superpower `keyfork mnemonic generate`

crates/keyfork/src/clap_ext.rs

@@ -0,0 +1,60 @@
+//! Extensions to clap.
+
+use std::{collections::HashMap, str::FromStr};
+
+/// A helper struct for clap arguments that can contain additional arguments. For example:
+/// `keyfork mnemonic generate --encrypt-to cert.asc,output=encrypted.asc`.
+#[derive(Clone, Debug)]
+pub struct ValueWithOptions<T: FromStr>
+where
+    T::Err: std::error::Error,
+{
+    /// A mapping between keys and values.
+    pub values: HashMap<String, String>,
+
+    /// The first variable for the argument, such as a [`PathBuf`].
+    pub inner: T,
+}
+
+/// An error that occurred while parsing a base value or its
+#[derive(Debug, thiserror::Error)]
+pub enum ValueParseError {
+    /// No value was given; the required type could not be parsed.
+    #[error("No value was given")]
+    NoValue,
+
+    /// The first value could not properly be parsed.
+    #[error("Could not parse first value: {0}")]
+    BadParse(String),
+
+    /// Additional values were added, but not in a key=value format.
+    #[error("A key-value pair was not given")]
+    BadKeyValue,
+}
+
+impl<T: std::str::FromStr> FromStr for ValueWithOptions<T>
+where
+    <T as FromStr>::Err: std::error::Error,
+{
+    type Err = ValueParseError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        let mut values = s.split(',');
+        let first = values.next().ok_or(ValueParseError::NoValue)?;
+        let mut others = HashMap::new();
+        for value in values {
+            let [lhs, rhs] = value
+                .splitn(2, '=')
+                .collect::<Vec<_>>()
+                .try_into()
+                .map_err(|_| ValueParseError::BadKeyValue)?;
+            others.insert(lhs.to_string(), rhs.to_string());
+        }
+        Ok(Self {
+            inner: first
+                .parse()
+                .map_err(|e: <T as FromStr>::Err| ValueParseError::BadParse(e.to_string()))?,
+            values: others,
+        })
+    }
+}

crates/keyfork/src/cli/mnemonic.rs

@@ -1,6 +1,34 @@
+use super::provision;
 use super::Keyfork;
+use crate::{clap_ext::*, config};
 use clap::{builder::PossibleValue, Parser, Subcommand, ValueEnum};
-use std::fmt::Display;
+use std::{
+    collections::HashMap,
+    fmt::Display,
+    fs::File,
+    io::Write,
+    path::{Path, PathBuf},
+    str::FromStr,
+};
+
+use keyfork_derive_openpgp::{
+    openpgp::{
+        self,
+        armor::{Kind, Writer},
+        packet::UserID,
+        policy::StandardPolicy,
+        serialize::{
+            stream::{Encryptor2, LiteralWriter, Message, Recipient},
+            Serialize,
+        },
+        types::KeyFlags,
+    },
+    XPrv,
+};
+use keyfork_prompt::default_handler;
+use keyfork_shard::{openpgp::OpenPGP, Format};
+
+type StringMap = HashMap<String, String>;
 
 #[derive(Clone, Debug, Default)]
 pub enum SeedSize {
@@ -96,21 +124,22 @@ impl std::str::FromStr for MnemonicSeedSource {
 }
 
 impl MnemonicSeedSource {
-    pub fn handle(&self, size: &SeedSize) -> Result<String, Box<dyn std::error::Error>> {
+    pub fn handle(
+        &self,
+        size: &SeedSize,
+    ) -> Result<keyfork_mnemonic::Mnemonic, Box<dyn std::error::Error>> {
         let size = match size {
             SeedSize::Bits128 => 128,
             SeedSize::Bits256 => 256,
         };
         let seed = match self {
-            MnemonicSeedSource::System => {
-                keyfork_entropy::generate_entropy_of_size(size / 8)?
-            }
+            MnemonicSeedSource::System => keyfork_entropy::generate_entropy_of_size(size / 8)?,
             MnemonicSeedSource::Playing => todo!(),
             MnemonicSeedSource::Tarot => todo!(),
             MnemonicSeedSource::Dice => todo!(),
         };
         let mnemonic = keyfork_mnemonic::Mnemonic::try_from_slice(&seed)?;
-        Ok(mnemonic.to_string())
+        Ok(mnemonic)
     }
 }
 
