diff options
Diffstat (limited to 'challenge')
| -rw-r--r-- | challenge/c31.go | 172 |
1 files changed, 172 insertions, 0 deletions
diff --git a/challenge/c31.go b/challenge/c31.go new file mode 100644 index 0000000..d97fe11 --- /dev/null +++ b/challenge/c31.go @@ -0,0 +1,172 @@ +// Copyright © 2021 rsiddharth <s@ricketyspace.net> +// SPDX-License-Identifier: ISC + +package challenge + +import ( + "fmt" + "net/http" + "net/url" + "time" + + "ricketyspace.net/cryptopals/lib" +) + +func C31(serve bool) { + // In-Secure Byte Compare. + insecureCompare := func(a, b []byte) bool { + for i := 0; i < len(a); i++ { + if len(b) <= i { + return false + } + if a[i] != b[i] { + return false + } + lib.Sleep(50000000) // Sleep 50ms + } + return true + } + + // HMAC HTTP Server. + httpServer := func() { + // Secret for HMAC + sec := lib.StrToBytes("Rae Street") + + // Signature checkker. + sigCheck := func(f, s string) bool { + // Check signature. + h := lib.HmacSha1(sec, lib.StrToBytes(f)) + + if insecureCompare(h, lib.HexStrToBytes(s)) { + return true + } + return false + } + + // HTTP Handler. + http.HandleFunc("/test", func(w http.ResponseWriter, r *http.Request) { + // Read query. + var f, s []string + var ok bool + q := r.URL.Query() + if f, ok = q["file"]; !ok { + w.WriteHeader(400) + fmt.Fprintf(w, "file not specified\n") + return + } + if len(f) > 1 { + w.WriteHeader(400) + fmt.Fprintf(w, "Cannot specify more than one file\n") + return + } + if s, ok = q["signature"]; !ok { + w.WriteHeader(400) + fmt.Fprintf(w, "signature not specified\n") + return + } + if len(s) > 1 { + w.WriteHeader(400) + fmt.Fprintf(w, + "Cannot specify more than one signature\n") + return + } + if !sigCheck(f[0], s[0]) { + w.WriteHeader(500) // Signature check failed. + } + }) + + // Start HTTP Server + http.ListenAndServe(":9000", nil) + } + + // Makes HTTP POST request to the server. + makeRequest := func(f, s string) int { + // Make HTTP request. + q := fmt.Sprintf("file=%s&signature=%s", f, s) + u, err := url.Parse("http://localhost:9000/test?" + q) + if err != nil { + fmt.Printf("url parse failed: %v\n", err) + return 0 + } + res, err := http.Post(u.String(), "text/plain", nil) + if err != nil { + fmt.Printf("http post failed: %v\n", err) + return res.StatusCode + } + return res.StatusCode + } + + // Crack signature for file "foo". + crack := func() { + stc := time.Now() // Start time of crack + + f := "foo" // File + s := make([]byte, 20) // Signature + + i := 0 + g := byte(0) // Guess byte. + tl := int64(50) // Time limit. + tries := 0 + for { + st := time.Now() + sc := makeRequest(f, lib.BytesToHexStr(s)) + et := time.Now().Sub(st) // Elapsed time. + + if sc == 200 { + fmt.Printf("Signature Cracked: %x"+ + " [tot. elapsed time: %v]\n", + s, time.Now().Sub(stc)) + break + } + if et.Milliseconds() >= tl { + if tries < 5 { // Try guess at least 5 times. + tries += 1 + continue + } + fmt.Printf("Signature Cracked Status: %x"+ + " [tot. elapsed time: %v]\n", + s, time.Now().Sub(stc)) + tl = et.Milliseconds() + 50 + g = 0 + i += 1 + tries = 0 + } else { + g += 1 // Change guess. + s[i] = g // Set guess. + } + } + } + + if serve { + httpServer() + } else { + crack() + } +} + +// Output: +// +// # Server: +// $ ./cryptopals -c 31 -s +// # Client: +// $ ./cryptopals -c 31 +// Signature Cracked Status: 4400000000000000000000000000000000000000 [tot. elapsed time: 370.025362ms] +// Signature Cracked Status: 44ee000000000000000000000000000000000000 [tot. elapsed time: 15.370118297s] +// Signature Cracked Status: 44ee570000000000000000000000000000000000 [tot. elapsed time: 26.920301887s] +// Signature Cracked Status: 44ee574500000000000000000000000000000000 [tot. elapsed time: 40.79052969s] +// Signature Cracked Status: 44ee5745d3000000000000000000000000000000 [tot. elapsed time: 1m33.240732048s] +// Signature Cracked Status: 44ee5745d3240000000000000000000000000000 [tot. elapsed time: 1m46.200916778s] +// Signature Cracked Status: 44ee5745d324fd00000000000000000000000000 [tot. elapsed time: 3m20.301607262s] +// Signature Cracked Status: 44ee5745d324fda7000000000000000000000000 [tot. elapsed time: 4m33.312205527s] +// Signature Cracked Status: 44ee5745d324fda71e0000000000000000000000 [tot. elapsed time: 4m50.952330999s] +// Signature Cracked Status: 44ee5745d324fda71ec000000000000000000000 [tot. elapsed time: 6m38.743155826s] +// Signature Cracked Status: 44ee5745d324fda71ec0cb000000000000000000 [tot. elapsed time: 8m45.094213819s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd0000000000000000 [tot. elapsed time: 11m15.26538765s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e00000000000000 [tot. elapsed time: 12m51.226137697s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e0c000000000000 [tot. elapsed time: 13m5.626232024s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e0c620000000000 [tot. elapsed time: 14m33.976999266s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e0c621c00000000 [tot. elapsed time: 15m4.937197749s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e0c621c70000000 [tot. elapsed time: 16m58.588103335s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e0c621c70ba0000 [tot. elapsed time: 20m15.459696698s] +// Signature Cracked Status: 44ee5745d324fda71ec0cbdd7e0c621c70bae700 [tot. elapsed time: 24m33.111719984s] +// Signature Cracked: 44ee5745d324fda71ec0cbdd7e0c621c70bae785 [tot. elapsed time: 27m7.782947967s] |