diff options
| -rw-r--r-- | challenge/c12.go | 157 | ||||
| -rw-r--r-- | challenge/c14.go | 11 |
2 files changed, 87 insertions, 81 deletions
diff --git a/challenge/c12.go b/challenge/c12.go index a19777b..b76f28a 100644 --- a/challenge/c12.go +++ b/challenge/c12.go @@ -5,16 +5,89 @@ package challenge import ( "fmt" + "ricketyspace.net/cryptopals/lib" ) -var sheep byte = 65 - func C12() { + sheep := byte(65) + freshSheepBytes := func(n int) []byte { + in := make([]byte, n) + for i := 0; i < n; i++ { + in[i] = sheep + } + return in + } + findBlockSize := func() int { + in := make([]byte, 0) + + in = append(in, sheep) + is := len(lib.OracleAESEncryptECB(in)) // initial size + bs := 0 // block size + for { + in = append(in, sheep) + bs = len(lib.OracleAESEncryptECB(in)) + if bs != is { + return (bs - is) + } + } + } + findUnknownStringCharacteristics := func(blocksize int) (int, int) { + in := make([]byte, 0) + c_sz := len(lib.OracleAESEncryptECB(in)) // Cipher size + nblocks := c_sz / blocksize // number of blocks + + // Figure out ize of unknown string. + for { + in = append(in, sheep) + bs := len(lib.OracleAESEncryptECB(in)) + if bs != c_sz { + return nblocks, (c_sz - len(in)) + } + } + + } + isOracleUsingECB := func() bool { + in := lib.StrToBytes("OliverMkTukudzi OliverMkTukudzi OliverMkTukudzi") + oo := lib.OracleAESEncryptECB(in) + if lib.CipherUsesECB(oo) != nil { + return true + } + return false + } + // `blocksize` is the size of a block + // `block` is the nth block that is being deciphered + // `n` is the nth byte of the block `block` that is going to be deciphered. + // `in` (n-1)th block that is known + // `ds` deciphered unknown string + decipherUnknownStringIter := func(blocksize, block, n int, in, ds []byte) ([]byte, []byte) { + oo := lib.OracleAESEncryptECB(in[0:(blocksize - n)]) + + s := 16 * (block - 1) + e := s + 16 + nbl := oo[s:e] // nth block of the cipher + + // Shift `in` to the left by one place. + for i := 0; i < blocksize-1; i++ { + in[i] = in[i+1] + } + + // Try all combinations. + for i := 0; i < 256; i++ { + in[15] = byte(i) + oo = lib.OracleAESEncryptECB(in) + + if lib.BlocksEqual(nbl, oo[0:16]) { + ds = append(ds, in[15]) + return in, ds + } + } + panic("not found!") + } + if !isOracleUsingECB() { panic("oracle not using ecb mode") } - blocksize := findBlockSize() nbl, us_sz := findUnknownStringCharacteristics(blocksize) in := freshSheepBytes(blocksize) @@ -35,84 +108,6 @@ func C12() { fmt.Printf("Unknown String:\n%v", lib.BytesToStr(ds)) } -func freshSheepBytes(n int) []byte { - in := make([]byte, n) - for i := 0; i < n; i++ { - in[i] = sheep - } - return in -} - -func findBlockSize() int { - in := make([]byte, 0) - - in = append(in, sheep) - is := len(lib.OracleAESEncryptECB(in)) // initial size - bs := 0 // block size - for { - in = append(in, sheep) - bs = len(lib.OracleAESEncryptECB(in)) - if bs != is { - return (bs - is) - } - } -} - -func findUnknownStringCharacteristics(blocksize int) (int, int) { - in := make([]byte, 0) - c_sz := len(lib.OracleAESEncryptECB(in)) // Cipher size - nblocks := c_sz / blocksize // number of blocks - - // Figure out ize of unknown string. - for { - in = append(in, sheep) - bs := len(lib.OracleAESEncryptECB(in)) - if bs != c_sz { - return nblocks, (c_sz - len(in)) - } - } - -} - -func isOracleUsingECB() bool { - in := lib.StrToBytes("OliverMkTukudzi OliverMkTukudzi OliverMkTukudzi") - oo := lib.OracleAESEncryptECB(in) - if lib.CipherUsesECB(oo) != nil { - return true - } - return false -} - -// `blocksize` is the size of a block -// `block` is the nth block that is being deciphered -// `n` is the nth byte of the block `block` that is going to be deciphered. -// `in` (n-1)th block that is known -// `ds` deciphered unknown string -func decipherUnknownStringIter(blocksize, block, n int, in, ds []byte) ([]byte, []byte) { - oo := lib.OracleAESEncryptECB(in[0:(blocksize - n)]) - - s := 16 * (block - 1) - e := s + 16 - nbl := oo[s:e] // nth block of the cipher - - // Shift `in` to the left by one place. - for i := 0; i < blocksize-1; i++ { - in[i] = in[i+1] - } - - // Try all combinations. - for i := 0; i < 256; i++ { - in[15] = byte(i) - oo = lib.OracleAESEncryptECB(in) - - if lib.BlocksEqual(nbl, oo[0:16]) { - ds = append(ds, in[15]) - return in, ds - } - } - panic("not found!") -} - // Output: // Unknown String: // Rollin' in my 5.0 diff --git a/challenge/c14.go b/challenge/c14.go index 3b5b11c..4471f44 100644 --- a/challenge/c14.go +++ b/challenge/c14.go @@ -5,9 +5,12 @@ package challenge import ( "fmt" + "ricketyspace.net/cryptopals/lib" ) +var sheep byte = 65 + func C14() { blocksize := findBlockSizeForVarEncryptECB() rpl, nrpb, rpo := findRandPrefixLen(blocksize) @@ -32,6 +35,14 @@ func C14() { fmt.Printf("Unknown String:\n%v", lib.BytesToStr(ds)) } +func freshSheepBytes(n int) []byte { + in := make([]byte, n) + for i := 0; i < n; i++ { + in[i] = sheep + } + return in +} + func findBlockSizeForVarEncryptECB() int { in := make([]byte, 0) |