lib: remove oracle.go

Move functions into C12 and C14 where they're used.

3 files changed, 45 insertions, 52 deletions

diff --git a/challenge/c12.go b/challenge/c12.go
index b76f28a..0308bd4 100644
--- a/challenge/c12.go
+++ b/challenge/c12.go
@@ -11,6 +11,18 @@ import (
 
 func C12() {
 	sheep := byte(65)
+	unknown := `Um9sbGluJyBpbiBteSA1LjAKV2l0aCBteSByYWctdG9wIGRvd24gc28gbXkg
+aGFpciBjYW4gYmxvdwpUaGUgZ2lybGllcyBvbiBzdGFuZGJ5IHdhdmluZyBq
+dXN0IHRvIHNheSBoaQpEaWQgeW91IHN0b3A/IE5vLCBJIGp1c3QgZHJvdmUg
+YnkK`
+	key, err := lib.RandomBytes(16)
+	if err != nil {
+		fmt.Printf("key generatation error: %v", err)
+	}
+	encrypt := func(in []byte) []byte {
+		return lib.AESEncryptECB(append(in, lib.Base64ToBytes(unknown)...), key)
+	}
+
 	freshSheepBytes := func(n int) []byte {
 		in := make([]byte, n)
 		for i := 0; i < n; i++ {
@@ -22,11 +34,11 @@ func C12() {
 		in := make([]byte, 0)
 
 		in = append(in, sheep)
-		is := len(lib.OracleAESEncryptECB(in)) // initial size
-		bs := 0                                // block size
+		is := len(encrypt(in)) // initial size
+		bs := 0                // block size
 		for {
 			in = append(in, sheep)
-			bs = len(lib.OracleAESEncryptECB(in))
+			bs = len(encrypt(in))
 			if bs != is {
 				return (bs - is)
 			}
@@ -34,13 +46,13 @@ func C12() {
 	}
 	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
+		c_sz := len(encrypt(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))
+			bs := len(encrypt(in))
 			if bs != c_sz {
 				return nblocks, (c_sz - len(in))
 			}
@@ -49,7 +61,7 @@ func C12() {
 	}
 	isOracleUsingECB := func() bool {
 		in := lib.StrToBytes("OliverMkTukudzi OliverMkTukudzi OliverMkTukudzi")
-		oo := lib.OracleAESEncryptECB(in)
+		oo := encrypt(in)
 		if lib.CipherUsesECB(oo) != nil {
 			return true
 		}
@@ -61,7 +73,7 @@ func C12() {
 	// `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)])
+		oo := encrypt(in[0:(blocksize - n)])
 
 		s := 16 * (block - 1)
 		e := s + 16
@@ -75,7 +87,7 @@ func C12() {
 		// Try all combinations.
 		for i := 0; i < 256; i++ {
 			in[15] = byte(i)
-			oo = lib.OracleAESEncryptECB(in)
+			oo = encrypt(in)
 
 			if lib.BlocksEqual(nbl, oo[0:16]) {
 				ds = append(ds, in[15])
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]) {
diff --git a/lib/oracle.go b/lib/oracle.go
deleted file mode 100644
index 8a449a1..0000000
--- a/lib/oracle.go
+++ /dev/null
@@ -1,36 +0,0 @@
-// Copyright © 2020 rsiddharth <s@ricketyspace.net>
-// SPDX-License-Identifier: ISC
-
-package lib
-
-var oracleUnknown string = `Um9sbGluJyBpbiBteSA1LjAKV2l0aCBteSByYWctdG9wIGRvd24gc28gbXkg
-aGFpciBjYW4gYmxvdwpUaGUgZ2lybGllcyBvbiBzdGFuZGJ5IHdhdmluZyBq
-dXN0IHRvIHNheSBoaQpEaWQgeW91IHN0b3A/IE5vLCBJIGp1c3QgZHJvdmUg
-YnkK`
-
-var oracleKey []byte
-var oracleRandom []byte
-
-func init() {
-	var err error
-
-	oracleKey, err = RandomBytes(16)
-	if err != nil {
-		panic(err)
-	}
-
-	oracleRandom, err = RandomBytes(int(RandomInt(1, 4096)))
-	if err != nil {
-		panic(err)
-	}
-}
-
-func OracleAESEncryptECB(in []byte) []byte {
-	return AESEncryptECB(append(in, Base64ToBytes(oracleUnknown)...), oracleKey)
-}
-
-func OracleAESVarEncryptECB(in []byte) []byte {
-	in = append(oracleRandom, in...)
-	in = append(in, Base64ToBytes(oracleUnknown)...)
-	return AESEncryptECB(in, oracleKey)
-}