diff --git a/keyfork-shard/src/lib.rs b/keyfork-shard/src/lib.rs
index bb51102..5de6177 100644
--- a/keyfork-shard/src/lib.rs
+++ b/keyfork-shard/src/lib.rs
@@ -1,16 +1,17 @@
-use std::{
-    io::{stdin, stdout, Write},
-    str::FromStr,
-};
+use std::io::{stdin, stdout, Write};
 
 use aes_gcm::{
     aead::{Aead, AeadCore, OsRng},
     Aes256Gcm, KeyInit,
 };
 use hkdf::Hkdf;
-use sha2::Sha256;
 use keyfork_mnemonic_util::{Mnemonic, Wordlist};
-use keyfork_prompt::{qrencode, Message as PromptMessage, PromptManager};
+use keyfork_prompt::{
+    qrencode,
+    validators::{mnemonic::MnemonicSetValidator, Validator},
+    Message as PromptMessage, PromptManager,
+};
+use sha2::Sha256;
 use sharks::{Share, Sharks};
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
@@ -66,27 +67,17 @@ pub fn remote_decrypt(w: &mut impl Write) -> Result<(), Box<dyn std::error::Erro
             pm.prompt_message(&PromptMessage::Data(qrcode))?;
         }
 
-        let their_words = pm.prompt_wordlist("Their words: ", &wordlist)?;
+        let validator = MnemonicSetValidator {
+            word_lengths: [24, 48],
+        };
 
-        let mut pubkey_words = their_words.split_whitespace().take(24).peekable();
-        let mut payload_words = their_words.split_whitespace().skip(24).take(48).peekable();
-        let mut pubkey_mnemonic = String::new();
-        let mut payload_mnemonic = String::new();
-        while let Some(word) = pubkey_words.next() {
-            pubkey_mnemonic.push_str(word);
-            if pubkey_words.peek().is_some() {
-                pubkey_mnemonic.push(' ');
-            }
-        }
-        while let Some(word) = payload_words.next() {
-            payload_mnemonic.push_str(word);
-            if payload_words.peek().is_some() {
-                payload_mnemonic.push(' ');
-            }
-        }
+        let [pubkey_mnemonic, payload_mnemonic] =
+            pm.prompt_validated_wordlist("Their words: ", &wordlist, 3, validator.to_fn())?;
 
-        let their_key = Mnemonic::from_str(&pubkey_mnemonic)?.entropy();
-        let their_key: [u8; 32] = their_key.try_into().map_err(|_| InvalidMnemonicData)?;
+        let their_key: [u8; 32] = pubkey_mnemonic
+            .entropy()
+            .try_into()
+            .map_err(|_| InvalidMnemonicData)?;
 
         let shared_secret = our_key
             .diffie_hellman(&PublicKey::from(their_key))
@@ -94,10 +85,9 @@ pub fn remote_decrypt(w: &mut impl Write) -> Result<(), Box<dyn std::error::Erro
         let hkdf = Hkdf::<Sha256>::new(None, &shared_secret);
         let mut hkdf_output = [0u8; 256 / 8];
         hkdf.expand(&[], &mut hkdf_output)?;
-        let shared_key =
-            Aes256Gcm::new_from_slice(&hkdf_output)?;
+        let shared_key = Aes256Gcm::new_from_slice(&hkdf_output)?;
 
