The quantum threat to encryption: harvest now, decrypt later, post-quantum migration, and what an Indian business should do about data with a long shelf life.
The quantum threat to encryption is real but slow, and its practical form is harvest now, decrypt later: an adversary records encrypted traffic today and decrypts it when a quantum computer becomes capable. Public-key systems are the exposure, chiefly RSA and elliptic-curve schemes, while AES-256 and SHA-256 are not expected to fall to Shor's algorithm or Grover's search. For most Indian businesses the risk that matters is long-lived data: health records, contracts, government-issued identity documents and payment data that must stay confidential for a decade or more. The action is an inventory and a crypto-agility plan, not a panic migration.
It is an adversary storing encrypted traffic and logs now, with the intention of decrypting them once a cryptographically relevant quantum computer exists. The traffic is useless while it is encrypted, so there is no immediate signal that an attack has happened, which is what makes the pattern attractive to state and criminal actors alike. For an Indian business the question is not whether the data will be broken next year, but how long the data must remain confidential. A medical record, a signed contract, a government identity document and a payment trail all carry confidentiality requirements measured in years, and some in decades, which is long enough for the curve to bend. The data that can be thrown away after a year is not the problem; the archive is.
Two families, and the distinction matters. Public-key schemes, including RSA and elliptic-curve cryptography, are broken by Shor's algorithm, which solves the factorisation and discrete logarithm problems efficiently. That means a quantum computer of sufficient scale would break the key exchange and the signatures that TLS, code signing and document signing all depend on. Symmetric ciphers are not: AES-256 is not expected to be weakened by Grover's algorithm below an effective key size that is not practically reachable, and hash functions are similarly safe at 256 bits. So a quantum adversary is not an excuse to panic about your disk encryption, and it is a serious reason to plan a migration of your public-key layer, which in most estates means the certificate and key management estate rather than the data itself.
Three things, all of which take months rather than years. First, take a cryptographic inventory: find every place a key lives, including certificates, code signing keys, API keys, SSH keys, encryption libraries and their versions, plus the data each one protects and how long it must stay confidential. Second, buy crypto-agility, by ensuring that key lengths, algorithms and certificate authorities can be changed centrally rather than in deployed software. Third, start the long-life data migration, replacing RSA and ECC key exchange with post-quantum hybrid schemes for the systems that hold the archives, and re-encrypting the data itself. Doing these in order means a future migration is a configuration change rather than a rebuild, which is the entire difference between a three-month project and an eighteen-month one.
It adds a reason to have the inventory before the audit asks for it. The Digital Personal Data Protection Act, 2023 requires appropriate safeguards for personal data, DPDP Rule 7 notification obligations commence from May 2027, and 83% of Indian organisations have not begun comprehensive DPDP implementation. When a notification analysis requires you to show that a record was protected, the crypto inventory is the evidence, and if a cryptographic control is going to change, it is far better to change it before the archive is at rest in a scheme you will have to migrate later. The financial and health sectors in India will feel this first, because their retention horizons are the longest and their data the most sensitive.
| Primitive | Quantum-vulnerable? | Migration priority |
|---|---|---|
| RSA and ECC key exchange and signatures | Yes, via Shor's algorithm | High, for long-lived data |
| AES-128 | Weakened, not broken | Low, migrate to AES-256 |
| AES-256 | No practical weakness | None |
| SHA-256 | No practical weakness | None |
| Code and document signing keys | Yes, via Shor's algorithm | High, because rotation is slow |
The quantum threat to encryption is real but slow, and its practical form is harvest now, decrypt later: an adversary records encrypted traffic today and decrypts it when a quantum computer becomes capable. Public-key systems are the exposure, chiefly RSA and elliptic-curve schemes, while AES-256 and SHA-256 are not expected to fall to Shor's algorithm or Grover's search. For most Indian businesses the risk that matters is long-lived data: health records, contracts, government-issued identity documents and payment data that must stay confidential for a decade or more. The action is an inventory and a crypto-agility plan, not a panic migration.
Yes, if it is AES-256. Symmetric ciphers are not broken by Shor's algorithm, and Grover's search only halves the effective key size, which AES-256 absorbs. The part of your estate that needs attention is the public-key layer: TLS certificates, code signing keys, document signing and any RSA or ECC key exchange.
The practice of storing encrypted traffic and logs now, with the intent of decrypting them once a cryptographically relevant quantum computer exists. There is no immediate signal that it has happened, which is why long confidentiality requirements are what make the risk actionable rather than theoretical.
Crypto-agility is the ability to change algorithms, key lengths and key material centrally without rewriting deployed software. It is a cheaper and more durable investment than any single migration, because it makes the next one a configuration change rather than a rebuild.
It adds a reason to build the inventory early. DPDP Rule 7 notification obligations commence from May 2027, 83% of Indian organisations have not begun comprehensive DPDP implementation, and a notification analysis will require evidence of how a record was protected, including which scheme.
Yes. AAVETech runs a fixed-price cryptographic and key management review at roughly Rs 12,000 to Rs 30,000 per tester-day plus 18% GST, in 5 to 10 working days with a retest included, delivering an inventory, a crypto-agility gap list and a prioritised migration sequence.
Read the full guide on AAVETech: Should Indian Businesses Worry About Quantum Breaking Encryption?.
Send us your list of certificates, signing keys and encryption libraries and we will return a fixed-price crypto inventory and migration sequence.
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