diff options
| -rw-r--r-- | challenge/c08.go | 25 | ||||
| -rw-r--r-- | lib/blocks.go | 23 |
2 files changed, 24 insertions, 24 deletions
diff --git a/challenge/c08.go b/challenge/c08.go index 862c070..1f43b45 100644 --- a/challenge/c08.go +++ b/challenge/c08.go @@ -12,7 +12,7 @@ func C8() { for i := 0; i < len(c08); i++ { bs := lib.HexStrToBytes(c08[i]) - block := isECB(bs) + block := lib.BlockIsECB(bs) if block != nil { fmt.Printf("Cipher at line %d (%s)", i+1, c08[i]) fmt.Printf(" might be AES encrypted in ECB mode.\n") @@ -27,29 +27,6 @@ func C8() { // Cipher at line 133 (d880619740a8a19b7840a8a31c810a3d08649af70dc06f4fd5d2d69c744cd283e2dd052f6b641dbf9d11b0348542bb5708649af70dc06f4fd5d2d69c744cd2839475c9dfdbc1d46597949d9c7e82bf5a08649af70dc06f4fd5d2d69c744cd28397a93eab8d6aecd566489154789a6b0308649af70dc06f4fd5d2d69c744cd283d403180c98c8f6db1f2a3f9c4040deb0ab51b29933f2c123c58386b06fba186a) might be AES encrypted in ECB mode. // 16-byte block '08649af70dc06f4fd5d2d69c744cd283' occurs more than once in this cipher. -func isECB(bs []byte) []byte { - blocks := lib.BreakIntoBlocks(bs, 16) - - for i := 0; i < len(blocks); i++ { - if hasMatchingBlock(i, blocks) { - return blocks[i] - } - } - return nil -} - -func hasMatchingBlock(id int, blocks [][]byte) bool { - for i := 0; i < len(blocks); i++ { - if i == id { - continue - } - if lib.BlocksEqual(blocks[i], blocks[id]) { - return true - } - } - return false -} - var c08 = []string{ "8a10247f90d0a05538888ad6205882196f5f6d05c21ec8dca0cb0be02c3f8b09e382963f443aa514daa501257b09a36bf8c4c392d8ca1bf4395f0d5f2542148c7e5ff22237969874bf66cb85357ef99956accf13ba1af36ca7a91a50533c4d89b7353f908c5a166774293b0bf6247391df69c87dacc4125a99ec417221b58170e633381e3847c6b1c28dda2913c011e13fc4406f8fe73bbf78e803e1d995ce4d", "bd20aad820c9e387ea57408566e5844c1e470e9d6fbbdba3a6b4df1dd85bce2208f1944f1827d015df9c46c22803f41d1052acb721977f0ccc13db95c970252091ea5e36e423ee6a2f2d12ef909fcadd42529885d221af1225e32161b85e6dc03465cf398c937846b18bac05e88820a567caac113762753dffbe6ece09823bab5aee947a682bb3156f42df1d8dc320a897ee79981cf937390b4ae93eb8657f6c", diff --git a/lib/blocks.go b/lib/blocks.go index 1ba811f..452766b 100644 --- a/lib/blocks.go +++ b/lib/blocks.go @@ -61,6 +61,29 @@ func BlocksEqual(a, b []byte) bool { return true } +func BlockIsECB(bs []byte) []byte { + blocks := BreakIntoBlocks(bs, 16) + + for i := 0; i < len(blocks); i++ { + if hasMatchingBlock(i, blocks) { + return blocks[i] + } + } + return nil +} + +func hasMatchingBlock(id int, blocks [][]byte) bool { + for i := 0; i < len(blocks); i++ { + if i == id { + continue + } + if BlocksEqual(blocks[i], blocks[id]) { + return true + } + } + return false +} + // Performs PKCS#7 Padding on the input `in` and block size `k`. // Assumes 0 > `k` < 256 // Reference: https://tools.ietf.org/html/rfc5652#section-6.3 |