What is this riddle?

[Hussein Baghdadi]

Hi,
On one of job boards, the employer posted this riddle for extra points:

NTc6Njg6NjU6NmU6MjA6Nzk6NmY6NzU6MjA6NjU6NmQ6NjE6Njk6NmM6MjA6NzU6NzM6MmM6MjA6NjM6Njg6NjE6NmU6Njc6NjU6MjA6NzQ6Njg6NjU6MjA6NzM6NzU6NjI6NmE6NjU6NjM6NzQ6MjA6NzQ6NmY6MjA6MjI6NTQ6Njg6NjE6NzQ6Mjc6NzM6MjA6NjE6NmM6NmM6MjA6Nzk6NmY6NzU6MjA6Njc6NmY6NzQ6M2Y6MjI6MjA6NjE6NmU6NjQ6MjA6Nzk6NmY6NzU6NzI6MjA6NzI6NjU6NzM6NzU6NmQ6NjU6MjA6Nzc6Njk6NmM6NmM6MjA6NmQ6NjE6NmI6NjU6MjA6Njk6NzQ6MjA6NzQ6NmY6MjA6NzQ6Njg6NjU6MjA6NzQ6NmY6NzA6MjA6NmY6NjY6MjA6NzQ6Njg6NjU6MjA6NzI6NjU6NzY6Njk6NjU6Nzc6MjA6NzM6NzQ6NjE6NjM6NmI=

Seriously, what is this?

[Tim Moores]

Looks like something that was encoded with base-64.

[Hussein Baghdadi]

How did you figure it out that it is encoded with base-64?

[Tim Moores]

Experience If you'd seen multiple base-64 encoded strings you'd have noticed as well.

[Hussein Baghdadi]

Any pattern to recognize base-64 encoded strings?
The first time I saw it, I felt it is about hashing or encoding but not really as accurate as your answer

[Tim Moores]

The trailing equals sign is a give-away. And, of course, the limited range of characters (just letters and digits, for the most part).

[Dave Trower]

Here are the steps to decode:
1) Go to a base 64 base decode website. There are several, but I went to http://www.opinionatedgeek.com/dotnet/tools/base64decode/
I copied what you put in this post and it decoded to this:
57:68:65:6e:20:79:6f:75:20:65:6d:61:69:6c:20:75:73:2c:20:63:68:61:6e:67:65:20:74:68:65:20:73:75:62:6a:65:63:74:20:74:6f:20:22:54:68:61:74:27:73:20:61:6c:6c:20:79:6f:75:20:67:6f:74:3f:22:20:61:6e:64:20:79:6f:75:72:20:72:65:73:75:6d:65:20:77:69:6c:6c:20:6d:61:6b:65:20:69:74:20:74:6f:20:74:68:65:20:74:6f:70:20:6f:66:20:74:68:65:20:72:65:76:69:65:77:20:73:74:61:63:6b

2) What it decoded to looks like a bunch of 2 digit hexadecimal numbers separated by a colon. The following program converts this to an ascii string.

import java.util.*;
public class Decode {
	public static void main(String[] args) {
		String code = "57:68:65:6e:20:79:6f:75:20:65:6d:61:69:6c:20:75:73:2c:20:63:68:61:6e:67:65:20:74:68:65:20:73:75:62:6a:65:63:74:20:74:6f:20:22:54:68:61:74:27:73:20:61:6c:6c:20:79:6f:75:20:67:6f:74:3f:22:20:61:6e:64:20:79:6f:75:72:20:72:65:73:75:6d:65:20:77:69:6c:6c:20:6d:61:6b:65:20:69:74:20:74:6f:20:74:68:65:20:74:6f:70:20:6f:66:20:74:68:65:20:72:65:76:69:65:77:20:73:74:61:63:6b";
		StringTokenizer st = new StringTokenizer(code,":");
		String answer = "";
		while(st.hasMoreTokens()) {
			String token = st.nextToken();
			answer += hexToAscii(token);
		}
		System.out.println(answer);
	}
	public static String hexToAscii(String hexCode) {
		String firstHexDigit = hexCode.substring(0,1);
		String secondHexDigit =  hexCode.substring(1,2);
		int hexValueOne = Integer.parseInt(firstHexDigit, 16);
		int hexValueTwo = Integer.parseInt(secondHexDigit, 16);
		int asciiValue = hexValueOne*16 + hexValueTwo;		
		byte[] bytes = new byte[1];
		bytes[0] = (byte)asciiValue;
		String letter = new String(bytes);
		return letter;
	}
}

