func bworker(name string, conn *net.TCPConn) {
debug := utils.NewDebug(utils.USER, name)
defer func() {
debug.Printf("... %s worker finished.", name)
conn.Close()
}()
debug.Printf("%s worker connected to remote address %s", name, conn.RemoteAddr())
// Obtain keys etc.
keyB, e := aeskey.KeyB()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
ivB, e := aeskey.IvB()
if e != nil {
fmt.Printf("AES IV error: %v\n", e)
return
}
debug.PrintBuffer(ivB, "B's IV = ")
//Get input from TCP stream
ibuff := utils.MakeTcpIEncoding(conn)
debug.Printf("Reading nonce N")
nonce, e := ibuff.ReadBinary()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.PrintBuffer(nonce, "Nonce N = ")
debug.Printf("Reading A")
a, e := ibuff.ReadString()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.Printf("A = %v", a)
//if a != "student" {
// fmt.Printf("Incorrect name for A\n")
// return
//}
debug.Printf("Reading B")
b, e := ibuff.ReadString()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.Printf("B = %v", b)
if b != "lecturer" {
fmt.Printf("Incorrect name for B\n")
return
}
debug.Printf("Reading A's Token")
tokenA, e := ibuff.ReadBinary()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.PrintBuffer(tokenA, "Token Ciphertext = ")
// Send output to the server
laddr := "127.0.0.1:8005"
addr, e := net.ResolveTCPAddr("tcp", laddr)
if e != nil {
fmt.Printf("Cannot resolve address %s\n", laddr)
return
}
sconn, e := net.DialTCP("tcp", nil, addr)
if e != nil {
fmt.Printf("Dialed failed on address %s\n", laddr)
return
}
defer func() {
sconn.Close()
}()
sobuff := utils.MakeTcpOEncoding(sconn)
e = sobuff.WriteBinary(nonce)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
e = sobuff.WriteString(a)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
e = sobuff.WriteString(b)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
e = sobuff.WriteBinary(tokenA)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
// Set up & send B's Token
var tokenB ortokens.UserToken
usernonce := make([]byte, 16)
_, _ = rand.Read(usernonce)
tokenB.UserNonce = usernonce[0:]
tokenB.Nonce = nonce[0:]
tokenB.A = a
tokenB.B = b
e = ortokens.WriteUserToken(ivB, keyB, &tokenB, sobuff)
// Read Server Response
sibuff := utils.MakeTcpIEncoding(sconn)
debug.Printf("Reading nonce N")
rnonce, e := sibuff.ReadBinary()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.PrintBuffer(rnonce, "Nonce N = ")
if !bytes.Equal(rnonce, nonce) {
fmt.Printf("Invalid nonce\n")
return
}
debug.Printf("Reading A's Key Token")
keytokenA, e := sibuff.ReadBinary()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.PrintBuffer(keytokenA, "Key Token Ciphertext = ")
keytokenB, e := ortokens.ReadKeyToken(debug, "B", ivB, keyB, sibuff)
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
if !bytes.Equal(keytokenB.UserNonce, tokenB.UserNonce) {
fmt.Printf("Invalid nonce\n")
return
}
// Reply to A
obuff := utils.MakeTcpOEncoding(conn)
e = obuff.WriteBinary(nonce)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
e = obuff.WriteBinary(keytokenA)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
// Get cipphertext message
iv, e := aeskey.Iv()
if e != nil {
fmt.Printf("AES IV error: %v\n", e)
return
}
debug.Printf("Reading protocol message ciphertext")
ciphertext, e := ibuff.ReadBinary()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.PrintBuffer(ciphertext, "Ciphertext = ")
debug.Printf("Decrypting ciphertext")
t, e := utils.Decrypt(ortokens.AMP, iv, keytokenB.Key[0:], ciphertext)
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.PrintBuffer(t, "Plaintext = ")
sbuff := utils.MakeByteIEncoding(t)
debug.Printf("Reading message")
msg, e := sbuff.ReadString()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.Printf("Message = %s", msg)
// Send response
pbuff := utils.MakeByteOEncoding(2048)
// e = pbuff.WriteString(strconv.Itoa(len(msg)))
e = pbuff.WriteInteger(strconv.Itoa(len(msg)))
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
plaintext, e := pbuff.GetBuffer()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
ciphertext, e = utils.Encrypt(ortokens.AMP, iv, keytokenB.Key[0:], plaintext)
if e != nil {
fmt.Printf("Encryption error: %v\n", e)
return
}
e = obuff.WriteBinary(ciphertext)
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
}
func sworker(name string, conn *net.TCPConn) {
debug := utils.NewDebug(utils.USER, name)
defer func() {
debug.Printf("... %s worker finished.", name)
conn.Close()
}()
debug.Printf("%s worker connected to remote address %s", name, conn.RemoteAddr())
// Obtain keys etc.
