Determining a cryptographic algorithm by description
It's RSA signature validation, using the PKCS-1.5 signature padding, with $e=3$, and the RSA modulus given by $\mathit{key}$.

It's a circa 1024 bit key; assuming $\mathit{key}$ is a properly chosen RSA modulus, nowadays it would be considered potentially breakable (in the sense that you could recover the private key, and hence be able to sign any message you want), however it would be a major effort.

If you're asking whether you can trust it, well, probably not; a well funded adversary could likely break it.  If you're asking whether you can break it, well, no; you're not a well funded adversary.