@@ -124,6 +153,10 @@ pub enum MnemonicSubcommands {
     /// method of generating a seed using system entropy, as well as various forms of loading
     /// physicalized entropy into a mnemonic. The mnemonic should be stored in a safe location
     /// (such as a Trezor "recovery seed card") and never persisted digitally.
+    ///
+    /// When using the `--shard`, `--shard-to`, `--encrypt-to`, and `--encrypt-to-self` +
+    /// `--provision` arguments, the mnemonic is _not_ sent to output. The data for the mnemonic is
+    /// then either split using Keyfork Shard or encrypted using OpenPGP.
     Generate {
         /// The source from where a seed is created.
         #[arg(long, value_enum, default_value_t = Default::default())]
@@ -132,17 +165,423 @@ pub enum MnemonicSubcommands {
         /// The size of the mnemonic, in bits.
         #[arg(long, default_value_t = Default::default())]
         size: SeedSize,
+
+        /// Encrypt the mnemonic to an OpenPGP certificate in the provided path.
+        ///
+        /// When given arguments in the format `--encrypt-to input.asc,output=output.asc`, the
+        /// output of the encryption will be written to `output.asc`. Otherwise, the default
+        /// behavior is to write the output to `input.enc.asc`. If the output file already exists,
+        /// it will not be overwritten, and the command will exit unsuccessfully.
+        #[arg(long)]
+        encrypt_to: Option<Vec<ValueWithOptions<PathBuf>>>,
+
+        /// Shard the mnemonic to the certificates in the given Shardfile. Requires a decrypt
+        /// operation on the Shardfile to access the metadata and certificates.
+        ///
+        /// When given arguments in the format `--encrypt-to input.asc,output=output.asc`, the
+        /// output of the encryption will be written to `output.asc`. Otherwise, the default
+        /// behavior is to write the output to `input.new.asc`. If the output file already exists,
+        /// it will not be overwritten, and the command will exit unsuccessfully.
+        #[arg(long)]
+        shard_to: Option<Vec<ValueWithOptions<PathBuf>>>,
+
+        /// Shard the mnemonic to the provided certificates.
+        ///
+        /// The following additional arguments are available:
+        ///
+        /// * threshold, m: the minimum amount of shares required to reconstitute the shard. By
+        ///   default, this is the amount of certificates provided.
+        ///
+        /// * max, n: the maximum amount of shares. When provided, this is used to ensure the
+        ///   certificate count is correct. This is required when using `threshold` or `m`.
+        ///
+        /// * output: the file to write the generated Shardfile to. By default, assuming the
+        ///   certificate input is `input.asc`, the generated Shardfile would be written to
+        ///   `input.shard.asc`.
+        #[arg(long)]
+        shard: Option<Vec<ValueWithOptions<PathBuf>>>,
+
+        /// Encrypt the mnemonic to an OpenPGP certificate derived from the mnemonic, writing the
+        /// output to the provided path. This command must be run in combination with
+        /// `--provision openpgp-card` or another relevant provisioner, to ensure the newly
+        /// generated mnemonic would be decryptable by some form of provisioned hardware.
+        ///
+        /// When given arguments in the format `--encrypt-to-self output.asc,output=encrypted.asc`,
+        /// the output of the OpenPGP certificate will be written to `output.asc`, while the output
+        /// of the encryption will be written to `encrypted.asc`. Otherwise, the
+        /// default behavior is to write the encrypted mnemonic to `output.enc.asc`. If either
+        /// output file already exists, it will not be overwritten, and the command will exit
+        /// unsuccessfully.
+        ///
+        /// Additionally, when given the `account=` option (which must match the `account=` option
+        /// of the relevant provisioner), the given account will be used instead of the default
+        /// account of 0.
+        ///
+        /// Because a new OpenPGP key needs to be created, a User ID can also be supplied, using
+        /// the option `userid=<your User ID>`. It can contain any characters that are not a comma.
+        #[arg(long)]
+        encrypt_to_self: Option<ValueWithOptions<PathBuf>>,
+
+        /// Provision a key derived from the mnemonic to a piece of hardware such as an OpenPGP
+        /// smartcard. This argument is required when used with `--encrypt-to-self`.
+        ///
+        /// Additional arguments, such as the amount of hardware to provision and the
+        /// account to use when deriving, can be specified by using (for example)
+        /// `--provision openpgp-card,count=2,account=1`.
+        #[arg(long)]
+        provision: Option<ValueWithOptions<provision::Provisioner>>,
     },
 }
 
