Perhaps it would be better to come up with a design that reflects the current state of cryptography rather than the history of the subject.
As you might have seen, I've been toying with a design that shows an encryption chain with a wave of random-looking ones and zeroes coming out from the right side. It occurred to me that the design would be a bit more meaningful (and probably more symmetrical) if it also showed some sort of information going in on the left side. So I came up with the following:
HTTP/1.1 200 OK\r\nDate: Fri, 13 Feb 2009 23:31:30 GMT\r\nContent-Type: text/html;charset=utf-8\r\nContent-Length: 46708\r\nSet-Cookie: SESSION_ID=SGVsbG8gV29ybGQK; path=/; domain=example.com; secure;
\x89PNG\r\n\x1a\x00\x00\x00\rIHDR\x00\x00\x00\x10\x00\x00\x00\x10\x08\x02\x00\x00\x00\x90\x91h6\x00\x00\x00MIDATx\x9cb\xf8\x8f\x04\x18p\x00\x145\xc8\xaa\xc1\,\x08Y\x0f\x03A\xd5hz\x18\x88Q\x8d\xac\x87\
Content-Type: multipart/signed;\r\n boundary="--3243f6a8885a308d-313198a2";\r\n protocol="application/pgp-signature";\r\n micalg=pgp-sha256\r\nMime-Version: 1.0\r\nSubject: See attached document\r\nFr
-----BEGIN CERTIFICATE-----\nMIIFTTCCBDWgAwIBAgISESFabet2Ut7cK/VvlXe2kDzoMA0GCSqGSIb3DQEBBQUA\nMF0xCzAJBgNVBAYTAkJFMRkwFwYDVQQKExBHbG9iYWxTaWduIG52LXNhMTMwMQYD\nVQQDEypHbG9iYWxTaWduIE9yZ2FuaXphdGlvbiB
my @top_passwords = qw(123456 password 12345 12345678 qwerty 123456789 1234 baseball dragon football 1234567 monkey letmein abc123 111111 mustang access shadow master michael superman 696969 123123 ba
CREATE TABLE IF NOT EXISTS `users` (\n `user_id` INT NOT NULL AUTO_INCREMENT PRIMARY KEY,\n `username` TEXT NOT NULL,\n `password` CHAR(60) BINARY NOT NULL,\n `email` TEXT NOT NULL) ENGINE=MyISAM DEFA
action=Update Payment Details\nuser_id=2653589793\nname=Jane Doe\ncard_number=4626433832795028\nCSC=841\nhome_address=9 Mathison Avenue\\nMilton Keynes\\nMK71 6AT\ndelivery_address=\nnonce=3243f6a8885
ECParameters ::= SEQUENCE {\n version INTEGER { ecpVer1(1) } (ecpVer1),\n fieldID FieldID {{FieldTypes}},\n curve Curve,\n base ECPoint,\n order INTEGER,\n cofactor INTEGER OPTIONAL,\n ... \n}
(Note: I wouldn't intend for all of this text to be visible. I made the strings quite long so they can be faded out at both ends. Just a short chunk from the middle will probably be sufficient.)
These strings (all truncated to 200 chars) represent:
- Headers of a typical HTTP request
- This PNG image:

- Email headers
- The current HTTP certificate for stackexchange.com (retrieved via
openssl s_client -showcerts -connect stackexchange.com:443
)
- A snippet of Perl containing the most popular passwords of 2014
- A MySQL statement to create a table of users and passwords
- Form data containing a credit card number (invalid, of course)
ECParameters
struct from the Internet X.509 Public Key Infrastructure
Since some people might be worried about nefarious information being sneaked into the site header, I decided to use the digits of π (in bases 10 and 16) for the random-looking parts of this data, except for the timestamp in the first line (equal to 1234567890 in Unix time.
I also made a bunch of binary digits for the data coming out the other side (π again: 11.0010010000111...)
11001001000011111101101010100010001000010110100011000010001101001100010011000110011000101000101110000000110111000001110011010001001010010000001001001110000010001000101001100111110011000111010000000010
00001011101111101010011000111011000100111001101100100010010100010100101000001000011110011000111000110100000001001101110111101111100101010001100110110011110011010011101001000011000110110011000000101011
00001010011011011111001001011111000101000011011101001111111000010011010101101101011011010101000111000010010001011110010010000101101101010111011001100010010111100111111011000110111101000100110001000010
11101001101001100011011111101101011010110000101111111111010111001011011011110100000001101011011111101101111011100011100001101011111110110101101010001001100111111010010110101110100111110010010000010001
01111100010010110001111111100110010010010010100001100110010100011110110011100100010110110011110111000010000000000111110010111000101000010110001110111111000001011001100011011010010010000011011000011100
01010101110100111001101001101001000101100011111110101000111111010010010011001111010111111000001101100101010111010010001111011100101000111010110110010110000111000110001011110011010101100010000010000101
01010010101110111001111011010101001010010000011101110000100101101001011001101101011001110000110000110101010011100100101010111100100110000000010011110001011101000110110000001000110010100001100000100001
01111100001100101001000001011110010001100010111000110110110011100011101111100011100111100111011100101100000110000000111010000110000000111001101100100111100000111010001011101100000001111010001010001111