WO2000070816A1

WO2000070816A1 - Encryption and decryption method, data processing program, and encryption and decryption device

Info

Publication number: WO2000070816A1
Application number: PCT/EP1999/009865
Authority: WO
Inventors: Thomas Oberlechner; Oleksandr Demenshyn
Original assignee: Telesens Ag
Priority date: 1999-05-18
Filing date: 1999-12-13
Publication date: 2000-11-23
Also published as: AU3038000A; DE19922780A1

Abstract

The invention relates to an encryption method for encrypting a sequence of plain characters and to a corresponding decryption method, data processing program and a device for carrying out said method. In the encryption method, a plain character P is linked to a random character by means of an operator OP2 to produce the encrypted character Q. In the decryption process, the encrypted character is linked to the random character, using the inverse operator OP2 to produce the plain character. The random character is calculated, using a one-dimensional memory area and a preceding encrypted character. The one-dimensional memory area can contain constant values and the link back to preceding encrypted characters takes place, using an inverse link memory F, or the values themselves in the one-dimensional memory area are changed, based on preceding encrypted characters.

Description

Encryption method, decryption method, data processing program, encryption device and decryption device

The present invention relates to an encryption method of the type mentioned in the preamble of claim 1 or 3 and a decryption method of the type mentioned in the preamble of patent claim 16 or 18. The invention further relates to a data processing program, an encryption device and a decryption device

Such a method is known from DE-A-416219. This document teaches an electromechanical encryption machine in which a rotor is used to encrypt or decrypt plain text. The rotor assigns exactly one other letter to the group from each letter from a group of letters For example, the letters b, a, d, e, c can be assigned to a group of five letters a, bc, d, e. By rotating the rotor, the assignment rule can be changed. For example, in the example above, the rotor is rotated one character, so the letters a, b, c, d, e are assigned the letters d, c, b, ea. In the original assignment, the difference between the plain text character and the encrypted character was +1, -1, +1, +1 and -2 After turning the rotor further, this difference amounts to -2, +1, -1, +1 and +1. It is evidently assumed that the letters are repeated cyclically so that the The first letter a follows the last letter According to Friedrich L Bauer "Deciphered Secrets", Springer Verlag, Berlin, 1995 it was suggested early to connect several rotors in a row. For example, the encryption machines "Enigma a" and "Enigma b", which are in the World War II, four rotors or "through-wheels" were used. Furthermore, it was proposed to use "key wheels" to put an irregular number of positions in front of the rotors after each encryption step. With four key wheels with periods of 17, 19, 21 and 23, the period is 17 x 19 x 21 x 23 (= 156O09) In the meantime, further algorithms have been developed for use in data processing systems. One of these methods is the RC4 algorithm. The RC4 algorithm is a symmetrical algorithm, which means that the same key is used for encryption and decryption. The RC4 algorithm processes a bit sequence and uses a key of variable length with up to 256 bits The RC4 algorithm uses a replacement key with 256 entries, whereby the entries include all numbers between 0 and 255 and the order is a function of the key From the replacement list, the key and the number of previously encrypted characters a random byte is determined which is linked to eight consecutive bits of the bit stream to be encrypted by an exclusive or operation. The RC4 algorithm is about 10 times faster than the DES algorithm described below

DES (data encryption standard) was standardized in 1977 by the National Bureau of Standards (NBS) in the USA (DES, National Bureau of Standards US Federal Information Processing Standards Publication 46, National Technical Information Service, Spπngfield, VA, April 1977) A block cipher for byte octograms A sequence of fixed transpositions and key-dependent multipartite, non-near substitutions ensures very thorough mixing.A key provided is 8 bytes long, including 8 parameter bits.An 8-byte plain text block is first subjected to a key-independent input permutation P and then in two 4 -Byte blocks divided by a left and a right Now 16 rounds follow, in which the left 4-byte block is equal to the right 4-byte block of the previous round and the right 4-byte block from the left 4-byte block of the previous round by adding modulo 2 with a function value, where the function value depends on the right 4-byte block of the previous round and a 48-bit round key for each round, the 48-bit round key is generated from the specified key. Finally, the inverse permutation to the input permutation is based on the 8-byte, that result after the 16 rounds An improved version of the DES is the TDEA (tπple data encryption algorithm see ANSI X 9 52). Each TDEA encryption or decryption is a composite operation of DES encryption and decryption. A TDEA encryption comprises DES encryption with a first key , DES decryption with a second key and a second DES decryption with a third key. The corresponding TDEA decryption includes DES decryption with the third key, DES decryption with the second key and DES decryption with the first Keys The three keys can be different, or the first can be the same as the third but different from the second key. If all three keys are the same, TDEA changes to DES

