The depth of encyption of the ShyFile algorithm

Imagine you encrypt a file with a key that conists of only a single character, and one character was also the maximum length possible. A potential hacker would then need to go through all possible characters on your keyboard to decode your file, i.e. he needs to cycle through about 108 possibilities.

Why 108? The user can choose from about 108 printable characters that can be entered using, in this case, a German standard keyboard: abcdefghijklmnopqrstuvwxyzäöüßABCDEFGHIJKLMNOPQRS TUVWXYZ ÄÖÜ1234567890§$%&=+-*^/\()<>[]{}_~#²|@³?!:,;.'`´"µ° [SPACE]

Those ASCII code characters not listed here cannot be used in a key entry because they are either non-printable or interfere with the software. Keyboards made to be used in other western countries will allow the user to choose from slightly different characters, but yet also from about 108 eligible for use by ShyFile.

A key entry made of two characters will urge a potential hacker to go through 108 times 108 possibilities. 3 characters require the hacker to go through 108 times 108 times 108, and so on.

Why is it called a 6bit encryption if one plain text character is hidden among 108 possible characters?
Since the amount of 108 characters does not really equal 2 to the power of 7 [=128] one should not proceed on the assumption of having a 7bit resolution per character. Even though 108 slightly tops 2 to the power of 6 [=64] it seems more appropriate to proceed by calling it conservatively a 6bit resolution per character.

The maximum length of a ShyFile key entry is 1,024 characters. ShyFile offers the following sizes of key entries and their reciprocal depth of encryption:

key size	depth of encryption	possible key entries
32 characters	32 characters * 6bit = 192bit	2 ^ 192
64 characters	64 characters * 6bit = 384bit	2 ^ 384
128 characters	128 characters * 6bit = 768bit	2 ^ 768
256 characters	256 characters * 6bit = 1536bit	2 ^ 1536
512 characters	512 characters * 6bit = 3072bit	2 ^ 3072
1024 characters	1,024 characters * 6bit = 6144bit	2 ^ 6144

Remember that 128bit is the standard depth of encryption of most of the Internet banking information technology.

Brute Force Attack

An attack on an encoded file that will go through all possible key entries, without exception, is called a Brute Force Attack. No characters that seem less likely or the combination thereof unusual are ruled out in the outset by a Brute Force Attack. Unlike a Brute Force Attack there are smarter attacks out there that will neglect certain characters when trying possible key entries, i.e. a stream of characters of sheer punctuation. Nor are any characters used that don't even make whole words etc. However, those attacks doing a preselection are not more likely to succeed when ShyFile's random key generator is used to create a key entry that consists of an unusual combination of values.

Click here to learn about the Project RC5 by distributed.net trying a Brute Force Attack on symmetric encryption. To be on Terra Firm in terms of symmetric encryption you should go for a depth of encryption of nothing less than 80bit.

If, according to the RC5 project, an intrusion into an encoded document of 56bit would take 250 days (about 0.68 years), the time that is needed to hack a document encoded in 6144bit will have to be multiplied by the factor of 2 ^ ( 6,144-56 ). This means that the time necessary to succeed in such a Brute Force Attack equals 0.68 * (2 ^ 6,088) years.

To make this equation easier, we round off 0.68 years to 0.5 years which is only to ShyFile's disadvantage. Accordingly, 0.5 * (2 ^ 6,088) equal 2 ^ 6,087 years. Since it is not likely that someone actually trying that many possibilities (and someone who had that many trillions of billions of years available) would not succeed until the very last possible key entry, we should rather expect him to succeed after having completed about half of it. Therefore we calculate with 2 ^ 6,086 years someone would require to crack a ShyFile. That many digits are not depicted on this page to save some space.

Chosen Plaintext Attack

If a document containing plain text information is encoded over and over again at every time using nearly the same key entry that differs only from the one before in a single character, some similarities may be found within the encoded files. Those similarities can eventually offer some knowledge about the actual algorithm to establish a Code Book in which a certain encoded character can be recognized as a previously known plain text character.

