CloakPipe Vector — ADCPE distance-preserving vector encryption.
Encrypts embedding vectors using a secret orthogonal transformation so that approximate nearest-neighbor relationships are preserved. This means encrypted vectors can still be used for similarity search in vector databases, but cannot be inverted back to the original embeddings (which could leak the source text).
How it works
- A secret orthogonal matrix Q is derived from a key using Gram-Schmidt orthogonalization of a seeded random matrix.
- Each vector v is transformed: v' = Q * v (+ optional noise)
- Cosine similarity is preserved: cos(Qa, Qb) = cos(a, b)
- Optional Gaussian noise can be added for differential privacy, at the cost of slight distance distortion.