HasTEK_Easy_Challenges) Simple string encryption.

Bit
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HasTEK_Easy_Challenges) Simple string encryption. May 11, 2017 22:49:45 GMT

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Post by Bit on May 11, 2017 22:49:45 GMT

This one is very simple, yet not as "easy" as my novice series.
As always, you are welcome to golf it if you'd like, but not necessary, just like explaining your code.
The task:
*Make two functions, one to "encrypt" a string, and one to "decrypt" it.
*Bonus if you can add a key that needs to be used in order to recover the original string.
As always, no hard-coding allowed, and it must work without an internet connection, along with being use-able in any natural circumstance.
Also, don't forget to put the language name next to the solution.
Has out.

NOTE: Encryption, in this case, means to at least make it unable to recover the original string with basic functions. (Such as :reverse() or :gsub() in Lua.)

Last Edit: May 11, 2017 22:53:26 GMT by Bit

Hey, I'm Has and I love editing.
Now stop, Hammertime!

AxonMega
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HasTEK_Easy_Challenges) Simple string encryption. May 12, 2017 21:16:24 GMT Josh and Bit like this

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Post by AxonMega on May 12, 2017 21:16:24 GMT

Mine is Lua, un-golfed. It randomizes the ids and order of the characters in the given string.

math.randomseed(tick())

local function generateKey(length) --this generates an array with the given length containing numbers in the range of 1 to length
	local key = {1}
	for i = 2, length do
		table.insert(key, math.random(1, #key), i)
	end
	return key
end

local function encrypt(str, key)
	local charList = {}
	for i = 1, #str do
		table.insert(charList, str:sub(i, i))
	end
	for i, char in ipairs(charList) do
		charList[i] = string.char(char:byte() + key[i])
	end
	local newList = {}
	for a, b in ipairs(key) do
		newList[a] = charList[b]
	end
	return table.concat(newList)
end

local function decrypt(str, key)
	local charList = {}
	for i = 1, #str do
		table.insert(charList, str:sub(i, i))
	end
	local newList = {}
	for a, b in ipairs(key) do
		newList[b] = charList[a]
	end
	for i, char in ipairs(newList) do
		newList[i] = string.char(char:byte() - key[i])
	end
	return table.concat(newList)
end

--example:

local str = "This is a secret message!"

local key = generateKey(#str)

local encrypted = encrypt(str, key)

print("Encrypted string:", encrypted)

decrypted = decrypt(encrypted, key)

print("Decrypted string:", decrypted)

Bit Administrator Veteran Poot. Posts: 187 ROBLOX Username: Narqwhal	HasTEK_Easy_Challenges) Simple string encryption. May 12, 2017 22:25:45 GMT Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by Bit on May 12, 2017 22:25:45 GMT Not bad.
	Last Edit: May 12, 2017 22:26:25 GMT by Bit Hey, I'm Has and I love editing. Now stop, Hammertime!

AxonMega Teacher Keeping everyone informed with the latest updates! Posts: 41 ROBLOX Username: AxonMega	HasTEK_Easy_Challenges) Simple string encryption. May 12, 2017 22:37:46 GMT Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by AxonMega on May 12, 2017 22:37:46 GMT Thank you.

Bit Administrator Veteran Poot. Posts: 187 ROBLOX Username: Narqwhal	HasTEK_Easy_Challenges) Simple string encryption. May 13, 2017 1:01:18 GMT Quote Select Post Deselect Post Link to Post Member Give Gift Back to Top Post by Bit on May 13, 2017 1:01:18 GMT I'll post my solution later, waiting for more answers.
	Hey, I'm Has and I love editing. Now stop, Hammertime!

cntkillme
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Posts: 43

HasTEK_Easy_Challenges) Simple string encryption. May 14, 2017 9:45:09 GMT Bit likes this

Quote

Post by cntkillme on May 14, 2017 9:45:09 GMT

Here's a fun concept, use RNG for your displacements for each character and the seed as the key.
For example:


local function encrypt(str, key)
  math.randomseed(key)
  return str:gsub(".", function(char)
    return string.char((char:byte() + math.random(255)) % 256)
  end)
end

local function decrypt(str, key)
  math.randomseed(key)
  return str:gsub(".", function(char)
    return string.char((char:byte() - math.random(255)) % 256)
  end)
end

Last Edit: May 14, 2017 9:45:26 GMT by cntkillme

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HasTEK_Easy_Challenges) Simple string encryption.

Post by Bit on May 11, 2017 22:49:45 GMT

Post by AxonMega on May 12, 2017 21:16:24 GMT

Post by Bit on May 12, 2017 22:25:45 GMT

Post by AxonMega on May 12, 2017 22:37:46 GMT

Post by Bit on May 13, 2017 1:01:18 GMT

Post by cntkillme on May 14, 2017 9:45:09 GMT

We have moved! Find our active server with over 6,500 members at https://discord.gg/scf