+// NOTE: This function defaults to `.asc` in the event no extension is found.
+// This is specific to OpenPGP. If you want to use this function elsewhere (why?),
+// be sure to use a relevant extension for your context.
+fn determine_valid_output_path<T: AsRef<Path>>(
+    path: &Path,
+    mid_ext: &str,
+    optional_path: Option<T>,
+) -> PathBuf {
+    match optional_path {
+        Some(p) => p.as_ref().to_path_buf(),
+        None => {
+            let extension = match path.extension() {
+                Some(ext) => format!("{mid_ext}.{ext}", ext = ext.to_string_lossy()),
+                None => format!("{mid_ext}.asc"),
+            };
+            path.with_extension(extension)
+        }
+    }
+}
+
+fn is_extension_armored(path: &Path) -> bool {
+    match path.extension().and_then(|s| s.to_str()) {
+        Some("pgp") | Some("gpg") => false,
+        Some("asc") => true,
+        _ => {
+            eprintln!("unable to determine whether to armor file: {path:?}");
+            eprintln!("use .gpg, .pgp, or .asc extension, or `armor=true`");
+            eprintln!("defaulting to armored");
+            true
+        }
+    }
+}
+
+fn do_encrypt_to(
+    mnemonic: &keyfork_mnemonic::Mnemonic,
+    path: &Path,
+    options: &StringMap,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let policy = StandardPolicy::new();
+
+    let output_file = determine_valid_output_path(path, "enc", options.get("output"));
+
+    let is_armored =
+        options.get("armor").is_some_and(|a| a == "true") || is_extension_armored(&output_file);
+
+    let certs = OpenPGP::discover_certs(path)?;
+    let valid_certs = certs
+        .iter()
+        .map(|c| c.with_policy(&policy, None))
+        .collect::<openpgp::Result<Vec<_>>>()?;
+    let recipients = valid_certs.iter().flat_map(|valid_cert| {
+        let keys = valid_cert.keys().alive().for_storage_encryption();
+        keys.map(|key| Recipient::new(key.keyid(), key.key()))
+    });
+
+    let mut output = vec![];
+    let message = Message::new(&mut output);
+    let encrypted_message = Encryptor2::for_recipients(message, recipients).build()?;
+    let mut literal_message = LiteralWriter::new(encrypted_message).build()?;
+    literal_message.write_all(mnemonic.to_string().as_bytes())?;
+    literal_message.write_all(b"\n")?;
+    literal_message.finalize()?;
+
+    let mut file = File::create_new(&output_file)?;
+    if is_armored {
+        let mut writer = Writer::new(file, Kind::Message)?;
+        writer.write_all(&output)?;
+        writer.finalize()?;
+    } else {
+        file.write_all(&output)?;
+    }
+
+    Ok(())
+}
+
+fn do_encrypt_to_self(
+    mnemonic: &keyfork_mnemonic::Mnemonic,
+    path: &Path,
+    options: &StringMap,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let output_file = determine_valid_output_path(path, "enc", options.get("output"));
+
+    let is_armored =
+        options.get("armor").is_some_and(|a| a == "true") || is_extension_armored(&output_file);
+
+    let account = options
+        .get("account")
+        .map(|account| u32::from_str(account))
+        .transpose()?
+        .unwrap_or(0);
+    let account_index = keyfork_derive_util::DerivationIndex::new(account, true)?;
+
+    let userid = options
+        .get("userid")
+        .map(|userid| UserID::from(userid.as_str()));
+
+    let subkeys = [
+        KeyFlags::empty().set_certification(),
+        KeyFlags::empty().set_signing(),
+        KeyFlags::empty()
+            .set_transport_encryption()
+            .set_storage_encryption(),
+        KeyFlags::empty().set_authentication(),
+    ];
+
+    let seed = mnemonic.generate_seed(None);
+    let xprv = XPrv::new(seed)?;
+    let derivation_path = keyfork_derive_path_data::paths::OPENPGP
+        .clone()
+        .chain_push(account_index);
+
+    let cert = keyfork_derive_openpgp::derive(
+        xprv.derive_path(&derivation_path)?,
+        &subkeys,
+        &userid.unwrap_or(UserID::from("Keyfork-Generated Key")),
+    )?;
+
+    let mut file = File::create_new(path)?;
+    if is_armored {
+        let mut writer = Writer::new(file, Kind::PublicKey)?;
+        cert.serialize(&mut writer)?;
+        writer.finalize()?;
+    } else {
+        cert.serialize(&mut file)?;
+    }
+
+    // a sneaky bit of DRY
+    do_encrypt_to(
+        mnemonic,
+        path,
+        &StringMap::from([(
+            String::from("output"),
+            output_file.to_string_lossy().to_string(),
+        )]),
+    )?;
+
+    Ok(())
+}
+
+#[derive(thiserror::Error, Debug)]
+#[error("Either the threshold(m) or the max(n) values are missing")]
+struct MissingThresholdOrMax;
+
+fn do_shard(
+    mnemonic: &keyfork_mnemonic::Mnemonic,
+    path: &Path,
+    options: &StringMap,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let output_file = determine_valid_output_path(path, "shard", options.get("output"));
+
+    let is_armored =
+        options.get("armor").is_some_and(|a| a == "true") || is_extension_armored(&output_file);
+
+    let threshold = options
+        .get("threshold")
+        .or_else(|| options.get("m"))
+        .map(|s| u8::from_str(s))
+        .transpose()?;
+
+    let max = options
+        .get("max")
+        .or_else(|| options.get("n"))
+        .map(|s| u8::from_str(s))
+        .transpose()?;
+
+    let certs = OpenPGP::discover_certs(path)?;
+
+    // if neither are set: false
+    // if both are set: false
+    // if only one is set: true
+
+    if threshold.is_some() ^ max.is_some() {
+        return Err(MissingThresholdOrMax)?;
+    }
+
+    let (threshold, max) = match threshold.zip(max) {
+        Some(t) => t,
+        None => {
+            let len = u8::try_from(certs.len())?;
+            (len, len)
+        }
+    };
+