-        let payload = Mnemonic::from_str(&payload_mnemonic)?.entropy();
+        let payload = payload_mnemonic.entropy();
         let payload =
             shared_key.decrypt(&nonce, &payload[..payload[payload.len() - 1] as usize])?;
         assert_eq!(HUNK_VERSION, payload[0], "Incompatible hunk version");
diff --git a/keyfork-shard/src/openpgp.rs b/keyfork-shard/src/openpgp.rs
index daaba77..1b217e8 100644
--- a/keyfork-shard/src/openpgp.rs
+++ b/keyfork-shard/src/openpgp.rs
@@ -11,13 +11,16 @@ use aes_gcm::{
     Aes256Gcm, Error as AesError, KeyInit, Nonce,
 };
 use hkdf::{Hkdf, InvalidLength as HkdfInvalidLength};
-use sha2::Sha256;
 use keyfork_derive_openpgp::derive_util::{
     request::{DerivationAlgorithm, DerivationRequest},
     DerivationPath,
 };
 use keyfork_mnemonic_util::{Mnemonic, MnemonicFromStrError, MnemonicGenerationError, Wordlist};
-use keyfork_prompt::{qrencode, Error as PromptError, Message as PromptMessage, PromptManager};
+use keyfork_prompt::{
+    qrencode,
+    validators::{mnemonic::MnemonicSetValidator, Validator},
+    Error as PromptError, Message as PromptMessage, PromptManager,
+};
 use openpgp::{
     armor::{Kind, Writer},
     cert::{Cert, CertParser, ValidCert},
@@ -35,6 +38,7 @@ use openpgp::{
     Fingerprint, KeyID, PacketPile,
 };
 pub use sequoia_openpgp as openpgp;
+use sha2::Sha256;
 use sharks::{Share, Sharks};
 use x25519_dalek::{EphemeralSecret, PublicKey};
 
@@ -51,7 +55,7 @@ use smartcard::SmartcardManager;
 const SHARD_METADATA_VERSION: u8 = 1;
 const SHARD_METADATA_OFFSET: usize = 2;
 
-use super::{SharksError, InvalidMnemonicData, HUNK_VERSION};
+use super::{InvalidMnemonicData, SharksError, HUNK_VERSION};
 
 // 256 bit share is 49 bytes + some amount of hunk bytes, gives us reasonable padding
 const ENC_LEN: u8 = 4 * 16;
@@ -407,28 +411,17 @@ pub fn decrypt(
 ) -> Result<()> {
     let mut pm = PromptManager::new(stdin(), stdout())?;
     let wordlist = Wordlist::default();
-    let their_words = pm.prompt_wordlist("Their words: ", &wordlist)?;
-    let mut nonce_words = their_words.split_whitespace().take(9).peekable();
-    let mut pubkey_words = their_words.split_whitespace().skip(9).take(24).peekable();
-    let mut nonce_mnemonic = String::new();
-    let mut pubkey_mnemonic = String::new();
-    while let Some(word) = nonce_words.next() {
-        nonce_mnemonic.push_str(word);
-        if nonce_words.peek().is_some() {
-            nonce_mnemonic.push(' ');
-        }
-    }
-    while let Some(word) = pubkey_words.next() {
-        pubkey_mnemonic.push_str(word);
-        if pubkey_words.peek().is_some() {
-            pubkey_mnemonic.push(' ');
-        }
-    }
-    let their_key = Mnemonic::from_str(&pubkey_mnemonic)?.entropy();
-    let their_key: [u8; 32] = their_key
+    let validator = MnemonicSetValidator {
+        word_lengths: [9, 24],
+    };
+    let [nonce_mnemonic, pubkey_mnemonic] =
+        pm.prompt_validated_wordlist("Their words: ", &wordlist, 3, validator.to_fn())?;
+
+    let their_key: [u8; 32] = pubkey_mnemonic
+        .entropy()
         .try_into()
         .map_err(|_| InvalidMnemonicData)?;
-    let their_nonce = Mnemonic::from_str(&nonce_mnemonic)?.entropy();
+    let their_nonce = nonce_mnemonic.entropy();
     let their_nonce = Nonce::<U12>::from_slice(&their_nonce);
 
     let our_key = EphemeralSecret::random();
@@ -450,8 +443,7 @@ pub fn decrypt(
     let hkdf = Hkdf::<Sha256>::new(None, &shared_secret);
     let mut hkdf_output = [0u8; 256 / 8];
     hkdf.expand(&[], &mut hkdf_output)?;
-    let shared_key =
-        Aes256Gcm::new_from_slice(&hkdf_output)?;
+    let shared_key = Aes256Gcm::new_from_slice(&hkdf_output)?;
 
     let bytes = shared_key.encrypt(their_nonce, share.as_slice())?;
     shared_key.decrypt(their_nonce, &bytes[..])?;
@@ -568,9 +560,7 @@ pub fn combine(
         return Err(Error::InvalidSecret(derived_fp, expected_fp));
     }
 
-    output
-        .write_all(&secret)
-        .map_err(Error::Io)?;
+    output.write_all(&secret).map_err(Error::Io)?;
 
     Ok(())
 }