I was able to figure out how to reproduce. I'm using 1Password for my SSH keys. If I export a key with a passphrase, and use that directly, I get the above error. However, if I reencrypt the same key by running `ssh-keygen -p -f id_textastic` using the same passphrase, it works! So there's something about the format of the private key from 1Password that's breaking things.

I created a brand new key for testing. Here it is as generated from 1Password, with passphrase `textastic`:

```

-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAAFmFlczI1Ni1nY21Ab3BlbnNzaC5jb20AAAAGYmNyeXB0AA
AAGAAAABDoOBmnaYBuneUKVSO4pTuqAAAAIAAAAAEAAAAzAAAAC3NzaC1lZDI1NTE5AAAA
IBVwMVbyFoRVzprJHiAdBrO+iR23mMtXATk8J7e0Ylq5AAAAkK5LV0a3LPS4RDp57J3oar
yg35gQ7zlTFEj1wLAK7+IuCMwCu/wFBIryPiLijliOAf8ekVDHdNqmHxaJEtW5pGJknZUV
W4uC8i2KSx8KPB+6hzsP1zHpy1lVOsXIk4457sfwdz/2w9JwDtMbDtXkeRsZNbMMa8U+Mf
sLKWfQjOHhO0ptiwNFCWi1Kfsx5lZO6WHuSgzlKg2RtMNHvpJhOAs=
-----END OPENSSH PRIVATE KEY-----

```

Public key:

```

ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIBVwMVbyFoRVzprJHiAdBrO+iR23mMtXATk8J7e0Ylq5

```

And then the same private key above, but after passing it through ssh-keygen first:

```

-----BEGIN OPENSSH PRIVATE KEY-----
b3BlbnNzaC1rZXktdjEAAAAACmFlczI1Ni1jdHIAAAAGYmNyeXB0AAAAGAAAABBDzuiiHD
xR9g013d2VjMucAAAAEAAAAAEAAAAzAAAAC3NzaC1lZDI1NTE5AAAAIBVwMVbyFoRVzprJ
HiAdBrO+iR23mMtXATk8J7e0Ylq5AAAAkCPgAzIc3G+jRAiZrTNrbCHpuI7XYOlPm8HRQU
H44NT5deLHvbGZTt95BPtDAcb39FJvgo9tNFQ+OdTrnp+PXrYvLw4HXeQ0k9V1NsqzOIsD
Mqj8oXZ5lUIq3XNSGmrqvziB9zMRgp+tZK0x0YLM82ZoLlP0q+++UCqYHIEgEZ9AVJL/L1
2YS6ToWmFtmNOFVQ==
-----END OPENSSH PRIVATE KEY-----

```

Yes, I did!

Aside, it would be good if the password wasn't specified if it was asked for interactively, matching the openssh CLI client.