One-time pad: Difference between revisions
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* [http://search.cpan.org/~sifukurt/Crypt-OTP-2.00/OTP.pm Crypt-OTP-2.00] on CPAN (Perl)
<br><br>
=={{header|Kotlin}}==
This uses the JDK's SecureRandom class for generating cryptographically strong random numbers. For convenience all three sub-tasks are catered for by a single, menu-based, program.
<lang scala>// version 1.2.31
import java.io.File
import java.security.SecureRandom
const val CHARS_PER_LINE = 48
const val CHUNK_SIZE = 6
const val COLS = 8
const val DEMO = true // would normally be set to false
enum class FileType { OTP, ENC, DEC }
fun Char.isAlpha() = this in 'A'..'Z'
fun String.toAlpha() = this.filter { it.isAlpha() }
fun String.isOtpRelated() = endsWith(".1tp") || endsWith(".1tp_cpy") ||
endsWith(".1tp_enc") || endsWith(".1tp_dec")
fun makePad(nLines: Int): String {
val nChars = nLines * CHARS_PER_LINE
val sr = SecureRandom()
val sb = StringBuilder(nChars)
/* generate random upper case letters */
for (i in 0 until nChars) sb.append((sr.nextInt(26) + 65).toChar())
return sb.toString().inChunks(nLines, FileType.OTP)
}
fun vigenere(text: String, key: String, encrypt: Boolean = true): String {
val sb = StringBuilder(text.length)
for ((i, c) in text.withIndex()) {
val ci = if (encrypt)
(c.toInt() + key[i].toInt() - 130) % 26
else
(c.toInt() - key[i].toInt() + 26) % 26
sb.append((ci + 65).toChar())
}
val temp = sb.length % CHARS_PER_LINE
if (temp > 0) { // pad with random characters so each line is a full one
val sr = SecureRandom()
for (i in temp until CHARS_PER_LINE) sb.append((sr.nextInt(26) + 65).toChar())
}
val ft = if (encrypt) FileType.ENC else FileType.DEC
return sb.toString().inChunks(sb.length / CHARS_PER_LINE, ft)
}
fun String.inChunks(nLines: Int, ft: FileType): String {
val chunks = this.chunked(CHUNK_SIZE)
val sb = StringBuilder(this.length + nLines * (COLS + 1))
for (i in 0 until nLines) {
val j = i * COLS
sb.append(" ${chunks.subList(j, j + COLS).joinToString(" ")}\n")
}
val s = " file\n" + sb.toString()
return when (ft) {
FileType.OTP -> "# OTP" + s
FileType.ENC -> "# Encrypted" + s
FileType.DEC -> "# Decrypted" + s
}
}
fun menu(): Int {
println("""
|
|1. Create one time pad file.
|
|2. Delete one time pad file.
|
|3. List one time pad files.
|
|4. Encrypt plain text.
|
|5. Decrypt cipher text.
|
|6. Quit program.
|
""".trimMargin())
var choice: Int?
do {
print("Your choice (1 to 6) : ")
choice = readLine()!!.toIntOrNull()
}
while (choice == null || choice !in 1..6)
return choice
}
fun main(args: Array<String>) {
mainLoop@ while (true) {
val choice = menu()
println()
when (choice) {
1 -> { // Create OTP
println("Note that encrypted lines always contain 48 characters.\n")
print("OTP file name to create (without extension) : ")
val fileName = readLine()!! + ".1tp"
var nLines: Int?
do {
print("Number of lines in OTP (max 1000) : ")
nLines = readLine()!!.toIntOrNull()
}
while (nLines == null || nLines !in 1..1000)
val key = makePad(nLines)
File(fileName).writeText(key)
println("\n'$fileName' has been created in the current directory.")
if (DEMO) {
// a copy of the OTP file would normally be on a different machine
val fileName2 = fileName + "_cpy" // copy for decryption
File(fileName2).writeText(key)
println("'$fileName2' has been created in the current directory.")
println("\nThe contents of these files are :\n")
println(key)
}
}
2 -> { // Delete OTP
println("Note that this will also delete ALL associated files.\n")
print("OTP file name to delete (without extension) : ")
val toDelete1 = readLine()!! + ".1tp"
val toDelete2 = toDelete1 + "_cpy"
val toDelete3 = toDelete1 + "_enc"
val toDelete4 = toDelete1 + "_dec"
val allToDelete = listOf(toDelete1, toDelete2, toDelete3, toDelete4)
var deleted = 0
println()
for (name in allToDelete) {
val f = File(name)
if (f.exists()) {
f.delete()
deleted++
println("'$name' has been deleted from the current directory.")
}
}
if (deleted == 0) println("There are no files to delete.")
}
3 -> { // List OTPs
println("The OTP (and related) files in the current directory are:\n")
val otpFiles = File(".").listFiles().filter {
it.isFile() && it.name.isOtpRelated()
}.map { it.name }.toMutableList()
otpFiles.sort()
println(otpFiles.joinToString("\n"))
}
4 -> { // Encrypt
print("OTP file name to use (without extension) : ")
val keyFile = readLine()!! + ".1tp"
val kf = File(keyFile)
if (kf.exists()) {
val lines = File(keyFile).readLines().toMutableList()
var first = lines.size
for (i in 0 until lines.size) {
if (lines[i].startsWith(" ")) {
first = i
break
}
}
if (first == lines.size) {
println("\nThat file has no unused lines.")
