Add function to validate taddr privkeys

src/settings.cpp

@@ -435,6 +435,27 @@ double Settings::getMinerFee() {
     return 0.0001;
 }
 
+bool Settings::isValidTransparentPrivateKey(QString pk) {
+    if (pk.length() > 52) {
+        DEBUG("privkey invalid, too long");
+        return false;
+    }
+
+    if (pk.length() < 51) {
+        DEBUG("privkey invalid, too short");
+        return false;
+    }
+
+    // TODO: can a taddr privkey start with anything else?
+    if (pk.startsWith("U") || pk.startsWith("5") || pk.startsWith("L") || pk.startsWith("K") || pk.startsWith("7")) {
+        // TODO: verify only contains base58 characters
+        return true;
+    } else {
+        DEBUG("privkey invalid, wrong prefix");
+        return false;
+    }
+}
+
 bool Settings::isValidSaplingPrivateKey(QString pk) {
     if (isTestnet()) {
         QRegExp zspkey("^secret-extended-key-test[0-9a-z]{278}$", Qt::CaseInsensitive);

src/settings.h

@@ -50,6 +50,7 @@ public:
     bool    isSproutAddress(QString addr);
 
     bool    isValidSaplingPrivateKey(QString pk);
+    bool    isValidTransparentPrivateKey(QString pk);
 
     bool    isSyncing();
     void    setSyncing(bool syncing);