challenge: do challenge 5

* challenge/c05.go: Implement challenge 5.
* cryptopals.go (main): Add handling to run challenge 5.
* lib/hex.go (BytesToHexStr): New function.
* lib/xor.go (RepeatingXOR): New function.

1 files changed, 12 insertions, 0 deletions

diff --git a/lib/hex.go b/lib/hex.go
index 6fe7e6a..5b1741f 100644
--- a/lib/hex.go
+++ b/lib/hex.go
@@ -53,3 +53,15 @@ func ByteToHexStr(b byte) string {
 
 	return s
 }
+
+func BytesToHexStr(bs []byte) string {
+	hs := ""
+	if len(bs) < 1 {
+		return hs
+	}
+
+	for i := 0; i < len(bs); i++ {
+		hs += ByteToHexStr(bs[i])
+	}
+	return hs
+}