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authorrsiddharth <s@ricketyspace.net>2020-08-29 13:30:47 -0400
committerrsiddharth <s@ricketyspace.net>2020-08-29 13:30:47 -0400
commit9db1426878ff5b81f66d6d73bf69555eb8e5b5d2 (patch)
treed57e6cff053740fe21b74bfdc36d5bcea4908144
parentbd75e7268a8f5532f8348fcd82552ca8d38e7679 (diff)
challenge: do challenge 2
* challenge/c02.go: Challenge 2 snafu. * cryptopals.go: Add challenge 2. * enc/hex.go (DecToHexChar): New function. * enc/xor.go (FixedXOR): New function.
-rw-r--r--challenge/c02.go14
-rw-r--r--cryptopals.go2
-rw-r--r--enc/hex.go10
-rw-r--r--enc/xor.go19
4 files changed, 45 insertions, 0 deletions
diff --git a/challenge/c02.go b/challenge/c02.go
new file mode 100644
index 0000000..deab152
--- /dev/null
+++ b/challenge/c02.go
@@ -0,0 +1,14 @@
+package challenge
+
+import (
+ "fmt"
+ "ricketyspace.net/cryptopals/enc"
+)
+
+func C2() {
+ a := "1c0111001f010100061a024b53535009181c"
+ b := "686974207468652062756c6c277320657965"
+ c := enc.FixedXOR(a, b)
+
+ fmt.Printf("XOR(%v ^ %v) = %v\n", a, b, c)
+}
diff --git a/cryptopals.go b/cryptopals.go
index 9c1c803..37580be 100644
--- a/cryptopals.go
+++ b/cryptopals.go
@@ -20,5 +20,7 @@ func main() {
flag.PrintDefaults()
case 1:
challenge.C1()
+ case 2:
+ challenge.C2()
}
}
diff --git a/enc/hex.go b/enc/hex.go
index 0d19538..a1b9b46 100644
--- a/enc/hex.go
+++ b/enc/hex.go
@@ -14,3 +14,13 @@ func HexCharToDec(c byte) uint16 {
}
return 0
}
+
+func DecToHexChar(i uint16) byte {
+ switch {
+ case 0 <= i && i <= 9:
+ return byte(48 + i)
+ case 10 <= i && i <= 15:
+ return byte(97 + (i - 10))
+ }
+ return 0
+}
diff --git a/enc/xor.go b/enc/xor.go
new file mode 100644
index 0000000..423c0a2
--- /dev/null
+++ b/enc/xor.go
@@ -0,0 +1,19 @@
+package enc
+
+func FixedXOR(a, b string) string {
+ cs := ""
+ if len(a) != len(b) {
+ return cs
+ }
+
+ ab := []byte(a)
+ bb := []byte(b)
+ for i := 0; i < len(ab); i++ {
+ p := HexCharToDec(ab[i])
+ q := HexCharToDec(bb[i])
+ r := DecToHexChar(p ^ q)
+
+ cs += string(r)
+ }
+ return cs
+}