My question is about the original IBE proposal by Shamir from 1984: https://link.springer.com/content/pdf/10.1007/3-540-39568-7_5.pdf
In addition to proposing the idea of IBE, it also proposes a concrete Identity-based Signature scheme, however without proof of security or any reduction to a known assumption. Has it ever been proven to be secure since then, or otherwise, has an attack on it been suggested?
Thanks!