+    let openpgp = keyfork_shard::openpgp::OpenPGP;
+
+    let mut output = vec![];
+    openpgp.shard_and_encrypt(threshold, max, mnemonic.as_bytes(), &certs[..], &mut output)?;
+
+    let mut file = File::create_new(&output_file)?;
+    if is_armored {
+        file.write_all(&output)?;
+    } else {
+        todo!("keyfork does not handle binary shardfiles");
+        /*
+         * NOTE: this code works, but can't be recombined by Keyfork.
+         * therefore, we'll error, before someone tries to use it.
+        let mut dearmor = Reader::from_bytes(&output, ReaderMode::Tolerant(None));
+        std::io::copy(&mut dearmor, &mut file)?;
+        */
+    }
+
+    Ok(())
+}
+
+fn do_shard_to(
+    mnemonic: &keyfork_mnemonic::Mnemonic,
+    path: &Path,
+    options: &StringMap,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let output_file = determine_valid_output_path(path, "new", options.get("output"));
+
+    let is_armored =
+        options.get("armor").is_some_and(|a| a == "true") || is_extension_armored(&output_file);
+
+    let openpgp = keyfork_shard::openpgp::OpenPGP;
+    let prompt = default_handler()?;
+
+    let input = File::open(path)?;
+    let (threshold, certs) = openpgp.decrypt_metadata_from_file(
+        Some(&[][..]), // the things i must do to avoid qualifying types.
+        input,
+        prompt,
+    )?;
+
+    let mut output = vec![];
+    openpgp.shard_and_encrypt(
+        threshold,
+        u8::try_from(certs.len())?,
+        mnemonic.as_bytes(),
+        &certs[..],
+        &mut output,
+    )?;
+
+    let mut file = File::create_new(&output_file)?;
+    if is_armored {
+        file.write_all(&output)?;
+    } else {
+        todo!("keyfork does not handle binary shardfiles");
+        /*
+         * NOTE: this code works, but can't be recombined by Keyfork.
+         * therefore, we'll error, before someone tries to use it.
+        let mut dearmor = Reader::from_bytes(&output, ReaderMode::Tolerant(None));
+        std::io::copy(&mut dearmor, &mut file)?;
+        */
+    }
+
+    Ok(())
+}
+
+#[derive(thiserror::Error, Debug)]
+#[error("missing key: {0}")]
+struct MissingKey(&'static str);
+
+fn do_provision(
+    mnemonic: &keyfork_mnemonic::Mnemonic,
+    provisioner: &provision::Provisioner,
+    options: &StringMap,
+) -> Result<(), Box<dyn std::error::Error>> {
+    let mut options = options.clone();
+    let account = options
+        .remove("account")
+        .map(|account| u32::from_str(&account))
+        .transpose()?
+        .unwrap_or(0);
+    let identifier = options
+        .remove("identifier")
+        .ok_or(MissingKey("identifier"))?
+        .split(',')
+        .map(String::from)
+        .collect::<Vec<_>>();
+    let count = options
+        .remove("count")
+        .map(|count| usize::from_str(&count))
+        .transpose()?
+        .unwrap_or(identifier.len());
+
+    for (_, identifier) in (0..count).zip(identifier.into_iter()) {
+        let provisioner_config = config::Provisioner {
+            account,
+            identifier,
+            metadata: Some(options.clone()),
+        };
+
+        provisioner.provision_with_mnemonic(mnemonic, provisioner_config.clone())?;
+    }
+
+    Ok(())
+}
+
 impl MnemonicSubcommands {
     pub fn handle(
         &self,
         _m: &Mnemonic,
         _keyfork: &Keyfork,
-    ) -> Result<String, Box<dyn std::error::Error>> {
+    ) -> Result<(), Box<dyn std::error::Error>> {
         match self {
-            MnemonicSubcommands::Generate { source, size } => source.handle(size),
+            MnemonicSubcommands::Generate {
+                source,
+                size,
+                encrypt_to,
+                shard_to,
+                shard,
+                encrypt_to_self,
+                provision,
+            } => {
+                // NOTE: We should never have a case where there's Some() of empty vec, but
+                // we will make sure to check it just in case.
+                let mut will_print_mnemonic =
+                    encrypt_to.is_none() || encrypt_to.as_ref().is_some_and(|e| e.is_empty());
+                will_print_mnemonic = will_print_mnemonic && shard_to.is_none()
+                    || shard_to.as_ref().is_some_and(|s| s.is_empty());
+                will_print_mnemonic = will_print_mnemonic && shard.is_none()
+                    || shard.as_ref().is_some_and(|s| s.is_empty());
+                will_print_mnemonic = will_print_mnemonic
+                    && (encrypt_to_self.as_ref().is_none() || provision.as_ref().is_none());
+
+                let mnemonic = source.handle(size)?;
+
+                if let Some(encrypt_to) = encrypt_to {
+                    for entry in encrypt_to {
+                        do_encrypt_to(&mnemonic, &entry.inner, &entry.values)?;
+                    }
+                }
+
+                if let Some(encrypt_to_self) = encrypt_to_self {
+                    do_encrypt_to_self(&mnemonic, &encrypt_to_self.inner, &encrypt_to_self.values)?;
+                }
+
+                if let Some(provisioner) = provision {
+                    do_provision(&mnemonic, &provisioner.inner, &provisioner.values)?;
+                }
+
+                if let Some(shard_to) = shard_to {
+                    for entry in shard_to {
+                        do_shard_to(&mnemonic, &entry.inner, &entry.values)?;
+                    }
+                }
+
+                if let Some(shard) = shard {
+                    for entry in shard {
+                        do_shard(&mnemonic, &entry.inner, &entry.values)?;
+                    }
+                }
+
+                if will_print_mnemonic {
+                    println!("{}", mnemonic);
+                }
+                Ok(())
+            }
         }
     }
 }

