forked from External/grumble
cryptstate: s/AESBlockSize/aes.BlockSize, rename to grumble/cryptstate.
This commit is contained in:
Mikkel Krautz
parent
6295adad98
commit
e15ce28618
6 changed files with 73 additions and 72 deletions
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@ -12,13 +12,12 @@ import (
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"time"
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)
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const AESBlockSize = 16
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const DecryptHistorySize = 0x100
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type CryptState struct {
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RawKey [AESBlockSize]byte
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EncryptIV [AESBlockSize]byte
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DecryptIV [AESBlockSize]byte
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RawKey [aes.BlockSize]byte
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EncryptIV [aes.BlockSize]byte
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DecryptIV [aes.BlockSize]byte
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decryptHistory [DecryptHistorySize]byte
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LastGoodTime int64
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@ -55,17 +54,17 @@ func (cs *CryptState) GenerateKey() (err os.Error) {
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}
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func (cs *CryptState) SetKey(key []byte, eiv []byte, div []byte) (err os.Error) {
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if copy(cs.RawKey[0:], key[0:]) != AESBlockSize {
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if copy(cs.RawKey[0:], key[0:]) != aes.BlockSize {
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err = os.NewError("Unable to copy key")
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return
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}
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if copy(cs.EncryptIV[0:], eiv[0:]) != AESBlockSize {
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if copy(cs.EncryptIV[0:], eiv[0:]) != aes.BlockSize {
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err = os.NewError("Unable to copy EIV")
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return
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}
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if copy(cs.DecryptIV[0:], div[0:]) != AESBlockSize {
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if copy(cs.DecryptIV[0:], div[0:]) != aes.BlockSize {
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err = os.NewError("Unable to copy DIV")
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return
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}
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@ -90,8 +89,8 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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return
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}
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var saveiv [AESBlockSize]byte
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var tag [AESBlockSize]byte
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var saveiv [aes.BlockSize]byte
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var tag [aes.BlockSize]byte
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var ivbyte byte
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var restore bool
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lost := 0
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@ -100,7 +99,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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ivbyte = src[0]
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restore = false
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if copy(saveiv[0:], cs.DecryptIV[0:]) != AESBlockSize {
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if copy(saveiv[0:], cs.DecryptIV[0:]) != aes.BlockSize {
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err = os.NewError("Copy failed")
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return
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}
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@ -111,7 +110,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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cs.DecryptIV[0] = ivbyte
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} else if ivbyte < cs.DecryptIV[0] {
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cs.DecryptIV[0] = ivbyte
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for i := 1; i < AESBlockSize; i++ {
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for i := 1; i < aes.BlockSize; i++ {
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cs.DecryptIV[i] += 1
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if cs.DecryptIV[i] > 0 {
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break
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@ -141,7 +140,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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late = 1
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lost = -1
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cs.DecryptIV[0] = ivbyte
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for i := 1; i < AESBlockSize; i++ {
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for i := 1; i < aes.BlockSize; i++ {
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cs.DecryptIV[i] -= 1
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if cs.DecryptIV[i] > 0 {
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break
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@ -156,7 +155,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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// Lost a few packets, and wrapped around
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lost = int(256 - int(cs.DecryptIV[0]) + int(ivbyte) - 1)
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cs.DecryptIV[0] = ivbyte
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for i := 1; i < AESBlockSize; i++ {
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for i := 1; i < aes.BlockSize; i++ {
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cs.DecryptIV[i] += 1
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if cs.DecryptIV[i] > 0 {
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break
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@ -168,8 +167,8 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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}
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if cs.decryptHistory[cs.DecryptIV[0]] == cs.DecryptIV[0] {
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if copy(cs.DecryptIV[0:], saveiv[0:]) != AESBlockSize {
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err = os.NewError("Failed to copy AESBlockSize bytes")
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if copy(cs.DecryptIV[0:], saveiv[0:]) != aes.BlockSize {
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err = os.NewError("Failed to copy aes.BlockSize bytes")
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return
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}
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}
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@ -179,7 +178,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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for i := 0; i < 3; i++ {
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if tag[i] != src[i+1] {
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if copy(cs.DecryptIV[0:], saveiv[0:]) != AESBlockSize {
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if copy(cs.DecryptIV[0:], saveiv[0:]) != aes.BlockSize {
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err = os.NewError("Error while trying to recover from error")
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return
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}
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@ -191,7 +190,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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cs.decryptHistory[cs.DecryptIV[0]] = cs.DecryptIV[0]
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if restore {
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if copy(cs.DecryptIV[0:], saveiv[0:]) != AESBlockSize {
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if copy(cs.DecryptIV[0:], saveiv[0:]) != aes.BlockSize {
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err = os.NewError("Error while trying to recover IV")
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return
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}
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@ -215,7 +214,7 @@ func (cs *CryptState) Decrypt(dst, src []byte) (err os.Error) {
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}
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func (cs *CryptState) Encrypt(dst, src []byte) {
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var tag [AESBlockSize]byte
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var tag [aes.BlockSize]byte
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// First, increase our IV
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for i := range cs.EncryptIV {
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@ -242,53 +241,53 @@ func zeros(block []byte) {
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}
