, 제307조, 제308조의2
• 헌법 제12조 제1항·제3항

Decisions referred to

• 대법원 2015. 7. 16. 자 2011모1839 전원합의체 결정 · Decision ledger
• 대법원 2023. 6. 1. 선고 2018도18866 판결 · Decision ledger
• 대법원 2021. 11. 18. 선고 2016도348 전원합의체 판결 · Decision ledger

Verification status

The original texts of Articles 106, 121, 122, 215, 219, and 308-2 of the Criminal Procedure Act and the texts of Supreme Court en banc Decision 2011Mo1839, Supreme Court Decision 2018Do18866, and Supreme Court en banc Judgment 2016Do348 were cross-checked against the National Law Information Center as of 2026-10-15. The text of Supreme Court Decision 2018Do18866 was cross-checked again on 2026-10-21. This white paper cites only the judgments written in the decisions it addresses.