crates/keyfork/src/cli/mod.rs

@@ -79,8 +79,7 @@ impl KeyforkCommands {
                 d.handle(keyfork)?;
             }
             KeyforkCommands::Mnemonic(m) => {
-                let response = m.command.handle(m, keyfork)?;
-                println!("{response}");
+                m.command.handle(m, keyfork)?;
             }
             KeyforkCommands::Shard(s) => {
                 s.command.handle(s, keyfork)?;

crates/keyfork/src/cli/provision/mod.rs

@@ -3,9 +3,15 @@ use crate::config;
 
 use clap::{builder::PossibleValue, Parser, Subcommand, ValueEnum};
 
+use keyfork_derive_util::{DerivationIndex, ExtendedPrivateKey};
+
+mod openpgp;
+
+type Identifier = (String, Option<String>);
+
 #[derive(Debug, Clone)]
 pub enum Provisioner {
-    OpenPGPCard(OpenPGPCard),
+    OpenPGPCard(openpgp::OpenPGPCard),
 }
 
 impl std::fmt::Display for Provisioner {
@@ -17,25 +23,52 @@ impl std::fmt::Display for Provisioner {
 }
 
 impl Provisioner {
-    fn discover(&self) -> Vec<(String, Option<String>)> {
+    pub fn discover(&self) -> Result<Vec<Identifier>, Box<dyn std::error::Error>> {
         match self {
             Provisioner::OpenPGPCard(o) => o.discover(),
         }
     }
 
-    fn provision(
+    pub fn provision(
         &self,
         provisioner: config::Provisioner,
     ) -> Result<(), Box<dyn std::error::Error>> {
         match self {
-            Provisioner::OpenPGPCard(o) => o.provision(provisioner),
+            Provisioner::OpenPGPCard(o) => {
+                type Prv = <openpgp::OpenPGPCard as ProvisionExec>::PrivateKey;
+                type XPrv = ExtendedPrivateKey<Prv>;
+                let account_index = DerivationIndex::new(provisioner.account, true)?;
+                let path = <openpgp::OpenPGPCard as ProvisionExec>::derivation_prefix()
+                    .chain_push(account_index);
+                let mut client = keyforkd_client::Client::discover_socket()?;
+                let xprv: XPrv = client.request_xprv(&path)?;
+                o.provision(xprv, provisioner)
+            }
+        }
+    }
+
+    pub fn provision_with_mnemonic(
+        &self,
+        mnemonic: &keyfork_mnemonic::Mnemonic,
+        provisioner: config::Provisioner,
+    ) -> Result<(), Box<dyn std::error::Error>> {
+        match self {
+            Provisioner::OpenPGPCard(o) => {
+                type Prv = <openpgp::OpenPGPCard as ProvisionExec>::PrivateKey;
+                type XPrv = ExtendedPrivateKey<Prv>;
+                let account_index = DerivationIndex::new(provisioner.account, true)?;
+                let path = <openpgp::OpenPGPCard as ProvisionExec>::derivation_prefix()
+                    .chain_push(account_index);
+                let xprv = XPrv::new(mnemonic.generate_seed(None))?.derive_path(&path)?;
+                o.provision(xprv, provisioner)
+            }
         }
     }
 }
 
 impl ValueEnum for Provisioner {
     fn value_variants<'a>() -> &'a [Self] {
-        &[Self::OpenPGPCard(OpenPGPCard)]
+        &[Self::OpenPGPCard(openpgp::OpenPGPCard)]
     }
 
     fn to_possible_value(&self) -> Option<PossibleValue> {
@@ -45,39 +78,36 @@ impl ValueEnum for Provisioner {
     }
 }
 
