I don't remember reading it was broken per say, just that there are some issues,...

ixwt on Sept 22, 2021 | parent | context | favorite | on: ‘Every message was copied to the police’

I don't remember reading it was broken per say, just that there are some issues, and weak keys. The only work I know of analyzing Solitare is [0]. And they propose some fixes to make it more resilient. OTP is by far the easiest and most reliable pencil and paper crypto algorithm though.

[0]: https://arxiv.org/abs/1909.06300