Here is the answer:
When you email us, change the subject to "That's all you got?" and your resume will make it to the top of the review stack

[Ryan McGuire]

I'm disappointed... the hex-to-character decoding didn't use EDCDIC?

BTW, Integer.parseInt(hexCode, 16);

[Ryan McGuire]

Ryan McGuire wrote:I'm disappointed... the hex-to-character decoding didn't use EDCDIC?

Before anyone else points it out...
s/EDCDIC/EBCDIC/

Nothing worse than a typo when you're trying to show off.

[Ashish L. Sharma]

Dave Trower wrote:Here are the steps to decode:
1) Go to a base 64 base decode website. There are several, but I went to http://www.opinionatedgeek.com/dotnet/tools/base64decode/
I copied what you put in this post and it decoded to this:
57:68:65:6e:20:79:6f:75:20:65:6d:61:69:6c:20:75:73:2c:20:63:68:61:6e:67:65:20:74:68:65:20:73:75:62:6a:65:63:74:20:74:6f:20:22:54:68:61:74:27:73:20:61:6c:6c:20:79:6f:75:20:67:6f:74:3f:22:20:61:6e:64:20:79:6f:75:72:20:72:65:73:75:6d:65:20:77:69:6c:6c:20:6d:61:6b:65:20:69:74:20:74:6f:20:74:68:65:20:74:6f:70:20:6f:66:20:74:68:65:20:72:65:76:69:65:77:20:73:74:61:63:6b

2) What it decoded to looks like a bunch of 2 digit hexadecimal numbers separated by a colon. The following program converts this to an ascii string.

import java.util.*;
public class Decode {
	public static void main(String[] args) {
		String code = "57:68:65:6e:20:79:6f:75:20:65:6d:61:69:6c:20:75:73:2c:20:63:68:61:6e:67:65:20:74:68:65:20:73:75:62:6a:65:63:74:20:74:6f:20:22:54:68:61:74:27:73:20:61:6c:6c:20:79:6f:75:20:67:6f:74:3f:22:20:61:6e:64:20:79:6f:75:72:20:72:65:73:75:6d:65:20:77:69:6c:6c:20:6d:61:6b:65:20:69:74:20:74:6f:20:74:68:65:20:74:6f:70:20:6f:66:20:74:68:65:20:72:65:76:69:65:77:20:73:74:61:63:6b";
		StringTokenizer st = new StringTokenizer(code,":");
		String answer = "";
		while(st.hasMoreTokens()) {
			String token = st.nextToken();
			answer += hexToAscii(token);
		}
		System.out.println(answer);
	}
	public static String hexToAscii(String hexCode) {
		String firstHexDigit = hexCode.substring(0,1);
		String secondHexDigit =  hexCode.substring(1,2);
		int hexValueOne = Integer.parseInt(firstHexDigit, 16);
		int hexValueTwo = Integer.parseInt(secondHexDigit, 16);
		int asciiValue = hexValueOne*16 + hexValueTwo;		
		byte[] bytes = new byte[1];
		bytes[0] = (byte)asciiValue;
		String letter = new String(bytes);
		return letter;
	}
}

Here is the answer:
When you email us, change the subject to "That's all you got?" and your resume will make it to the top of the review stack

Hats Off to you Sir Great Code !!!