Ok, I found the issue.
Actually it was 2 incompatibility back to back.
The crypto is encoding the base64 not URL safe, while ExPublicKey default option is to set it to true for decoding…
The second one was the wrong rsa padding by default
Node is using : RSA_PKCS1_OAEP_PADDING
while Erlang crypto uses rsa_pkcs1_padding
Setting Node to RSA_PKCS1_PADDING
everything worked finally…
