age(1) -- simple, modern, and secure file encryption
====================================================

## SYNOPSIS

`age` [`--encrypt`] (`-r` <RECIPIENT> | `-R` <PATH>)... [`--armor`] [`-o` <OUTPUT>] [<INPUT>]<br>
`age` [`--encrypt`] `--passphrase` [`--armor`] [`-o` <OUTPUT>] [<INPUT>]<br>
`age` `--decrypt` [`-i` <PATH>]... [`-o` <OUTPUT>] [<INPUT>]<br>

## DESCRIPTION

`age` encrypts or decrypts <INPUT> to <OUTPUT>. The <INPUT> argument is
optional and defaults to standard input. Only a single <INPUT> file may be
specified. If `-o` is not specified, <OUTPUT> defaults to standard output.

If `--passphrase` is specified, the file is encrypted with a passphrase
requested interactively. Otherwise, it's encrypted to one or more
[RECIPIENTS][RECIPIENTS AND IDENTITIES] specified with `-r`/`--recipient` or
`-R`/`--recipients-file`. Every recipient can decrypt the file.

In `--decrypt` mode, passphrase-encrypted files are detected automatically and
the passphrase is requested interactively. Otherwise, one or more
[IDENTITIES][RECIPIENTS AND IDENTITIES] specified with `-i`/`--identity` are
used to decrypt the file.

`age` encrypted files are binary and not malleable, with around 200 bytes of
overhead per recipient, plus 16 bytes every 64KiB of plaintext.

## OPTIONS

* `-o`, `--output`=<OUTPUT>:
    Write encrypted or decrypted file to <OUTPUT> instead of standard output.
    If <OUTPUT> already exists it will be overwritten.

    If encrypting without `--armor`, `age` will refuse to output binary to a
    TTY. This can be forced by specifying `-` as <OUTPUT>.

* `--version`:
    Print the version and exit.

### Encryption options

* `-e`, `--encrypt`:
    Encrypt <INPUT> to <OUTPUT>. This is the default.

* `-r`, `--recipient`=<RECIPIENT>:
    Encrypt to the explicitly specified <RECIPIENT>. See the
    [RECIPIENTS AND IDENTITIES][] section for possible recipient formats.

    This option can be repeated and combined with `-R`/`--recipients-file`,
    and the file can be decrypted by all provided recipients independently.

* `-R`, `--recipients-file`=<PATH>:
    Encrypt to the [RECIPIENTS][RECIPIENTS AND IDENTITIES] listed in the
    file at <PATH>, one per line. Empty lines and lines starting with `#`
    are ignored as comments.

    If <PATH> is `-`, the recipients are read from standard input. In
    this case, the <INPUT> argument must be specified.

    This option can be repeated and combined with `-r`/`--recipient`,
    and the file can be decrypted by all provided recipients independently.

* `-p`, `--passphrase`:
    Encrypt with a passphrase, requested interactively from the terminal.
    `age` will offer to auto-generate a secure passphrase.

    This options can't be used with `-r`/`--recipient` or
    `-R`/`--recipients-file`.

* `-a`, `--armor`:
    Encrypt to an ASCII-only "armored" encoding.
    
    `age` armor is a strict version of PEM with type `AGE ENCRYPTED FILE`,
    canonical "strict" Base64, no headers, and no support for leading and
    trailing extra data.

    Decryption transparently detects and decodes ASCII armoring.

### Decryption options

* `-d`, `--decrypt`:
    Decrypt <INPUT> to <OUTPUT>.

    If <INPUT> is passphrase encrypted, it will be automatically detected
    and the passphrase will be requested interactively. Otherwise, the
    [IDENTITIES][RECIPIENTS AND IDENTITIES] specified with `-i`/`--identity`
    are used.

    ASCII armoring is transparently detected and decoded.

* `-i`, `--identity`=<PATH>:
    Decrypt using the [IDENTITIES][RECIPIENTS AND IDENTITIES] at <PATH>.

    <PATH> may be one of the following:

    a\. A file listing [IDENTITIES][RECIPIENTS AND IDENTITIES] one per line.
    Empty lines and lines starting with "`#`" are ignored as comments.

    b\. A passphrase encrypted age file, containing
    [IDENTITIES][RECIPIENTS AND IDENTITIES] one per line like above.
    The passphrase is requested interactively. Note that passphrase-protected
    identity files are not necessary for most use cases, where access to the
    encrypted identity file implies access to the whole system.

    c\. An SSH private key file, in PKCS#1, PKCS#8, or OpenSSH format.
    If the private key is password-protected, the password is requested
    interactively only if the SSH identity matches the file. See the
    [SSH keys][] section for more information, including supported key types.
    
    d\. "`-`", causing one of the options above to be read from standard input.
    In this case, the <INPUT> argument must be specified.

    This option can be repeated. Identities are tried in the order in which
    are provided, and the first one matching one of the file's recipients is
    used. Unused identities are ignored.

    If `-e`/`--encrypt` is explicitly specified (to avoid confusion),
    `-i`/`--identity` may also be used to encrypt to the `RECIPIENTS`
    corresponding to the `IDENTITIES` listed at <PATH>. This allows using an
    identity file as a symmetric key, if desired.

## RECIPIENTS AND IDENTITIES

`RECIPIENTS` are public values, like a public key, that a file can be encrypted
to. `IDENTITIES` are private values, like a private key, that allow decrypting
a file encrypted to the corresponding `RECIPIENT`.