-trait ProvisionExec {
-    /// Discover all known places the formatted key can be deployed to.
-    fn discover(&self) -> Vec<(String, Option<String>)> {
-        vec![]
+#[derive(Debug, thiserror::Error)]
+#[error("The given value could not be matched as a provisioner: {0} ({1})")]
+pub struct ProvisionerFromStrError(String, String);
+
+impl std::str::FromStr for Provisioner {
+    type Err = ProvisionerFromStrError;
+
+    fn from_str(s: &str) -> Result<Self, Self::Err> {
+        <Provisioner as ValueEnum>::from_str(s, false)
+            .map_err(|e| ProvisionerFromStrError(s.to_string(), e))
     }
+}
+
+trait ProvisionExec {
+    type PrivateKey: keyfork_derive_util::PrivateKey + Clone;
+
+    /// Discover all known places the formatted key can be deployed to.
+    fn discover(&self) -> Result<Vec<Identifier>, Box<dyn std::error::Error>> {
+        Ok(vec![])
+    }
+
+    /// Return the derivation path for deriving keys.
+    fn derivation_prefix() -> keyfork_derive_util::DerivationPath;
 
     /// Derive a key and deploy it to a target.
-    fn provision(&self, p: config::Provisioner) -> Result<(), Box<dyn std::error::Error>>;
-}
-
-#[derive(Clone, Debug)]
-pub struct OpenPGPCard;
-
-impl ProvisionExec for OpenPGPCard {
-    fn discover(&self) -> Vec<(String, Option<String>)> {
-        /*
-        vec![
-            (
-                "0006:26144195".to_string(),
-                Some("Yubicats Heywood".to_string()),
-            ),
-            (
-                "0006:2614419y".to_string(),
-                Some("Yubicats Heywood".to_string()),
-            ),
-        ]
-        */
-        vec![]
-    }
-
-    fn provision(&self, _p: config::Provisioner) -> Result<(), Box<dyn std::error::Error>> {
-        todo!()
-    }
+    fn provision(
+        &self,
+        xprv: keyfork_derive_util::ExtendedPrivateKey<Self::PrivateKey>,
+        p: config::Provisioner,
+    ) -> Result<(), Box<dyn std::error::Error>>;
 }
 
 #[derive(Subcommand, Clone, Debug)]
@@ -118,7 +148,6 @@ impl TryFrom<Provision> for config::Provisioner {
 
     fn try_from(value: Provision) -> Result<Self, Self::Error> {
         Ok(Self {
-            name: value.provisioner_name.to_string(),
             account: value.account_id.ok_or(MissingField("account_id"))?,
             identifier: value.identifier.ok_or(MissingField("identifier"))?,
             metadata: Default::default(),
@@ -130,7 +159,7 @@ impl Provision {
     pub fn handle(&self, _keyfork: &Keyfork) -> Result<(), Box<dyn std::error::Error>> {
         match self.subcommand {
             Some(ProvisionSubcommands::Discover) => {
-                let mut iter = self.provisioner_name.discover().into_iter().peekable();
+                let mut iter = self.provisioner_name.discover()?.into_iter().peekable();
                 while let Some((identifier, context)) = iter.next() {
                     println!("Identifier: {identifier}");
                     if let Some(context) = context {

