(Forbes) The threat quantum computers pose to the vaunted security of blockchain technology is profoundly real. Originally popular as fail-safe security for bitcoin enthusiasts, blockchain is making inroads across numerous industries, most notably as a track and trace tool proving the provenance of goods across vast supply chains. As blockchain services grow and quantum computers begin to emerge, now is the time to start thinking about quantum-resistant blockchain.
It’s difficult to go backwards on a blockchain’s immutable ledger and change original information in each block of the chain. This is especially the case as blocks are added with more data. People can’t easily rewrite history on its immutable ledger because other nodes on the chain would automatically reject any changes.
“Companies need to factor in the lifespan of their blockchains,” said Andrey Hoursanov, lead of quantum security at SAP. “If you’re using it to trace shipments from raw materials sourcing to delivery, maybe you’re looking at months, not years. In contrast, bitcoin investments typically take longer. That’s where you need to seriously consider how to protect the blockchain against quantum attacks likelier to happen further in the future.”
Anselme Tueno, researcher and cryptography expert at SAP Security Research, is on one of the teams at SAP exploring how to make software applications safe in a world with quantum computers.
“SAP is assessing post-quantum algorithms to determine how existing SAP applications can be made quantum-safe,” he said. “Replacing broken cryptography or integrating a new one takes decades. Moreover, the security of post-quantum algorithms is not fully understood, which is why we have to prepare to replace them if they are broken. This is called cryptographic agility.”

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