diff options
Diffstat (limited to 'challenge/c14.go')
| -rw-r--r-- | challenge/c14.go | 31 |
1 files changed, 24 insertions, 7 deletions
diff --git a/challenge/c14.go b/challenge/c14.go index 552c2df..b35f2cd 100644 --- a/challenge/c14.go +++ b/challenge/c14.go @@ -11,6 +11,23 @@ import ( func C14() { sheep := byte(65) + unknown := `Um9sbGluJyBpbiBteSA1LjAKV2l0aCBteSByYWctdG9wIGRvd24gc28gbXkg +aGFpciBjYW4gYmxvdwpUaGUgZ2lybGllcyBvbiBzdGFuZGJ5IHdhdmluZyBq +dXN0IHRvIHNheSBoaQpEaWQgeW91IHN0b3A/IE5vLCBJIGp1c3QgZHJvdmUg +YnkK` + key, err := lib.RandomBytes(16) + if err != nil { + fmt.Printf("key generatation error: %v", err) + } + oracleRandom, err := lib.RandomBytes(int(lib.RandomInt(1, 4096))) + if err != nil { + fmt.Printf("oracle random generation error: %v", err) + } + encrypt := func(in []byte) []byte { + in = append(oracleRandom, in...) + in = append(in, lib.Base64ToBytes(unknown)...) + return lib.AESEncryptECB(in, key) + } freshSheepBytes := func(n int) []byte { in := make([]byte, n) for i := 0; i < n; i++ { @@ -22,11 +39,11 @@ func C14() { in := make([]byte, 0) in = append(in, sheep) - is := len(lib.OracleAESVarEncryptECB(in)) // initial size + is := len(encrypt(in)) // initial size bs := 0 for { in = append(in, sheep) - bs = len(lib.OracleAESVarEncryptECB(in)) + bs = len(encrypt(in)) if bs != is { return (bs - is) } @@ -41,7 +58,7 @@ func C14() { found := false for { in := append(v, tsb...) - c := lib.OracleAESVarEncryptECB(in) + c := encrypt(in) index, found = lib.HasConsecutiveMatchingBlocks(c, blocksize) if found { break @@ -63,7 +80,7 @@ func C14() { findUnknownStringNumBlocksLength := func(rpl, blocksize int) (int, int) { padding := blocksize - (rpl % blocksize) in := make([]byte, padding) - c_sz := len(lib.OracleAESVarEncryptECB(in)) // Cipher size + c_sz := len(encrypt(in)) // Cipher size nblocks := c_sz / blocksize // total number of blocks rblocks := (rpl + padding) / blocksize // number of blocks of random prefix @@ -71,7 +88,7 @@ func C14() { // Figure out size of unknown string. for { in = append(in, sheep) - bs := len(lib.OracleAESVarEncryptECB(in)) + bs := len(encrypt(in)) if bs != c_sz { return ublocks, (c_sz - len(in) - rpl) } @@ -85,7 +102,7 @@ func C14() { // `in` (n-1)th block that is known // `ds` deciphered unknown string decipherOneByte := func(nrpb, rpo, blocksize, block, n int, in, ds []byte) ([]byte, []byte) { - oo := lib.OracleAESVarEncryptECB(in[0:(len(in) - n)]) + oo := encrypt(in[0:(len(in) - n)]) s := (nrpb * blocksize) + 16*(block-1) e := s + 16 @@ -99,7 +116,7 @@ func C14() { // Try all combinations. for i := 0; i < 256; i++ { in[len(in)-1] = byte(i) - oo = lib.OracleAESVarEncryptECB(in) + oo = encrypt(in) if lib.BlocksEqual(nbl, oo[(nrpb*blocksize):(nrpb*blocksize)+16]) { |