diff --git a/src/common/crypto.c b/src/common/crypto.c
index eaf438e835..66a666e943 100644
--- a/src/common/crypto.c
+++ b/src/common/crypto.c
@@ -974,12 +974,11 @@ int
 crypto_pk_check_fingerprint_syntax(const char *s)
 {
   int i;
-  const unsigned char *cp = s;
   for (i = 0; i < FINGERPRINT_LEN; ++i) {
     if ((i%5) == 4) {
-      if (!TOR_ISSPACE(cp[i])) return 0;
+      if (!TOR_ISSPACE(s[i])) return 0;
     } else {
-      if (!TOR_ISXDIGIT(cp[i])) return 0;
+      if (!TOR_ISXDIGIT(s[i])) return 0;
     }
   }
   if (s[FINGERPRINT_LEN]) return 0;