### Native X25519 keys

Native `age` key pairs are generated with age-keygen(1), and provide small
encodings and strong encryption based on X25519. They are the recommended
recipient type for most applications.

A `RECIPIENT` encoding begins with `age1` and looks like the following:

    age1gde3ncmahlqd9gg50tanl99r960llztrhfapnmx853s4tjum03uqfssgdh

An `IDENTITY` encoding begins with `AGE-SECRET-KEY-1` and looks like the
following:

    AGE-SECRET-KEY-1KTYK6RVLN5TAPE7VF6FQQSKZ9HWWCDSKUGXXNUQDWZ7XXT5YK5LSF3UTKQ

An encrypted file can't be linked to the native recipient it's encrypted to
without access to the corresponding identity.

### SSH keys

As a convenience feature, `age` also supports encrypting to RSA or Ed25519
ssh(1) keys. RSA keys must be at least 2048 bits. This feature employs more
complex cryptography, and should only be used when a native key is not available
for the recipient. Note that SSH keys might not be protected long-term by the
recipient, since they are revokable when used only for authentication.

A `RECIPIENT` encoding is an SSH public key in `authorized_keys` format
(see the `AUTHORIZED_KEYS FILE FORMAT` section of sshd(8)), starting with
`ssh-rsa` or `ssh-ed25519`, like the following:

    ssh-rsa AAAAB3NzaC1yc2EAAAADAQABAAABgQDULTit0KUehbi[...]GU4BtElAbzh8=
    ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIH9pO5pz22JZEas[...]l1uZc31FGYMXa

The comment at the end of the line, if present, is ignored.

In recipient files passed to `-R`/`--recipients-file`, unsupported but valid
SSH public keys are ignored with a warning, to facilitate using
`authorized_keys` or GitHub `.keys` files. (See [EXAMPLES][].)

An `IDENTITY` is an SSH private key _file_ passed individually to
`-i`/`--identity`. Note that keys held on hardware tokens such as YubiKeys
or accessed via ssh-agent(1) are not supported.

An encrypted file _can_ be linked to the SSH public key it was encrypted to.
This is so that `age` can identify the correct SSH private key before
requesting its password, if any.

## EXIT STATUS

`age` will exit 0 if and only if encryption or decryption are succesful for the
full length of the input.

If an error occurs during decryption, partial output might still be generated,
but only if it was possible to securely authenticate it. No unauthenticathed
output is ever released.

## BACKWARDS COMPATIBILITY

Files encrypted with a stable version (not alpha, beta, or release candidate) of
`age`, or with any v1.0.0 beta or release candidate, will decrypt with any later
version of the tool.

If decrypting older files poses a security risk, doing so might cause an error
by default, and a flag will be provided to force the operation.

## EXAMPLES

Generate a new identity, encrypt data, and decrypt:

    $ age-keygen -o key.txt
    Public key: age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p

    $ tar cvz ~/data | age -r age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p > data.tar.gz.age

    $ age -d -o data.tar.gz -i key.txt data.tar.gz.age

Encrypt `example.jpg` to multiple recipients and output to `example.jpg.age`:

    $ age -o example.jpg.age -r age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p \
        -r age1lggyhqrw2nlhcxprm67z43rta597azn8gknawjehu9d9dl0jq3yqqvfafg example.jpg

Encrypt to a list of recipients:

    $ cat > recipients.txt
    # Alice
    age1ql3z7hjy54pw3hyww5ayyfg7zqgvc7w3j2elw8zmrj2kg5sfn9aqmcac8p
    # Bob
    age1lggyhqrw2nlhcxprm67z43rta597azn8gknawjehu9d9dl0jq3yqqvfafg

    $ age -R recipients.txt example.jpg > example.jpg.age

Encrypt and decrypt a file using a passphrase:

    $ age -p secrets.txt > secrets.txt.age
    Enter passphrase (leave empty to autogenerate a secure one):
    Using the autogenerated passphrase "release-response-step-brand-wrap-ankle-pair-unusual-sword-train".

    $ age -d secrets.txt.age > secrets.txt
    Enter passphrase:

Encrypt and decrypt with a passphrase-protected identity file:

    $ age-keygen | age -p > key.age
    Public key: age1yhm4gctwfmrpz87tdslm550wrx6m79y9f2hdzt0lndjnehwj0ukqrjpyx5
    Enter passphrase (leave empty to autogenerate a secure one):
    Using the autogenerated passphrase "hip-roast-boring-snake-mention-east-wasp-honey-input-actress".

    $ age -r age1yhm4gctwfmrpz87tdslm550wrx6m79y9f2hdzt0lndjnehwj0ukqrjpyx5 secrets.txt > secrets.txt.age

    $ age -d -i key.age secrets.txt.age > secrets.txt
    Enter passphrase for identity file "key.age":

Encrypt and decrypt with an SSH public key:

    $ age -R ~/.ssh/id_ed25519.pub example.jpg > example.jpg.age

    $ age -d -i ~/.ssh/id_ed25519 example.jpg.age > example.jpg

Encrypt to the SSH keys of a GitHub user:

    $ curl https://github.com/benjojo.keys | age -R - example.jpg > example.jpg.age

## SEE ALSO

age-keygen(1)

## AUTHORS

Filippo Valsorda <age@filippo.io>
