feat(detectors): add Nigerian fintech & betting credential detector

Adds high-signal detector for:
• Paystack (live/test keys)
• Flutterwave/Rave
• Remita merchant+hash
• Interswitch MAC keys
• SportyBet/BetKing tokens

Written by @LloydCoder (Tinlance) after shipping the same in Nuclei templates.
Zero false positives expected due to keyword pre-filtering.
🇳🇬

Author: LloydCoder

pkg/detectors/nigerianfintech/nigerianfintech.go

@@ -0,0 +1,76 @@
+package nigerianfintech
+
+import (
+    "context"
+    "regexp"
+
+    "github.com/trufflesecurity/trufflehog/v3/pkg/common"
+    "github.com/trufflesecurity/trufflehog/v3/pkg/detectors"
+    "github.com/trufflesecurity/trufflehog/v3/pkg/pb/detectorspb"
+)
+
+type scanner struct{}
+
+// Ensure the detector satisfies the interface at compile time.
+var _ detectors.Detector = (*scanner)(nil)
+
+func (s scanner) ID() int { return 987 }
+
+func (s scanner) Type() detectorspb.DetectorType {
+    return detectorspb.DetectorType_CustomRegex
+}
+
+func (s scanner) Description() string {
+    return "Detects exposed Nigerian fintech & betting credentials (Paystack, Flutterwave, Remita, Interswitch, SportyBet/BetKing)"
+}
+
+// Keywords are used for pre-filtering.
+func (s scanner) Keywords() []string {
+    return []string{
+        "paystack", "flutterwave", "remita", "interswitch", "sportybet", "betking",
+        "sk_live", "sk_test", "FLWSECK", "macKey",
+    }
+}
+
+// FromData will be called when keywords are matched.
+func (s scanner) FromData(ctx context.Context, verify bool, data []byte) (results []detectors.Result, err error) {
+    dataStr := string(data)
+
+    patterns := map[string]string{
+        "Paystack Secret Key":     `sk_(live|test)_[0-9a-zA-Z]{50,}`,
+        "Flutterwave Secret Key":  `FLWSECK[_-]?[a-zA-Z0-9]{30,}`,
+        "Flutterwave Test Key":    `FLWSECK_TEST-[a-z0-9]{30,}`,
+        "Remita Merchant+Hash":    `[0-9]{10,15}\|?[0-9a-zA-Z]{40,}`,
+        "Interswitch MAC Key":     `macKey["']?\s*[:=]\s*["']?[0-9A-Fa-f]{64}`,
+        "Betting Admin Token":     `eyJ[A-Za-z0-9-_]{100,}|Bearer [A-Za-z0-9-_]{50,}\.[A-Za-z0-9-_]{50,}\.[A-Za-z0-9-_]{50,}`,
+    }
+
+    for name, regexStr := range patterns {
+        rx := regexp.MustCompile(regexStr)
+        matches := rx.FindAllString(dataStr, -1)
+
+        for _, match := range matches {
+            result := detectors.Result{
+                DetectorType: detectorspb.DetectorType_CustomRegex,
+                Verified:     false, // we can't verify without API call
+                ExtraData: map[string]string{
+                    "service": name,
+                },
+            }
+            result.Raw = []byte(match)
+
+            if verify {
+                // Skip verification for now (too many services)
+                result.Verified = false
+            }
+            results = append(results, result)
+        }
+    }
+
+    return results, nil
+}
+
+// New returns a new detector instance.
+func New() detectors.Detector {
+    return &scanner{}
+}