Add WIF derivation for transparent keys.

With @gmale

zcash_client_backend/Cargo.toml

@@ -48,7 +48,7 @@ zcash_proofs = { version = "0.5", path = "../zcash_proofs" }
 
 [features]
 transparent-inputs = ["ripemd160", "secp256k1"]
-test-dependencies = ["proptest", "zcash_primitives/test-dependencies"]
+test-dependencies = ["proptest", "zcash_primitives/test-dependencies", "hdwallet"]
 
 [badges]
 maintenance = { status = "actively-developed" }

zcash_client_backend/src/data_api.rs

@@ -412,6 +412,7 @@ pub mod testing {
             Ok(Vec::new())
         }
 
+        #[cfg(feature = "transparent-inputs")]
         fn get_spendable_transparent_utxos(
             &self,
             _address: &TransparentAddress,

zcash_client_backend/src/data_api/wallet.rs

@@ -308,6 +308,7 @@ where
 
     let mut builder = Builder::new(params.clone(), latest_scanned_height);
 
+    #[cfg(feature = "transparent-inputs")]
     for utxo in &utxos {
         let coin = TxOut {
             value: utxo.value,

zcash_client_backend/src/keys.rs

@@ -5,9 +5,9 @@ use zcash_primitives::zip32::{ChildIndex, ExtendedSpendingKey};
 #[cfg(feature = "transparent-inputs")]
 use {
     crate::wallet::AccountId,
-    bs58::decode::Error as Bs58Error,
+    bs58::{self, decode::Error as Bs58Error},
     hdwallet::{ExtendedPrivKey, KeyIndex},
-    secp256k1::{key::PublicKey, Secp256k1, SecretKey},
+    secp256k1::{key::PublicKey, key::SecretKey, Secp256k1},
     sha2::{Digest, Sha256},
     std::convert::TryInto,
     zcash_primitives::{consensus, legacy::TransparentAddress},
@@ -109,9 +109,55 @@ impl TryInto<SecretKey> for Wif {
 mod tests {
     use super::spending_key;
 
+    #[cfg(feature = "transparent-inputs")]
+    use {
+        super::{derive_secret_key_from_seed, derive_transparent_address_from_secret_key, Wif},
+        crate::{encoding::AddressCodec, wallet::AccountId},
+        secp256k1::key::SecretKey,
+        std::convert::TryInto,
+        zcash_primitives::consensus::MAIN_NETWORK,
+    };
+
     #[test]
     #[should_panic]
     fn spending_key_panics_on_short_seed() {
         let _ = spending_key(&[0; 31][..], 0, 0);
     }
+
+    #[cfg(feature = "transparent-inputs")]
+    #[test]
+    fn sk_to_wif() {
+        let seed_hex = "6ef5f84def6f4b9d38f466586a8380a38593bd47c8cda77f091856176da47f26b5bd1c8d097486e5635df5a66e820d28e1d73346f499801c86228d43f390304f";
+        let seed = hex::decode(&seed_hex).unwrap();
+        let sk = derive_secret_key_from_seed(&MAIN_NETWORK, &seed, AccountId(0), 0).unwrap();
+        assert_eq!(
+            Wif::from_secret_key(&sk, true).0,
+            "L4BvDC33yLjMRxipZvdiUmdYeRfZmR8viziwsVwe72zJdGbiJPv2".to_string()
+        );
+    }
+
+    #[cfg(feature = "transparent-inputs")]
+    #[test]
+    fn sk_to_taddr() {
+        let seed_hex = "6ef5f84def6f4b9d38f466586a8380a38593bd47c8cda77f091856176da47f26b5bd1c8d097486e5635df5a66e820d28e1d73346f499801c86228d43f390304f";
+        let seed = hex::decode(&seed_hex).unwrap();
+        let sk = derive_secret_key_from_seed(&MAIN_NETWORK, &seed, AccountId(0), 0).unwrap();
+        let taddr = derive_transparent_address_from_secret_key(sk);
+        assert_eq!(
+            taddr.encode(&MAIN_NETWORK),
+            "t1PKtYdJJHhc3Pxowmznkg7vdTwnhEsCvR4".to_string()
+        );
+    }
+
+    #[cfg(feature = "transparent-inputs")]
+    #[test]
+    fn sk_wif_to_taddr() {
+        let sk_wif = Wif("L4BvDC33yLjMRxipZvdiUmdYeRfZmR8viziwsVwe72zJdGbiJPv2".to_string());
+        let sk: SecretKey = sk_wif.try_into().expect("invalid wif");
+        let taddr = derive_transparent_address_from_secret_key(sk);
+        assert_eq!(
+            taddr.encode(&MAIN_NETWORK),
+            "t1PKtYdJJHhc3Pxowmznkg7vdTwnhEsCvR4".to_string()
+        );
+    }
 }