Methodology · version 1.0
QDayWatch separates observations, estimates, scenarios, and editorial assessments. The distinction is the product.
There is insufficient public evidence to produce a scientifically defensible exact date. QDayWatch never turns a vendor roadmap, a qubit count, or a single research estimate into a countdown.
Logical error rates, code overhead, fault-tolerant operations, algorithmic improvements, cryptanalytic resource estimates, standards, deployments, and transition requirements. Each is useful on its own terms; none is silently converted into an arrival date.
X is how long vulnerable data must remain secret. Y is the time required to migrate. Z is a hypothetical time to a cryptographically relevant quantum computer.
The terms X and Y add because data may continue to be created throughout migration. Data protected on the final day before the transition completes can remain sensitive for another X years.
When X + Y exceeds Z, the modeled exposure window is open. Equality is shown as a zero-margin threshold—not as safety. Only X + Y below Z produces modeled migration margin. Z is always labeled as a scenario selected by the visitor.
A result performed under disclosed experimental conditions. It can be significant without being scalable, general-purpose, or cryptanalytically useful.
A model built from assumptions about algorithms, error rates, cycle times, connectivity, decoding, and architecture. We show dates and assumptions because estimates can change sharply without hardware changing at all.
A capability sufficient to attack a real production key at meaningful scale and reliability. A toy factoring demonstration is not classified as cryptographically relevant.
Architectures have different error rates, connectivity, gate sets, cycle times, and logical encodings. QDayWatch does not rank machines by raw physical-qubit count or combine incompatible vendor metrics into one chart.
When a number is shown, its architecture, observation date, source, and relevant uncertainty travel with it. Qualitative status indicators are explicitly labeled and are not a hidden composite score.