Another encryption algorithm is IDEA (US-A-5 214 703). IDEA is similar to DES. In contrast to DES, IDEA uses a total of nine levels of encryption, the first eight of which are the same. In addition, the 8-byte blocks into which the Plain text is divided into four sub-blocks. Sub-keys are generated from a key block, which preferably has a length of 128 bits. On each of the first eight encryption levels, four sub-blocks are linked with six sub-keys, so that four sub-blocks are obtained after each of these encryption levels

In "Descπption of a new variable-length key, 64-Bιt-Block Cipher (blowfish)" (Fast Software encryption, Cambridge secuπty Workshop proceedings (December 1993) Springer Verlag 1994, pages 191 to 204) G Schneider describes the requirements for one Encryption algorithm

Encryption algorithm must be implementable on a variety of different platforms, for example on application-specific integrated circuits (ASIC) and processors of different performance classes, The requirements for small processors are the most difficult to meet, since only little memory space is available in RAM and ROM. The algorithm should also be easy to use Different levels of security can be adjusted All computing operations should be done with 8 bit blocks or where possible with 32 bits should be carried out. The algorithm should include simple operations that are efficiently implemented in a large number of microprocessors, for example exclusive or addition. Lookup in a table and module calculation. Shifts of variable long bit-wise permutations or conditional jumps should not be used

In addition, this document describes the blowfish algorithm. The blowfish algorithm, like DES, divides the data to be encrypted into 64-bit blocks. In 16 rounds, a sub-algorithm similar to DES is carried out. The left and right 4-byte partial blocks are executed however linked differently with the round keys generated from the key and the function for calculating the right 4-byte part block does not depend on a round key but only on the left 4-bit part block

The object of the invention is to provide an encryption method, a decryption method and a data processing program and a computing device for carrying out the encryption and / or decryption method, which require little computing effort with regard to encryption and decryption and nevertheless have a high level of security

The object is achieved by an encryption method for encrypting a sequence of clear characters by means of a computing device, the method comprising the following initialization step providing a first one-dimensional memory field which comprises a multiplicity of memory cells, each memory cell being assigned a unique index and each memory cell taking on m different values , selection of a first index for selecting one of the memory cells and the method comprising the following encryption step, linking a clear character to be encrypted to the content of the memory cell associated with the selected first index to generate an encrypted character, varying the selected first index according to a step value, and repeating the Encryption layer with changing step value, the method comprising the following further initiation step Storing a standard value in a feedback memory as well as the following sub-steps within the encryption step comprises linking the content of the memory cell assigned to the selected first index to the content of the feedback memory using a first operator to generate a first intermediate result and using the first intermediate result for the link with the clear character , for generating the encrypted character, and linking the content of the feedback memory with the encrypted character using a second operator and storing the result in the feedback memory

The object is further achieved by an encryption method for encrypting a sequence of clear characters by means of a computing device, the method comprising the following initialization step providing a second one-dimensional memory field which comprises a plurality of memory cells, each memory cell being assigned a unique index and each memory cell m can take different values, selecting a second index for selecting one of the memory cells of the second one-dimensional memory array, and the method comprising the following encryption step linking a clear character to be encrypted to the content of the memory cell assigned to the selected second index to generate an encrypted character, selecting a new one second index, which is assigned to another, preferably the next memory cell of the second memory field, repeating the encryption step, the method The following further encryption step is carried out, which is carried out after the selection of the new second index, indirectly linking the content of the memory cell assigned to the new second index with the encrypted character and storing this result in the memory cell assigned to the new second index

Furthermore, the task is solved by a decryption method for decrypting a sequence of encrypted characters by means of a computing device, the method comprising the following initialization step providing a first one-dimensional memory field which contains a plurality of memory cells comprises where each memory cell is assigned a unique index and where each memory cell can have m different values, selecting a first index for selecting one of the memory cells and the method comprising the following decoding step linking an encrypted character to be decrypted to the content of the memory cell assigned to the selected first index for generating a clear character, varying the selected first index in accordance with a step value and repeating the decryption step with changing step value, the method comprising the following further initialization step, storing a start value in a feedback memory, and further sub-steps within the decision step comprising linking the content of the selected one to the first Index-associated memory cell with the content of the feedback memory using a first operator to generate a first Intermediate result and using the first intermediate result for linking with the encrypted character, for generating the clear character, and linking the content of the feedback memory with the encrypted character using a second operator and storing the result in the feedback memory

