South Korea’s National Tax Service (NTS) accidentally published a crypto wallet seed phrase in an official press release on Thursday, enabling thieves to take 4 million PRTG (Pre‑Retogeum) tokens — roughly $4.8 million — from the exposed address, local media reported.
The press release, covering the NTS’s enforcement campaign against tax delinquents and asset seizures, included an image of a Ledger cold wallet alongside a sheet of paper showing the wallet’s full mnemonic seed phrase with no blur or masking. Blockchain researchers traced an Ethereum address tied to the leaked phrase that briefly received the 4 million PRTG before the entire balance was moved out.
Onchain records show three inbound transfers totaling 4 million PRTG to that address, followed by a single outbound transfer sending exactly 4 million PRTG to another wallet, matching media accounts of the theft.
Associate professor Jaewoo Cho of Hansung University’s Blockchain Research Center, who analyzed the token flows, posted on X that “4 million PRTG tokens, worth approximately $4.8 million, were stolen from the mnemonic that was leaked (disclosed) through a press release from the National Tax Service.” He added that other exposed mnemonics the NTS published do not appear likely to cause major problems and suggested that because the stolen tokens are hard to cash out, the practical damage is limited. Cho said he hoped the incident would spur Korean public agencies to adopt proper virtual-asset custody systems.
The mistake comes amid broader scrutiny of Korean authorities’ crypto custody practices. In a separate case, police found in February 2026 that 22 Bitcoin seized in a 2021 hacking probe had gone missing from a cold wallet stored in a Gangnam police vault. Investigators arrested two suspects after determining the coins were moved using a mnemonic phrase the police never controlled.
Regulatory bodies are also under pressure following other high-profile errors, including a Bithumb incident that briefly credited users with about 620,000 BTC — roughly $43 billion in non-existent Bitcoin — and an extended Financial Services Commission probe after criticism it had not detected serious system flaws sooner.
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