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func xor(dst []byte, a []byte, b []byte) {
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for i := 0; i < AESBlockSize; i++ {
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for i := 0; i < aes.BlockSize; i++ {
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dst[i] = a[i] ^ b[i]
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}
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}
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func times2(block []byte) {
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carry := (block[0] >> 7) & 0x1
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for i := 0; i < AESBlockSize-1; i++ {
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for i := 0; i < aes.BlockSize-1; i++ {
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block[i] = (block[i] << 1) | ((block[i+1] >> 7) & 0x1)
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}
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block[AESBlockSize-1] = (block[AESBlockSize-1] << 1) ^ (carry * 135)
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block[aes.BlockSize-1] = (block[aes.BlockSize-1] << 1) ^ (carry * 135)
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}
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func times3(block []byte) {
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carry := (block[0] >> 7) & 0x1
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for i := 0; i < AESBlockSize-1; i++ {
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for i := 0; i < aes.BlockSize-1; i++ {
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block[i] ^= (block[i] << 1) | ((block[i+1] >> 7) & 0x1)
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}
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block[AESBlockSize-1] ^= ((block[AESBlockSize-1] << 1) ^ (carry * 135))
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block[aes.BlockSize-1] ^= ((block[aes.BlockSize-1] << 1) ^ (carry * 135))
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}
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func (cs *CryptState) OCBEncrypt(dst []byte, src []byte, nonce []byte, tag []byte) (err os.Error) {
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var delta [AESBlockSize]byte
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var checksum [AESBlockSize]byte
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var tmp [AESBlockSize]byte
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var pad [AESBlockSize]byte
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var delta [aes.BlockSize]byte
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var checksum [aes.BlockSize]byte
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var tmp [aes.BlockSize]byte
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var pad [aes.BlockSize]byte
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off := 0
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cs.cipher.Encrypt(delta[0:], cs.EncryptIV[0:])
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zeros(checksum[0:])
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remain := len(src)
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for remain > AESBlockSize {
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for remain > aes.BlockSize {
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times2(delta[0:])
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xor(tmp[0:], delta[0:], src[off:off+AESBlockSize])
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xor(tmp[0:], delta[0:], src[off:off+aes.BlockSize])
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cs.cipher.Encrypt(tmp[0:], tmp[0:])
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xor(dst[off:off+AESBlockSize], delta[0:], tmp[0:])
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xor(checksum[0:], checksum[0:], src[off:off+AESBlockSize])
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remain -= AESBlockSize
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off += AESBlockSize
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xor(dst[off:off+aes.BlockSize], delta[0:], tmp[0:])
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xor(checksum[0:], checksum[0:], src[off:off+aes.BlockSize])
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remain -= aes.BlockSize
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off += aes.BlockSize
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}
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times2(delta[0:])
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zeros(tmp[0:])
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num := remain * 8
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tmp[AESBlockSize-2] = uint8((uint32(num) >> 8) & 0xff)
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tmp[AESBlockSize-1] = uint8(num & 0xff)
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tmp[aes.BlockSize-2] = uint8((uint32(num) >> 8) & 0xff)
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tmp[aes.BlockSize-1] = uint8(num & 0xff)
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xor(tmp[0:], tmp[0:], delta[0:])
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cs.cipher.Encrypt(pad[0:], tmp[0:])
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copied := copy(tmp[0:], src[off:])
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@ -296,7 +295,7 @@ func (cs *CryptState) OCBEncrypt(dst []byte, src []byte, nonce []byte, tag []byt
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err = os.NewError("Copy failed")
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return
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}
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if copy(tmp[copied:], pad[copied:]) != (AESBlockSize - remain) {
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if copy(tmp[copied:], pad[copied:]) != (aes.BlockSize - remain) {
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err = os.NewError("Copy failed")
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return
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}
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@ -315,31 +314,31 @@ func (cs *CryptState) OCBEncrypt(dst []byte, src []byte, nonce []byte, tag []byt
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}
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func (cs *CryptState) OCBDecrypt(plain []byte, encrypted []byte, nonce []byte, tag []byte) (err os.Error) {
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var checksum [AESBlockSize]byte
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var delta [AESBlockSize]byte
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var tmp [AESBlockSize]byte
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var pad [AESBlockSize]byte
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var checksum [aes.BlockSize]byte
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var delta [aes.BlockSize]byte
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var tmp [aes.BlockSize]byte
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var pad [aes.BlockSize]byte
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off := 0
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cs.cipher.Encrypt(delta[0:], nonce[0:])
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zeros(checksum[0:])
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remain := len(encrypted)
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for remain > AESBlockSize {
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for remain > aes.BlockSize {
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times2(delta[0:])
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xor(tmp[0:], delta[0:], encrypted[off:off+AESBlockSize])
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xor(tmp[0:], delta[0:], encrypted[off:off+aes.BlockSize])
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cs.cipher.Decrypt(tmp[0:], tmp[0:])
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xor(plain[off:off+AESBlockSize], delta[0:], tmp[0:])
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xor(checksum[0:], checksum[0:], plain[off:off+AESBlockSize])
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off += AESBlockSize
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remain -= AESBlockSize
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xor(plain[off:off+aes.BlockSize], delta[0:], tmp[0:])
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xor(checksum[0:], checksum[0:], plain[off:off+aes.BlockSize])
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off += aes.BlockSize
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remain -= aes.BlockSize
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}
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times2(delta[0:])
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zeros(tmp[0:])
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num := remain * 8
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tmp[AESBlockSize-2] = uint8((uint32(num) >> 8) & 0xff)
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tmp[AESBlockSize-1] = uint8(num & 0xff)
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tmp[aes.BlockSize-2] = uint8((uint32(num) >> 8) & 0xff)
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tmp[aes.BlockSize-1] = uint8(num & 0xff)
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xor(tmp[0:], tmp[0:], delta[0:])
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cs.cipher.Encrypt(pad[0:], tmp[0:])
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zeros(tmp[0:])
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