keyA, e := aeskey.KeyA()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
ivA, e := aeskey.IvA()
if e != nil {
fmt.Printf("%s AES IV error: %v\n", name, e)
return
}
keyB, e := aeskey.KeyB()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
ivB, e := aeskey.IvB()
if e != nil {
fmt.Printf("%s AES IV error: %v\n", name, e)
return
}
sessionKey, e := aeskey.SessionKey()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
//Get input from TCP stream
ibuff := utils.MakeTcpIEncoding(conn)
debug.Printf("Reading nonce N")
nonce, e := ibuff.ReadBinary()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.PrintBuffer(nonce, "Nonce N = ")
debug.Printf("Reading A")
a, e := ibuff.ReadString()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.Printf("A = %v", a)
if a != "student" {
fmt.Printf("Incorrect name for A\n")
return
}
debug.Printf("Reading B")
b, e := ibuff.ReadString()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.Printf("B = %v", b)
if b != "lecturer" {
fmt.Printf("Incorrect name for B\n")
return
}
tokenA, e := ortokens.ReadUserToken(debug, "A", ivA, keyA, ibuff)
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
if tokenA.A != a || tokenA.B != b || !bytes.Equal(tokenA.Nonce, nonce) {
fmt.Printf("Invalid token for A\n")
return
}
tokenB, e := ortokens.ReadUserToken(debug, "B", ivB, keyB, ibuff)
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
if tokenB.A != a || tokenB.B != b || !bytes.Equal(tokenB.Nonce, nonce) {
fmt.Printf("Invalid token for B\n")
return
}
// Send output to TCP stream
obuff := utils.MakeTcpOEncoding(conn)
e = obuff.WriteBinary(nonce)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
// Set up & send A's Key Token
var keytokenA ortokens.KeyToken
keytokenA.UserNonce = tokenA.UserNonce[0:]
keytokenA.Key = sessionKey[0:]
e = ortokens.WriteKeyToken(ivA, keyA, &keytokenA, obuff)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
// Set up & send B's Key Token
var keytokenB ortokens.KeyToken
keytokenB.UserNonce = tokenB.UserNonce[0:]
keytokenB.Key = sessionKey[0:]
e = ortokens.WriteKeyToken(ivB, keyB, &keytokenB, obuff)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
}
func sworker(name string, conn *net.TCPConn) {
debug := utils.NewDebug(utils.USER, name)
defer func() {
debug.Printf("... %s worker finished.", name)
conn.Close()
}()
debug.Printf("%s worker connected to remote address %s", name, conn.RemoteAddr())
// Obtain keys etc.
keyA, e := aeskey.KeyA()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
debug.PrintBuffer(keyA, "A's Key = ")
ivA, e := aeskey.IvA()
if e != nil {
fmt.Printf("AES IV error: %v\n", e)
return
}
debug.PrintBuffer(ivA, "A's IV = ")
keyB, e := aeskey.KeyB()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
debug.PrintBuffer(keyB, "B's Key = ")
ivB, e := aeskey.IvB()
if e != nil {
fmt.Printf("AES IV error: %v\n", e)
return
}
debug.PrintBuffer(ivB, "B's IV = ")
sessionKey, e := aeskey.SessionKey()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
//Get input from TCP stream
ibuff := utils.MakeTcpIEncoding(conn)
debug.Printf("Reading A")
a, e := ibuff.ReadString()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.Printf("A = %v", a)
if a != "student" {
fmt.Printf("Incorrect name for A\n")
return
}
debug.Printf("Reading B")
b, e := ibuff.ReadString()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.Printf("B = %v", b)
if b != "lecturer" {
fmt.Printf("Incorrect name for B\n")
return
}
debug.Printf("Reading nonce N")
nonce, e := ibuff.ReadBinary()
if e != nil {
fmt.Printf("%s Error: %v\n", name, e)
return
}
debug.PrintBuffer(nonce, "Nonce N = ")
// Send output to TCP stream
obuff := utils.MakeTcpOEncoding(conn)
// Set up & send B's Key Token
var token_B nssktokens.BToken
token_B.A = a
token_B.Key = sessionKey[0:]
ciphertext, e := nssktokens.WriteBToken(debug, ivB, keyB, &token_B)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
// Set up & send A's Key Token
var token_A nssktokens.AToken
token_A.Nonce = nonce[0:]
token_A.B = b
token_A.Key = sessionKey[0:]
token_A.CipherText = ciphertext
e = nssktokens.WriteAToken(debug, ivA, keyA, &token_A, obuff)
if e != nil {
fmt.Printf("%s Error: %v\n", e)
return
}
}
func bworker(name string, conn *net.TCPConn) {
debug := utils.NewDebug(utils.USER, name)
defer func() {
debug.Printf("... %s worker finished.", name)
conn.Close()
}()
debug.Printf("%s worker connected to remote address %s", name, conn.RemoteAddr())
// Obtain keys etc.