crates/keyfork/src/cli/provision/openpgp.rs

@@ -0,0 +1,111 @@
+use super::ProvisionExec;
+use crate::{config, openpgp_card::factory_reset_current_card};
+
+use card_backend_pcsc::PcscBackend;
+use keyfork_derive_openpgp::{
+    openpgp::{packet::UserID, types::KeyFlags},
+    XPrv,
+};
+use keyfork_prompt::{
+    default_handler, prompt_validated_passphrase,
+    validators::{SecurePinValidator, Validator},
+};
+use openpgp_card_sequoia::{state::Open, Card};
+
+#[derive(Clone, Debug)]
+pub struct OpenPGPCard;
+
+#[derive(thiserror::Error, Debug)]
+#[error("Provisioner was unable to find a matching smartcard")]
+struct NoMatchingSmartcard;
+
+impl ProvisionExec for OpenPGPCard {
+    type PrivateKey = keyfork_derive_openpgp::XPrvKey;
+
+    fn discover(&self) -> Result<Vec<(String, Option<String>)>, Box<dyn std::error::Error>> {
+        let mut idents = vec![];
+        for backend in PcscBackend::cards(None)? {
+            let backend = backend?;
+            let mut card = Card::<Open>::new(backend)?;
+            let mut transaction = card.transaction()?;
+            let identifier = transaction.application_identifier()?.ident();
+            let name = transaction.cardholder_name()?;
+            let name = (!name.is_empty()).then_some(name);
+            idents.push((identifier, name));
+        }
+        Ok(idents)
+    }
+
+    fn derivation_prefix() -> keyfork_derive_util::DerivationPath {
+        keyfork_derive_path_data::paths::OPENPGP.clone()
+    }
+
+    fn provision(
+        &self,
+        xprv: XPrv,
+        provisioner: config::Provisioner,
+    ) -> Result<(), Box<dyn std::error::Error>> {
+        let mut pm = default_handler()?;
+        let user_pin_validator = SecurePinValidator {
+            min_length: Some(6),
+            ..Default::default()
+        }
+        .to_fn();
+        let admin_pin_validator = SecurePinValidator {
+            min_length: Some(8),
+            ..Default::default()
+        }
+        .to_fn();
+
+        let user_pin = prompt_validated_passphrase(
+            &mut *pm,
+            "Please enter the new smartcard User PIN: ",
+            3,
+            &user_pin_validator,
+        )?;
+        let admin_pin = prompt_validated_passphrase(
+            &mut *pm,
+            "Please enter the new smartcard Admin PIN: ",
+            3,
+            &admin_pin_validator,
+        )?;
+
+        let mut has_provisioned = false;
+
+        for backend in PcscBackend::cards(None)? {
+            let backend = backend?;
+
+            let subkeys = vec![
+                KeyFlags::empty().set_certification(),
+                KeyFlags::empty().set_signing(),
+                KeyFlags::empty()
+                    .set_transport_encryption()
+                    .set_storage_encryption(),
+                KeyFlags::empty().set_authentication(),
+            ];
+
+            // NOTE: This User ID doesn't have meaningful context on the card.
+            // To give it a reasonable name, use `keyfork derive openpgp` or some other system that
+            // generates the OpenPGP certificate.
+            let userid = UserID::from("Keyfork-Provisioned Key");
+            let cert = keyfork_derive_openpgp::derive(xprv.clone(), &subkeys, &userid)?;
+
+            let result = factory_reset_current_card(
+                &mut |identifier| { identifier == provisioner.identifier },
+                user_pin.trim(),
+                admin_pin.trim(),
+                &cert,
+                &keyfork_derive_openpgp::openpgp::policy::StandardPolicy::new(),
+                backend,
+            )?;
+
+            has_provisioned = has_provisioned || result;
+        }
+
+        if !has_provisioned {
+            return Err(NoMatchingSmartcard)?;
+        }
+
+        Ok(())
+    }
+}

crates/keyfork/src/cli/wizard.rs

@@ -1,18 +1,18 @@
 use super::Keyfork;
+use crate::openpgp_card::factory_reset_current_card;
 use clap::{Args, Parser, Subcommand};
 use std::{collections::HashSet, fs::File, io::IsTerminal, path::PathBuf};
 
 use card_backend_pcsc::PcscBackend;
-use openpgp_card_sequoia::{state::Open, types::KeyType, Card};
 
 use keyfork_derive_openpgp::{
     openpgp::{
         self,
         armor::{Kind, Writer},
-        packet::{UserID, signature::SignatureBuilder},
-        serialize::Marshal,
-        types::{SignatureType, KeyFlags},
+        packet::{signature::SignatureBuilder, UserID},
         policy::StandardPolicy,
+        serialize::Marshal,
+        types::{KeyFlags, SignatureType},
         Cert,
     },
     XPrv,
@@ -56,54 +56,6 @@ fn derive_key(seed: [u8; 32], index: u8) -> Result<Cert> {
     Ok(cert)
 }
 
-// TODO: extract into crate
-/// Factory reset the current card so long as it does not match the last-used backend.
-fn factory_reset_current_card(
-    seen_cards: &mut HashSet<String>,
-    user_pin: &str,
-    admin_pin: &str,
-    cert: &Cert,
-    card_backend: PcscBackend,
-) -> Result<()> {
-    let policy = openpgp::policy::NullPolicy::new();
-    let valid_cert = cert.with_policy(&policy, None)?;
-    let signing_key = valid_cert
-        .keys()
-        .for_signing()
-        .secret()
-        .next()
-        .expect("no signing key found");
-    let decryption_key = valid_cert
-        .keys()
-        .for_storage_encryption()
-        .secret()
-        .next()
-        .expect("no decryption key found");
-    let authentication_key = valid_cert
-        .keys()
-        .for_authentication()
-        .secret()
-        .next()
-        .expect("no authentication key found");
-    let mut card = Card::<Open>::new(card_backend)?;
-    let mut transaction = card.transaction()?;
-    let application_identifier = transaction.application_identifier()?.ident();
-    if seen_cards.contains(&application_identifier) {
-        // we were given the same card, error
-        panic!("Previously used card {application_identifier} was reused");
-    } else {
-        seen_cards.insert(application_identifier);
-    }
-    transaction.factory_reset()?;
-    let mut admin = transaction.to_admin_card("12345678")?;
-    admin.upload_key(signing_key, KeyType::Signing, None)?;
-    admin.upload_key(decryption_key, KeyType::Decryption, None)?;
-    admin.upload_key(authentication_key, KeyType::Authentication, None)?;
-    transaction.change_user_pin("123456", user_pin)?;
-    transaction.change_admin_pin("12345678", admin_pin)?;
-    Ok(())
-}
-
 #[derive(Subcommand, Clone, Debug)]
 pub enum WizardSubcommands {
     GenerateShardSecret(GenerateShardSecret),
@@ -178,6 +130,8 @@ impl WizardSubcommands {
 