Furthermore, the object is achieved by a decryption method for decrypting a sequence of encrypted characters by means of a computing device, the method comprising the following initialization step providing a second one-dimensional memory field which comprises a multiplicity of memory cells, each memory cell being assigned a unique index and each memory cell being m different values can be selected by selecting a second index for selecting one of the memory cells of the second one-dimensional memory array, and the method comprises the following decision step: linking an encrypted character to the content of the memory cell associated with the selected second index to produce a clear character. selecting a new second index, the another is preferably assigned to the next memory cell of the second memory field, repeating the encryption step, the method following others Decryption step, which is carried out after the selection of the new second index, indirectly linking the content of the memory cell assigned to the new second index with the encrypted character and storing this result in the memory cell assigned to the new second index

In addition, the object is solved by the subject matter of claims 31, 32 and 33

Preferred developments of the invention are the subject of the dependent claims

It is particularly advantageous in the subject matter of the present invention that each encrypted character depends not only on the corresponding clear character but also on the preceding already encrypted characters. A feedback based on previous encrypted characters is better than a feedback based on previous clear characters because the encrypted characters Characters do not have speech patterns

Another advantage is that compared to known encryption and decryption methods with a much smaller number of transformations, the same high security level can be achieved. It is also advantageous that any key length can be used. The key length is only limited by the available storage space

Another particular advantage of the subject matter of claims 1 and 16 is that these methods require a very small RAM area, since the first one-dimensional memory array can be implemented as ROM. Advantageous of the subject matter of claims 3 and 18 is that no feedback memory F is required and the entire memory area can be smaller with the same security level

The advantage of an encryption method according to claim 2 or 4 and a decryption method according to claim 17 or 19 then prevails that Provision of a second one-dimensional memory field extended the period after which the same memory cells of the first one-dimensional memory field are used for the encryption in the same order. Assuming that the length of the first memory field S and the length of the second memory field C are prime, the period is longer than the product of the two long ones

A particular advantage of an encryption method according to claim 5 and a decryption method according to claim 20 is that the memory cells in the second one-dimensional memory field are changed in accordance with the content of the feedback memory F. Thus, these memory cells depend indirectly on the plaintext to be encrypted, assuming that the plaintext is not repeated , the period after which the same memory cells of the first memory field are reused for encryption in the same order is infinitely long

The additional memory fields in an encryption method according to claims 6, 7 and 8 and the decryption method according to claims 20, 21 and 22 mix speech patterns in plain text even better

An advantage of the cyclical rotation of the feedback memory F according to claims 1 1 and 26 is that the feedback operation comprises an unexpected and therefore difficult to analyze process step

An advantage of the encryption method according to claim 12 and of the decryption method according to claim 27 is that it can be implemented particularly effectively on powerful processors

An advantage of the encryption method according to claims 14 and 15 and the decryption method according to claims 29 and 30 is that, given a storage location, the period is one for a predetermined number of storage fields After maximum sicn receive the contents of the memory cells of the first memory field repeat

Preferred embodiments of the encryption method according to the invention and of the inventive method are described below

Declaration process explained in more detail with reference to the accompanying drawings

1 shows a schematic flow diagram to explain a preferred embodiment of the encryption method according to the invention and

2 shows a schematic flow diagram to explain a preferred embodiment of the decoding method according to the invention

A preferred embodiment of the invention comprises a total of four one-dimensional memory fields. The following designations are used for these memory fields

S first memory field

C second memory field

A third memory field

B fourth memory field

The first storage field S can be understood as a rotor or through wheel according to the Enigma machine mentioned above.The third and fourth storage fields A and B can be understood as key wheels for advancing the rotor or rotors.The second storage field C fulfills both the function of a key wheel and that of a rotor The length of a memory field, ie the number of memory cells in the memory field, is denoted by L (x). The variable x stands for A, B, C or S. According to the preferred embodiment, each memory cell in a memory field corresponds to one byte In addition to the four memory fields, the following variables are also used and are stored in memory cells

K index for the first memory field S (preferably 1 byte long)

Z index for the second memory field C (preferably 1 byte long)

X index for the third memory field A (preferably 1 byte long)