continue@mainLoop
}
val lines2 = lines.drop(first) // get rid of comments and used lines
println("Text to encrypt :-\n")
val text = readLine()!!.toUpperCase().toAlpha()
val len = text.length
var nLines = len / CHARS_PER_LINE
if (len % CHARS_PER_LINE > 0) nLines++
if (lines2.size >= nLines) {
val key = lines2.take(nLines).joinToString("").toAlpha()
val encrypted = vigenere(text, key)
val encFile = keyFile + "_enc"
File(encFile).writeText(encrypted)
println("\n'$encFile' has been created in the current directory.")
for (i in first until first + nLines) {
lines[i] = "-" + lines[i].drop(1)
}
File(keyFile).writeText(lines.joinToString("\n"))
if (DEMO) {
println("\nThe contents of the encrypted file are :\n")
println(encrypted)
}
}
else println("Not enough lines left in that file to do encryption")
}
else println("\nThat file does not exist.")
}
5 -> { // Decrypt
print("OTP file name to use (without extension) : ")
val keyFile = readLine()!! + ".1tp_cpy"
val kf = File(keyFile)
if (kf.exists()) {
val keyLines = File(keyFile).readLines().toMutableList()
var first = keyLines.size
for (i in 0 until keyLines.size) {
if (keyLines[i].startsWith(" ")) {
first = i
break
}
}
if (first == keyLines.size) {
println("\nThat file has no unused lines.")
continue@mainLoop
}
val keyLines2 = keyLines.drop(first) // get rid of comments and used lines
val encFile = keyFile.dropLast(3) + "enc"
val ef = File(encFile)
if (ef.exists()) {
val encLines = File(encFile).readLines().drop(1) // exclude comment line
val nLines = encLines.size
if (keyLines2.size >= nLines) {
val encrypted = encLines.joinToString("").toAlpha()
val key = keyLines2.take(nLines).joinToString("").toAlpha()
val decrypted = vigenere(encrypted, key, false)
val decFile = keyFile.dropLast(3) + "dec"
File(decFile).writeText(decrypted)
println("\n'$decFile' has been created in the current directory.")
for (i in first until first + nLines) {
keyLines[i] = "-" + keyLines[i].drop(1)
}
File(keyFile).writeText(keyLines.joinToString("\n"))
if (DEMO) {
println("\nThe contents of the decrypted file are :\n")
println(decrypted)
}
}
else println("Not enough lines left in that file to do decryption")
}
else println("\n'$encFile' is missing.")
}
else println("\nThat file does not exist.")
}
else -> return // Quit
}
}
}</lang>
{{out}}
Input/output for a sample session. In the interests of brevity, --<menu>-- indicates the re-display of the menu after the previous choice has been processed:
<pre>
1. Create one time pad file.
2. Delete one time pad file.
3. List one time pad files.
4. Encrypt plain text.
5. Decrypt cipher text.
6. Quit program.
Your choice (1 to 6) : 1
Note that encrypted lines always contain 48 characters.
OTP file name to create (without extension) : user1
Number of lines in OTP (max 1000) : 4
'user1.1tp' has been created in the current directory.
'user1.1tp_cpy' has been created in the current directory.
The contents of these files are :
# OTP file
MZSAVH VHJLRS YLFXZB JWAHSN AHPCSE RUJMFX ZZPMFB QTTNLM
LDANXY LGJEBV IRKDTR NHKOPG ZDUBDC KOOWZC HEBKWC YAHOFY
DYPCXG TGCBXC VFETFM VOTHNI ZCGKNL QONXYE IDCROZ LHLWMN
YWSGDO YYSNNV QMOJFM AHVOGP CDFAKM HZCWEX CEAXXV INKAEO
--<menu>--
Your choice (1 to 6) : 3
The OTP (and related) files in the current directory are:
user1.1tp
user1.1tp_cpy
--<menu>--
Your choice (1 to 6) : 4
OTP file name to use (without extension) : user1
Text to encrypt :-
Beware the Jabberwock, my son! The jaws that bite, the claws that catch!
'user1.1tp_enc' has been created in the current directory.
The contents of the encrypted file are :
# Encrypted file
NDOAML OONURT ZPWTND TIYZGA TOTLSA JNQMYY HSTFMF SETJDF
SDTPXR NNHVAO YSCVZU UTLAFM PEWGRH OJRCTF IOVEHK ZKETBQ
--<menu>--
Your choice (1 to 6) : 5
OTP file name to use (without extension) : user1
'user1.1tp_dec' has been created in the current directory.
The contents of the decrypted file are :
# Decrypted file
BEWARE THEJAB BERWOC KMYSON THEJAW STHATB ITETHE CLAWST
HATCAT CHYRZT QBSSGD HMBMQG QBCFOF EVDGUD BKUULI BKXFWS
--<menu>-
Your choice (1 to 6) : 2
Note that this will also delete ALL associated files.
OTP file name to delete (without extension) : user1
'user1.1tp' has been deleted from the current directory.
'user1.1tp_cpy' has been deleted from the current directory.
'user1.1tp_enc' has been deleted from the current directory.
'user1.1tp_dec' has been deleted from the current directory.
--<menu>--
Your choice (1 to 6) : 6
</pre>
=={{header|Perl 6}}==
{{works with|Rakudo|2017.10}}
Line 167 ⟶ 507:
JISNOS CMLRPW TFGELQ HPTMRN SHBBDP AIVDAC CEWIFH TRLQVK
FRBUUC GDCQHQ CEEURS RGVWVT JZIQLP NQCABF BWUPUI UDTZAF</pre>
=={{header|Racket}}==
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