 fn cross_sign_certs(certs: &mut [Cert]) -> Result<(), Box<dyn std::error::Error>> {
     let policy = StandardPolicy::new();
+
+    #[allow(clippy::unnecessary_to_owned)]
     for signing_cert in certs.to_vec() {
         let mut certify_key = signing_cert
             .with_policy(&policy, None)?
@@ -198,7 +152,7 @@ fn cross_sign_certs(certs: &mut [Cert]) -> Result<(), Box<dyn std::error::Error>
             let signature = sb.sign_userid_binding(
                 &mut certify_key,
                 signable_cert.primary_key().key(),
-                &*userid,
+                &userid,
             )?;
             let changed;
             (*signable_cert, changed) = signable_cert.clone().insert_packets2(signature)?;
@@ -266,10 +220,20 @@ impl GenerateShardSecret {
                     &admin_pin_validator,
                 )?;
                 factory_reset_current_card(
-                    &mut seen_cards,
+                    &mut |application_identifier| {
+                        if seen_cards.contains(&application_identifier) {
+                            // we were given the same card, error
+                            // we're gonna panic because this is a significant error
+                            panic!("Previously used card {application_identifier} was reused");
+                        } else {
+                            seen_cards.insert(application_identifier);
+                            true
+                        }
+                    },
                     user_pin.trim(),
                     admin_pin.trim(),
                     &cert,
+                    &openpgp::policy::NullPolicy::new(),
                     card_backend,
                 )?;
             }

crates/keyfork/src/config.rs

@@ -2,20 +2,19 @@ use std::collections::HashMap;
 
 use serde::{Deserialize, Serialize};
 
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, Clone)]
 pub struct Mnemonic {
     pub hash: String,
 }
 
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, Clone)]
 pub struct Provisioner {
-    pub name: String,
     pub account: u32,
     pub identifier: String,
     pub metadata: Option<HashMap<String, String>>,
 }
 
-#[derive(Serialize, Deserialize)]
+#[derive(Serialize, Deserialize, Clone)]
 pub struct Config {
     pub mnemonic: Mnemonic,
     pub provisioner: Vec<Provisioner>,

crates/keyfork/src/main.rs

@@ -10,6 +10,8 @@ use keyfork_bin::{Bin, ClosureBin};
 
 mod cli;
 mod config;
+pub mod clap_ext;
+mod openpgp_card;
 
 fn main() -> ExitCode {
     let bin = ClosureBin::new(|| {

crates/keyfork/src/openpgp_card.rs

@@ -0,0 +1,51 @@
+use card_backend_pcsc::PcscBackend;
+use openpgp_card_sequoia::{state::Open, types::KeyType, Card};
+use keyfork_derive_openpgp::openpgp::{Cert, policy::Policy};
+
+/// Factory reset the current card so long as it does not match the last-used backend.
+///
+/// The return value of `false` means the filter was matched, whereas `true` means it was
+/// successfully provisioned.
+pub fn factory_reset_current_card(
+    card_filter: &mut dyn FnMut(String) -> bool,
+    user_pin: &str,
+    admin_pin: &str,
+    cert: &Cert,
+    policy: &dyn Policy,
+    card_backend: PcscBackend,
+) -> Result<bool, Box<dyn std::error::Error>> {
+    let valid_cert = cert.with_policy(policy, None)?;
+    let signing_key = valid_cert
+        .keys()
+        .for_signing()
+        .secret()
+        .next()
+        .expect("no signing key found");
+    let decryption_key = valid_cert
+        .keys()
+        .for_storage_encryption()
+        .secret()
+        .next()
+        .expect("no decryption key found");
+    let authentication_key = valid_cert
+        .keys()
+        .for_authentication()
+        .secret()
+        .next()
+        .expect("no authentication key found");
+    let mut card = Card::<Open>::new(card_backend)?;
+    let mut transaction = card.transaction()?;
+    let application_identifier = transaction.application_identifier()?.ident();
+    if !card_filter(application_identifier) {
+        return Ok(false);
+    }
+    transaction.factory_reset()?;
+    let mut admin = transaction.to_admin_card("12345678")?;
+    admin.upload_key(signing_key, KeyType::Signing, None)?;
+    admin.upload_key(decryption_key, KeyType::Decryption, None)?;
+    admin.upload_key(authentication_key, KeyType::Authentication, None)?;
+    transaction.change_user_pin("123456", user_pin)?;
+    transaction.change_admin_pin("12345678", admin_pin)?;
+    Ok(true)
+}
+