JLCPCB color silkscreen files are encrypted using AES-128-GCM and RSA-2048 with OAEP padding with SHA-256 as the hash function. Unfortunately, this means that, although it is possible for tools other than EasyEDA to create files, only JLCPCB can decrypt the resulting files.
The structure of an encrypted file is as follows:
- 256 bytes RSA-encrypted AES key
- 256 bytes RSA-encrypted GCM nonce