DESILO FHE Library v1.9.0 Release Notes

DESILO FHE Library v1.9.0 is now available (released 2026-01-29). Highlights:

• A new parameter set now allows ciphertexts to retain up to 14 levels after bootstrap. Previously, the bootstrap operation could leave at most 10 levels. Lossy and sign bootstrap are not supported with this new parameter set. Please note that this is an experimental implementation, and ciphertexts and keys generated with it may not be compatible with future releases.
• Light Plaintext is newly introduced. This light version of the plaintext is much smaller in size, but has a limited expression range. The recommended range of values to encode is [-1, 1]. This data structure is not available for multiparty computation.
• Light Plain Matrix is newly introduced. This light version of the plain matrix is much smaller in size, but has a limited expression range. The recommended range of values to encode is [-1, 1]. This data structure is not available for multiparty computation.
• Sparse Plain Matrix is newly introduced. This sparse version of the plain matrix allows the users to encode sparse matrices, making the matrix multiplication operation faster and the memory size smaller. You can also create a Sparse Light Plain Matrix. For multiparty computation, you can create a Sparse Plain Matrix but not a Sparse Light Plain Matrix.
• Rotation of a ciphertext with bootstrap keys and lossy bootstrap keys are now supported.
• to_cpu and to_cuda APIs allow the user to manually move data structures in and out of the GPU.

Full release notes: https://fhe.desilo.dev/latest/release_notes/