Offline verification method for validity period of license

The invention relates to the field of license verification, and relates to an offline verification method for the validity period of a license. The method comprises the steps that S1, acquiring a license file generated by a license server and judging whether the license file passes verification by local equipment; S2, running the license file, generating a running duration file according to the accumulated running duration of the license, and performing self-checking encryption on the running duration file to generate an encrypted running duration file; S3, judging whether the running durationof the license file exceeds the permission duration of the license file according to the running duration file; and S4, judging whether the system time of the local equipment exceeds the permission time of the license according to the running duration file. The technical scheme has the beneficial effects that the running time length file is generated through self-checking encryption, so that therunning time length file h