new(project): Ciphey
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title = "Ciphey"
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title = "ciphey"
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weight = 1
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[taxonomies]
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tags = []
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+++
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Simply put, `ciphey` is a password and secret manager that is like
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[`pass`](https://passwordstore.org) if it used
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[`age`](https://age-encryption.org) instead of PGP. More than anything, it is
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an experiment to determine how cryptography can be combined in a minimalist
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manner to protect passwords in a way that accounts for the most realistic
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threats to their confidentiality, reliability, usability, and resiliency. It
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takes many of the database and key management ideas from
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[1Password](https://1password.com) and [Bitwarden](https://bitwarden.com) and
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combines them with the Unix-like philosophy of `pass`.
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To be clear, `ciphey` is still in development. [The remaining work is outlined
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below](#remaining-work). While I will be using it as my actual password manager,
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I strongly recommend that you only experiment with it and not rely on it for any
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actual passwords.
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*NOTE: This page is a work in progress.*
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## The Basics
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My goal is for `ciphey` to be simple enough that someone with a bit of knowledge
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about cryptography who wants to understand how their passwords are protected can
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do so after a short explanation. This sections aims to be that explanation.
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### Entries
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Everything you store in `ciphey` goes into an entry. Generally, you'll have one
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`entry` per password. However, passwords come in many different forms: as a
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result, entries are plaintext, which means any file can be used as an entry.
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This doesn't mean there is no structure to entries. For example, take a look at
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the entry for a hypothetical [`xkcd.com`](https://xkcd.com) account below:
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```
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correct horse battery staple
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name: xkcd.com
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tag: comics
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username: Tr0ub4dor&3
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url: https://xkcd.com/936
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To anyone who understands information theory and security and is in an
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infuriating argument with someone who does not (possibly involving mixed case),
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I sincerely apologize.
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```
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The first line of every entry is interpreted as the entry's "secret." In this
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case, the secret is `correct horse battery staple`, the password for the
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account. This is usually a password or private key, but can be any value that
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you might want to access by default. If this doesn't work for you for some
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reason, no worries; just leave the line blank.
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The secret is followed by any number of optional field-value pairs. Every
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field-value pair lives on its own line and can contain any information you want,
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so long as it follows the format `FIELD: VALUE`. Fields can be repeated and in
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any order. The only limitation is that your `FIELD` cannot contain a `: ` (`:`
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followed by a space), but the `VALUE` can.
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There are no `FIELD`s with any special meaning (yet), but keeping them
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consistent will help you find entries more quickly. I strongly recommend giving
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each entry a `name` field, as this is what `ciphey` uses to search for entries
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by default.
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Finally, the contents of the file from the first line that doesn't match the
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pattern `FIELD: VALUE` down to the end of the file is left uninterpreted,
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meaning that you can save any text that you'd like there. This is called the
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"note." In the example above, the "note" is the caption text from
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[xkcd.com/936](https://xkcd.com/936). Separate the notes and the preceding
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section with a newline.
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### The Entries
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Your `ciphey` database is a folder of files that can live on any filesystem.
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This folder is completely encrypted, and thus can safely be backed up, shared,
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or otherwise accessed without any unauthorized party gaining access to the
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contents of the file.
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```
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ciphey/
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└── entries/
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├── age1sdnql3ksstj7krh7azddygh860f6uttus5t3e9j52t4k5z34kutqyzgr4e.age
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├── age1ryutmsg486w4y06kq7w0rqm2s08r3sgzlwcl9p9p00jducedevvqkgrvyw.age
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├── age1mqr5htmadgzlmcdjks79d6ucfe5k46ruavnaxm08m64lpl6h5udqhkwwvp.age
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└── age1r908d20yj3ntp9q8g0448kwflfgf3au2qmhkkx7zp8xnesfdjfhqpd3r2d.age
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```
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Each file in the "entries" folder contains a single "entry." The name of each
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file is the `age` public key the entry is encrypted to. Every entry into your
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database is encrypted to a unique public key. Without that public key's
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corresponding private key, the contents of the entry cannot be accessed.
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However, keep in mind that some metadata does leak. Namely, any data associated
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with the filesystem (date created, date last modified, owner/group, etc.) is NOT
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protected by `ciphey` by default. It's still a good idea to keep your database
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away from any curious eyes when it's avoidable.
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### Your Keys
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Every time you unlock your `ciphey` database, you must have two things:
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1. Your `Primary Passphrase` (something you know)
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2. A `Device Key` (something you have)
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Every "device" you have (i.e. your desktop, laptop, and phone) has its own
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`Device Key`. This key is generated and stored as a normal file when you first
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set up `ciphey` on the device, and never leaves it.
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Each `Device Key` is encrypted with your `Primary Passphrase`. Without your
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`Primary Passphrase`, the `Device Key` cannot be used.
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Alternatively, you can use a `Device Key` stored on a hardware token, such as a
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Yubikey or OnlyKey. This has the added benefit that the key material never
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leaves the hardware token, protecting against attacks that can steal key
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material from your computer's local disk. In order to decrypt your entries, an
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attacker would have to physically have access your hardware token, in addition
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to learning your `Primary Passphrase`.