Though, the exact same text encoded over and over again by ShyFile using the nearly the same key entry will not resemble the one before. Have a look:

Sample encryption A

Key	no more large industrial espionage
Plain text	This is a Chosen Plaintext Attack!

Encoded text:
START_CUT/COPY_HERE(((((0500D8A5FA2BAB960BC465B0B4828CD A8197C9142433A3AD9B6E201FE7E414F1B8CA600545CECECCADFE1C 36C1EA077198E32A9F1A407349F37FE266C6656C29A2782A837EB7D AA1FEEA014FC49A3E2F66E214CE68FB)))))END_CUT / COPY_HERE

Sample encryption B

Key	so more large industrial espionage
Plain text	This is a Chosen Plaintext Attack!

Encoded text:
START_CUT/COPY_HERE(((((0500FF74084D390C22E6B9B6DE2ACC7 1D5788EE29470C334106FA57410346ADF48B49C300F698628BBD456 7E49D91D1C522F79631F66368C3D445AD0C8DA057ABCB934D40098F 72377E64C716C5EF00B825E056085F1)))))END_CUT / COPY_HERE

The encoded data stream (cipher text) consists of 16 different characters from 0 to F. Therefore an average of one sixteenth of all characters (6.25%) between sample encryption A & B are likely to match anyway. Both data stream as depicted above consist of 170 characters each. A conformity of characters of both encoded data streams of up to 10.625 out of 170 characters (6.25%) would still be within the boundaries of a random probability. In this case, however, all characters of both encoded data streams have a conformity of only 11 out of 168 characters (6.5%).

A conformity of all bits of the two encoded data streams of up to 340 out of 680 bits (50%) would be within the boundaries of a random probability because there is a bit-state probability of 0 and 1. All bits representing encoded characters in this data stream, in this case, have a conformity of 368 out of 672 bits (54.7%). This is nothing more than a fair random result, i.e. no Chosen Plain Text Attack software could gather some crucial information out of this.

ShyFile's max. depth of encryption of 6,144-bit renders 2 to the power of 6,144 possibilities, which means a potential hacker would need to cycle through 33751521821438561184911174488682640477 48245269061354378998711510846650037846741324165030982375991521461354629508635213511 72060726207028052137864298272611904952952097250362148614445522452710018844423313364 63841183659029156587178439044751051570054376203776342097110897640119327918012337424 31335591935963965256787178128676927071102670915735292434877751557451257920743012496 07450177138114756335603617462402313721869876332818900039751245174104362327517860532 58030904248989784343373580020429064399723981629210039686199812017059962040894145649 61314189937345799013611012403308226844529975921427055702069783744472962847044555359 73834352324658581243318792909226969802227356673323935612163123006229898288296485668 39376565747897273836250008772899562390160189852318683176499778475449534897302151083 44853528836713359219844441024401290307061953847602312108701182160272713034206236029 26941969150307534755710471876215776777340159710612862662407760001997614594714449404 63293093653202098729357658867135004032110599475307618336429187822239334863636668860 33751607602502380752432887916214214980515412817950340539071099437378350194821173072 28603598377500903352726158479078471240691411993347222620555343776990543813708613373 37471574548468743992660475775028572280267994135704993835355977695442635432946193561 82101708973662737907113148393068453262295239889771549134494221616994454081134662808 94218636839379204569968733539087852205907225185859091066058115321172389416793465879 84132366957891357781759795220034581173473479726235700321529495539776440692644558284 46934887067105599598720306273052527639602696291671835862984552055649515251359787092 79827857746749297650724851496824627944089261272676160606239233708393590584348466105 01532154221129624066335698266050975882792155955005954460099419877138745992453542401 993667168494168245722096801075794308992327588609520244453197182140416 possible key entries in order to crack a ShyFile. That is a figure with 1,850 digits.