---
name: "skey"
section: "5"
platform: "openbsd"
package: "man"
version: "8.0-current-20261101"
release: "OpenBSD 8.0-current (2026-11-01)"
platforms: ["openbsd"]
url: "https://new.carta.tech/skey/5"
---

# skey(5)

one-time password user database

## NAME

**skey** – one-time password user database

## DESCRIPTION

The */etc/skey* directory contains user records for the S/Key one-time password authentication system.

Records take the form of files within */etc/skey*, where each file is named for the user whose record it contains. For example, */etc/skey/root* would hold root's S/Key record.

The mode for */etc/skey* should be 01730 and it should be owned by root and group auth. Individual records within */etc/skey* should be owned by the user they describe and be mode 0600. To access S/Key records, a process must run as group auth.

Each record consists of five lines:

1. The name of the user the record describes. This should be the same as the name of the file.

2. The hash type used for this entry: one of md5, sha1, or rmd160. The default is md5.

3. The sequence number. This is a decimal number between one and ten thousand. Each time the user authenticates via S/Key this number is decremented by one.

4. A seed used along with the sequence number and the six S/Key words to compute the value.

5. The value expected from the crunching of the user's seed, sequence number, and the six S/Key words. When the result matches this value, authentication is considered to have been successful.

## FILES

- */etc/skey*

  ## EXAMPLES

Here is a sample */etc/skey* file for root:

```
root
md5
99
obsd36521
1f4359a3764b675d
```

## SEE ALSO

[skey(1)](/skey/1.md), [skeyinit(1)](/skeyinit/1.md), skey(3)