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### Entry Keys
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Every entry in your database is encrypted to a specific `Entry Key`. These entry
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keys are stored next to the `database` directory in the `keys` directory. Every
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entry gets its own key so that access can be cryptographically restricted on an
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entry-by-entry basis.
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The keys stored on the filesystem are encrypted to every `Device Key` that
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you've given access to the entry.
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### Disaster Recovery
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When you set up your `ciphey` database for the first time, you'll be prompted to
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create a `Recovery Key`, which is an `age` key encrypted with your `Recovery
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Passphrase` (By default, your `Primary Passphrase`, but this can optionally be
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changed). This key should be written down and stored in a safe place, such as in
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a safe. This way, if you lose all of your devices, you can still regain access
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to your passwords.
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You can also give a copy of this key and your `Recovery Passphrase` to anybody
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else who should have access to your accounts in case of an emergency. This way,
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you can be sure that you're unlikely to ever lose access to your `ciphey` keys.
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### Summary
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Every entry is encrypted with its own unique `Entry Key`.
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`Entry Key`s are encrypted to each `Device Key` that is granted access to the
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entry. They can be encrypted to other people's `Device Key`s to share an entry
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with them.
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`Device Key`s are encrypted with your `Primary Passphrase`. They can either live
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on your filesystem or on a hardware token, like a Yubikey.
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When you first set up `ciphey`, you also create a `Recovery Key`, which every
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`Entry Key` is encrypted to by default. This `Recovery Key` is encrypted with
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your `Recovery Passphrase`, which are to be stored offline in a safe place
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and/or given to trusted individuals so they can be used in case of an emergency.
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### Usage
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## Implementation
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### Entry Parsing
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The entry format was designed to be easy to parse for both humans and programs.
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The following Rust snippet is a (simplified) example of parsing an Entry from a
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String `s`:
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```rust
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// The entry's secret
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let mut secret: String;
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// A vector of key/value pairs
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let mut fields: (String, String) = Vec::new();
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// The entry's notes
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let mut notes: Option<String> = None;
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// An iterator over the decrypted lines of the entry file
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let mut lines = s.lines();
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// The first line contains the secret
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secret = lines.next();
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while let Some(line) = lines.by_ref().next() {
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if let Some((key, value)) = line.split_once(": ") {
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// Add the key and value to fields
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fields.push((key, value));
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} else {
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// Take the rest of the lines and put them into notes
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notes = Some(
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std::iter::once(line)
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.chain(lines.by_ref())
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.collect::<Vec<String>>()
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.join("\n"),
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);
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}
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}
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```
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This particular implementation has a lot of room for improvement. The biggest
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issue adding complexity is that Rust's `take_while` iterator method is
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consuming, not peekable, meaning that ownership of the lines it checks is passed
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to its closure. Thus, the following snippet, which is much easier to
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read, would not work:
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```rust
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// An iterator over the decrypted lines of the entry file
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let mut lines = s.lines();
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// The first line contains the secret
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secret = lines.next();
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// Take lines while they can be parsed as key/value pairs split by ": "
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fields = lines.take_while(line.split_once(": ")).map(...);
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// first line failing take_while is incorrectly dropped here
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// Join the remaining lines as notes
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notes = lines.collect::<Vec<String>>().join("\n");
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```
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This is because even though the first line that fails the conditional is
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consumed by `take_while`, it would neither be added to the fields (as it cannot
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be parsed as one) nor collected into the vector over the lines of notes, instead
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being dropped, causing data loss.
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There are a few Rust crates that provide a peekable `take_while`, but they're
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too big to justify as adding as dependencies for just this feature. It's
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possible that a simpler approach is possible using an iterative method, but I
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have not been able to come up with one yet.
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## Remaining Work
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### Password History
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At the moment, there is no built-in support for keeping track of entry changes
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over time. `pass` uses git to keep track of changes at the filesystem level,
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while password managers like Bitwarden have built-in support for storing the
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history of passwords over time.
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Currently, there is nothing stopping someone from manually checking entries into
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git or another backup solution. However, one way to provide better integration
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into `ciphey` would be to allow for `pre-hooks` and `post-hooks`. These hooks
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are scripts that are run before or after specific actions are taken by `ciphey`.
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This would allow, for example, automatically committing the changes to a git
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repository and pushing those changes to a remote server after every change made
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by `ciphey`.
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### File storage
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For the moment, entries must be plaintext files. If you want to encrypt an
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arbitrary file with `ciphey`, you have to manually create an encryption key,
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store that key as an entry in `ciphey`, and then manually encrypt said file with
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the newly-created key.
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It would be beneficial to devise a way to treat encrypted files just like any
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entry so that the key material for other files can be automatically managed in
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the same way.
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### Backup
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While `ciphey` makes sure that you don't lose your secret key material through
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the use of `Recovery Key`s, `ciphey` does not have any built-in backup system
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for the encrypted `ciphey` database. Of course, you can still back up `ciphey`
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like any other directory (which is a benefit of it living as just a plain
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directory), but it may be useful to consider ways that `ciphey` can better
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integrate or accomodate backups.
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