Y index for the fourth memory field B (preferably 1 byte long)

F jerk coupling buffer (preferably n bytes long)

T buffer (preferably n bytes long)

R amount of cyclic rotation in bits (0 to 31)

The size of the memory cells for the indexes X, Y, Z and K depends on the length of the memory fields. If the memory fields include fewer than 256 memory cells, one byte is sufficient for each index. With longer memory fields, more memory space must be made available for the indexes As explained further below, in the preferred embodiment, a block of n bytes of plain text or unencrypted source data is encrypted at once. In a particularly preferred embodiment, n = 4. The feedback memory F and the buffer store T have the same number of bytes n as the block that was encrypted at once From clear characters to For versions with less powerful processors, in which only one or two bytes of clear characters are encoded at one time, the size of the feedback memory F and the buffer memory T would also be only one or two bytes. For the memory R, a size of one byte equipment legal as long as the size of the block of characters that are encrypted or decrypted at one time is less than 32 bytes

Operators introduced in the following are referred to as ^OPv . In the preferred embodiment, y can assume the values 0 to 7 corresponding to eight different operators. An operator ^OPy preferably stands for addition (+) subtraction (-) or an exclusive or operation (XOR) operators that are the same

OPy

Number y should have the same value. The inverse operator to is with IQPY. The inverse operator to an addition is accordingly a subtraction and vice versa, and the XOR operator is the inverse operator to itself. Furthermore, the function ROTL (uv) rotates the bits of a memory cell v cyclically to the left by the number of u bits

The following designations are also used in the description of encryption and decryption in terms of formula

P clear character block (n bytes)

Q block of encrypted characters (n bytes)

S (i) n successive memory cells of the first memory field starting with index i (n bytes)

C (i) n consecutive bytes of the memory field C starting with index i (n bytes)

A (i) n successive memory cells of the third memory field A starting with index i (n bytes)

B (i) n successive memory cells of the fourth memory field B starting with index i (n bytes)

The designations P, QS (i), C (i) A (i) and B (i) refer to memory areas of the same size. According to a preferred embodiment, a block of four bytes is encrypted or decrypted at a time. In this case, the Designations S (i), C (ι), A (i) and B (i) also on memory sections of the large four bytes. Since each memory cell in the four memory fields S, CA and B corresponds to one byte, four memory cells are combined

The following arithmetic operations are carried out for the encryption of a block of n clear characters

TA (X) ^OP0 B (Y) K = (KO ^u P1 ^, T) mod (L (S) -n + 1) Q = P ^OP2 (C (Z) ^OP3 F ^OP4 S (K) ^OP5 T) F = ROTL (R, (F ^OP6 Q))

X = (X + 1) mod (L (A) -n + 1)

Y = (Y + 1) mod (L (B) -n + 1)

Z = (Z + 1) mod (L (C) -n + 1)

C (Z) = C (Z) ^OP7 F

The following equations are used to decrypt a block of π encrypted characters

T = A (X) ^OP0 B (Y)

K = (K ^op1 T) mod (L (S) -n + 1)

P = QÖP2 (C (Z) ^OP3 F ^OP4 S (K) ^OP5 T)

F = ROTL (R, (F ^OP6 Q))

X = (X + 1) mod (L (A) -n + 1)

Y = (Y + 1) mod (L (B) -n + 1) z = (Z + 1) mod (L (C) -n + 1)

C (Z) = C (Z) ^OP7 F

The encryption operations and the decryption operations differ only in that P and Q are interchanged in the third equation and the operator ^{OP2 is used} for encryption, whereas the inverse operator ^ is used for decryption. In one embodiment, an XOR is used for the operator ^OP2. If the operator is used, the same method can be used for the encryption as for the decryption, since the XOR operator is also its inverse operator

When initializing the indexes, it is preferably ensured that the indexes are in the following range

K 0 (L (S) -n)

Z 0 (L (C) -n)

X 0 (L (A) -n) Y 0 (L (B) - n)

(L (x) -π) is the so-called last possible index, where x stands for S, C A or B.

