Google Cloud announced quantum-safe key import for Cloud Key Management Service (Cloud KMS) on August 21, 2026. The capability is available in preview for software-based cryptographic keys and is designed to protect sensitive key material before a cryptographically relevant quantum computer emerges.
The announcement presents the feature as an updated quantum-safe bring-your-own-key capability and the first step in the next phase of Google Cloud’s post-quantum cryptography migration timeline. For organizations that manage their own software-based keys, the immediate change is a new import method within the existing Cloud KMS API workflow.
Addressing long-term exposure to encrypted data
Google Cloud is targeting the risk known as “store now, decrypt later.” An adversary could intercept and retain encrypted material today, then potentially try to decrypt it once a sufficiently capable quantum computer becomes available. Applying post-quantum protection during key import gives teams a way to address that long-term exposure as sensitive keys are brought into Cloud KMS.
Cloud KMS also provides post-quantum cryptography insights for monitoring an organization’s overall post-quantum posture. The two capabilities do not have the same availability status: the key-import mechanism remains in preview, while the monitoring insights are generally available.
How the Cloud KMS import flow works
The process starts when a client creates a Cloud KMS import job and requests a post-quantum HPKE import method. Cloud KMS then generates a post-quantum key-encapsulation mechanism (KEM) private key and exposes the corresponding public key to the client.
Using a supported cryptographic library such as Tink or OpenSSL, the client performs an HPKE Seal operation. This operation encapsulates the public key, derives an ephemeral AES key with HKDF-SHA256, and encrypts the target key material. The client submits the encapsulated ciphertext and encrypted material to the Cloud KMS endpoint, which Google Cloud says already has quantum-safe data-in-transit protection.
Cloud KMS performs an HPKE Open operation with the private portion of the wrapping key, decrypting the material within the Cloud KMS boundary. The supported KEM choices are X-Wing, ML-KEM-768, and ML-KEM-1024. Key derivation uses HKDF-SHA-256, while the symmetric wrapper uses AES-256-GCM with 12-byte nonces. The full flow is detailed in Google Cloud’s announcement.
What security teams can assess now
The preview gives teams that manage software-based keys a concrete path for evaluating quantum-safe import, but it does not reduce the broader transition to post-quantum cryptography to a single switch. Organizations still need to understand their existing cryptographic posture and determine which keys require protection against long-term interception risks.
The practical trade-off is clear. The import mechanism is available for evaluation now, but its preview status means each organization must assess its place in a production migration and governance process. The supported scope also remains centered on software-based cryptographic keys.
Google Cloud’s announcement therefore combines an immediate Cloud KMS capability with a longer migration effort. Customers can examine the preview import path and use the generally available insights to understand their broader post-quantum position, while treating the preview as one part of that transition rather than a complete migration.