Unable to use key with RIPEMD160 hash

If a PGP key has RIPEMD160 as one of the allowed hashing algorithms, Keybase will not be able to use it, reporting:

```
error: public key corrupted: unknonw hash type: 1 (error #905)
```

Start by reproducing the failure with a PGP key that allows RIPEMD160 and confirm the reported unknown hash type error. Trace where the key's allowed hashing algorithms are parsed or checked, then verify that the key can be used without the corruption error. No source files or tests are identified in the issue, so locating the relevant entry point is part of the work.

Written by the indexing model from the issue text.