$chacha20$ (all lower case) per @magnumripper

src/interface.c

@@ -384,7 +384,7 @@ static const char SIGNATURE_FORTIGATE[]        = "AK1";
 static const char SIGNATURE_ATLASSIAN[]        = "{PKCS5S2}";
 static const char SIGNATURE_NETBSD_SHA1CRYPT[] = "$sha1$";
 static const char SIGNATURE_BLAKE2B[]          = "$BLAKE2$";
-static const char SIGNATURE_CHACHA20[]         = "$ChaCha20$";
+static const char SIGNATURE_CHACHA20[]         = "$chacha20$";
 static const char SIGNATURE_ETHEREUM_PBKDF2[]  = "$ethereum$p";
 static const char SIGNATURE_ETHEREUM_SCRYPT[]  = "$ethereum$s";
 

tools/test.pl

@@ -8584,7 +8584,7 @@ END_CODE
     my $enc_offset = substr($enc, $offset, 8);
     $hash_buf = $enc_offset;
 
-    $tmp_hash = sprintf ("\$ChaCha20\$\*%s\*%d\*%s\*%s\*%s", $counter, $offset, $iv, unpack("H*", substr($plaintext, $offset, 8)), unpack("H*", $enc_offset));
+    $tmp_hash = sprintf ("\$chacha20\$\*%s\*%d\*%s\*%s\*%s", $counter, $offset, $iv, unpack("H*", substr($plaintext, $offset, 8)), unpack("H*", $enc_offset));
   }
   elsif ($mode == 15600)
   {