keyB, e := aeskey.KeyB()
if e != nil {
fmt.Printf("%s AES key error: %v\n", name, e)
return
}
debug.PrintBuffer(keyB, "B's Key = ")
ivB, e := aeskey.IvB()
if e != nil {
fmt.Printf("AES IV error: %v\n", e)
return
}
debug.PrintBuffer(ivB, "B's IV = ")
//Get input from TCP stream
ibuff := utils.MakeTcpIEncoding(conn)
obuff := utils.MakeTcpOEncoding(conn)
token, e := nssktokens.ReadBToken(debug, ivB, keyB, ibuff)
if e != nil {
fmt.Printf("Error: %v\n", e)
return
}
// Respond to A
nonce := uint64(time.Now().Unix())
debug.Printf("Nonce NB = %v", nonce)
tbuff := utils.MakeByteOEncoding(2048)
e = tbuff.WriteUint64(nonce)
if e != nil {
return
}
plaintext, e := tbuff.GetBuffer()
if e != nil {
return
}
iv, e := aeskey.Iv()
if e != nil {
fmt.Printf("AES IV error: %v\n", e)
return
}
debug.PrintBuffer(iv, "Session IV = ")
ciphertext, e := utils.Encrypt(nssktokens.AMP, iv, token.Key[0:], plaintext)
if e != nil {
return
}
e = obuff.WriteBinary(ciphertext)
if e != nil {
return
}
// Check A's response
debug.Printf("Reading protocol message ciphertext")
ciphertext, e = ibuff.ReadBinary()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.PrintBuffer(ciphertext, "Ciphertext = ")
debug.Printf("Decrypting ciphertext")
t, e := utils.Decrypt(nssktokens.AMP, iv, token.Key[0:], ciphertext)
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.PrintBuffer(t, "Plaintext = ")
sbuff := utils.MakeByteIEncoding(t)
debug.Printf("Reading nonce-1")
n, e := sbuff.ReadUint64()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.Printf("NB-1 = %v", n)
if n != nonce-1 {
fmt.Printf("Ivalid nonce\n")
return
}
// Get cipphertext message
debug.Printf("Reading protocol message ciphertext")
ciphertext, e = ibuff.ReadBinary()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.PrintBuffer(ciphertext, "Ciphertext = ")
debug.Printf("Decrypting ciphertext")
t, e = utils.Decrypt(nssktokens.AMP, iv, token.Key[0:], ciphertext)
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.PrintBuffer(t, "Plaintext = ")
sbuff = utils.MakeByteIEncoding(t)
debug.Printf("Reading message")
msg, e := sbuff.ReadString()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
debug.Printf("Message = %s", msg)
// Send response
//msg = strings.ToUpper(strings.Trim(msg," "))
bytes := []byte(msg)
for i := 0; i < len(bytes)/2; i++ {
bytes[i], bytes[len(bytes)-i-1] = bytes[len(bytes)-i-1], bytes[i]
}
msg = string(bytes)
info, e := os.Lstat("./.msg")
if e == nil && info.Mode().IsRegular() {
msg = "This is a fixed message to prevent cheating"
}
pbuff := utils.MakeByteOEncoding(2048)
e = pbuff.WriteString(msg)
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
plaintext, e = pbuff.GetBuffer()
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
ciphertext, e = utils.Encrypt(nssktokens.AMP, iv, token.Key[0:], plaintext)
if e != nil {
fmt.Printf("Encryption error: %v\n", e)
return
}
e = obuff.WriteBinary(ciphertext)
if e != nil {
fmt.Printf("Error: %s\n", e)
return
}
}