so go back to the vendor of the code, and ask for a vcs version.
To use with vcs, or any other tool really - the public key is provided by the tool vendor to whomever makes the IP, and have them encrypt with that key.
Please obtain IP_Decryptor v11 or IP_Decryptor_v13 and use it to decrypt the file.
If a decryption error occurs, it means the encrypted file was not encrypted correctly.
Since the file was improperly encrypted, it cannot be compiled.
Please share the compilation error log and ask the company or individual who provided the file to share it again properly.