feat: Expose decode_seed functionality

Signed-off-by: Joonas Bergius <[email protected]>

src/jwk.rs

@@ -1,6 +1,6 @@
 use std::collections::BTreeMap;
 
-use crate::{err, from_public_key, from_seed, KeyPair, KeyPairType, Result};
+use crate::{decode_seed, err, from_public_key, KeyPair, KeyPairType, Result};
 use data_encoding::BASE64URL_NOPAD;
 use ed25519_dalek::{SigningKey, VerifyingKey};
 use serde::{Deserialize, Serialize};
@@ -42,7 +42,7 @@ pub struct JsonWebKey {
 
 impl JsonWebKey {
     pub fn from_seed(source: &str) -> Result<Self> {
-        let (prefix, seed) = from_seed(source)?;
+        let (prefix, seed) = decode_seed(source)?;
         let sk = SigningKey::from_bytes(&seed);
         let kp_type = &KeyPairType::from(prefix);
         let public_key = BASE64URL_NOPAD.encode(sk.verifying_key().as_bytes());

src/lib.rs

@@ -308,7 +308,7 @@ impl KeyPair {
 
     /// Attempts to produce a full key pair from the given encoded seed string
     pub fn from_seed(source: &str) -> Result<KeyPair> {
-        let (ty, seed) = from_seed(source)?;
+        let (ty, seed) = decode_seed(source)?;
 
         let signing_key = SigningKey::from_bytes(&seed);
 
@@ -364,8 +364,9 @@ fn from_public_key(source: &str) -> Result<(u8, [u8; 32])> {
     Ok((prefix, public_key))
 }
 
-/// Returns the type and the seed
-fn from_seed(source: &str) -> Result<(u8, [u8; 32])> {
+/// Attempts to decode the provided base32 encoded string into a valid prefix byte and the private key seed bytes.
+/// NOTE: This is considered an advanced use case, it's generally recommended to stick with [`KeyPair::from_seed`] instead.
+pub fn decode_seed(source: &str) -> Result<(u8, [u8; 32])> {
     if source.len() != ENCODED_SEED_LENGTH {
         let l = source.len();
         return Err(err!(InvalidKeyLength, "Bad seed length: {}", l));
@@ -441,6 +442,17 @@ mod tests {
     use super::*;
     use crate::error::ErrorKind;
 
+    #[test]
+    fn validate_decode_seed() {
+        let input_bytes = generate_seed_rand();
+        let seed = encode_seed(&KeyPairType::User, input_bytes.as_slice());
+
+        let (prefix, decoded_bytes) = decode_seed(&seed).unwrap();
+
+        assert_eq!(prefix, PREFIX_BYTE_USER);
+        assert_eq!(decoded_bytes, input_bytes);
+    }
+
     #[test]
     fn seed_encode_decode_round_trip() {
         let pair = KeyPair::new_user();

src/xkeys.rs

@@ -1,6 +1,6 @@
 use crate::{
-    decode_raw, encode, encode_prefix, encode_seed, err, from_seed, KeyPairType, PREFIX_BYTE_CURVE,
-    PREFIX_BYTE_PRIVATE,
+    decode_raw, decode_seed, encode, encode_prefix, encode_seed, err, KeyPairType,
+    PREFIX_BYTE_CURVE, PREFIX_BYTE_PRIVATE,
 };
 
 use super::Result;
@@ -86,7 +86,7 @@ impl XKey {
 
     /// Attempts to produce a full xkey pair from the given encoded seed string
     pub fn from_seed(source: &str) -> Result<Self> {
-        let (ty, seed) = from_seed(source)?;
+        let (ty, seed) = decode_seed(source)?;
 
         if ty != PREFIX_BYTE_CURVE {
             return Err(err!(