The nature of this encryption and decryption process depends on the content, i.e. the key is changed dynamically during encryption and decryption. It is not possible to decrypt part of the data without knowing the immediately preceding data of this part

The lengths of the memory fields S, C, A and B should be chosen so that they are prime to each other, so that there is as long a period as possible after which the same values of the memory fields C and S are repeated. Such a repetition is due to the feedback via the Feedback memory F and via memory field C, however, is only possible if the text to be encrypted is also repeated periodically. The period defined by memory fields S, C, A and B occurs with the encrypted characters if the same clear character, for example, is always used for test purposes a zero, is encrypted Due to the feedback, the period does not result directly as the smallest common multiple of the memory field lengths, but is significantly longer than this smallest common multiple, even if the same clear character is always encrypted In order to obtain the largest possible period, the length of the four Storage fields S, C, A and B not only te iler foreign, but should also be approximately the same size So the length of the memory fields A and B should preferably differ by only one. In the preferred embodiment, the lengths of the memory fields S, C, A and B become 11, 5, 8 and 7 in this Order selected

According to a preferred embodiment, additions are performed for the OPO, OP1, OP2 and OP5 operators, XOR operations for the OP3 and OP6 operators and subtractions for the OP4 and OP7 operators

For experimental purposes, a large file of four megabytes was encrypted, which contained only zeros. The result was a uniform distribution of the Byte values for all scnuses Furthermore, there was a similarly uniform distribution for word values (two bytes). The key length did not affect the distribution. The encrypted data could not be compressed by LZW CIP or BZIP2 algorithms, which means that there were no patterns in a practically usable area Implementation of the preferred embodiment in unoptimized C code was about 10% faster than an optimized assembler version of the RC4 encryption method. The RC4 encryption method is the fastest encryption method available on the market

An important point concerns the optimized use of keys. The key should be changed from time to time. From the key, the initial values of the memory fields S, C, A and B, the indices K, Z, X and Y of the feedback memory F and the rotation value R can be changed In general, a key will not be long enough to fill all of these memories. In this case, the key is repeated cyclically until all memory fields are filled. In another embodiment, the key only defines the indices K, Z, X and Y, whereas the contents of the memory cells of the memory fields S, C, A and B remain unchanged. According to a further embodiment, the key is used to select the initialization from a predetermined set of initializations for the memory fields S, C, A and B, the quantity of Initializations do not contain "weak initializations", when used an En Encryption is particularly simple, for example because one or more memory fields are only initialized with zeros. The advantage of such a variant is that "weak initializations" can be excluded in a simple manner. According to further embodiments, the above methods can also be mixed, so that, for example, by the key one of four possible initializations for the memory fields A and B is selected, whereas the initialization of the memory fields S and C and the indices follows by the rest of the key According to preferred embodiments, the memory fields are further initialized such that the content of the last n memory cells is equal to the content of the first n memory cells of each memory field. Here n is the number of clear characters encrypted in a block. Advantageous in these preferred embodiments is that no patterns occur during encryption The different frequency of use of certain memory cells arises. Assuming that each permissible index is used with the same frequency in a memory field, the first and last memory cells are accessed less frequently, for example, than a middle memory cell. Because the last n memory cells have the same values As the first n memory cells have, the memory cells are nevertheless accessed with different frequencies, but the (different) contents of the memory cells are nevertheless used with the same frequency

According to a further embodiment, the contents of the memory cells of the memory fields are selected independently of one another. An advantage of this embodiment is that the period when the same clear characters are encrypted is a function of the smallest common multiple of the lengths of the memory fields and not a function of the smallest common multiple of the last possible Indices and therefore longer

1 and 2 graphically illustrate a preferred encryption or decryption of a character block according to the present invention. The top and bottom lines of rounded rectangles contain the names of the memory cells, the content of which changes during an encryption or decryption step. These include the four indices from X, Y, Z and K, the memory field C and the feedback memory F A block of clear characters P is converted into a block of encrypted characters Q by the encryption section shown in FIG. 1. Conversely, a block is converted from a block of encrypted characters Q in the decryption section shown in FIG calculated by clear character P.

Operators are shown in a diamond ^{shape in} FIGS. 1 and 2. The operators ^opo to OP7 each require two input values and produce an output value Die Incremental operators +1 and the modulo operators mod (LA) mod (LB) mod (LC) mod (LS) generate an output value from an input value. The abbreviations LA LB LC and LS stand for the terms [L (A) -n + 1] [L (B) -n + 1], [L (C) - n + 1] and [L (S) -n + 1] The field operators A (X), B (Y) and S (K) were also Represented as operators with an input value and an output value, since the corresponding memory fields remain unchanged during encryption and decryption. For field operator C (Z), the notation is not uniform for reasons of space.This operator takes two input values, namely the index Z and the memory field C. and generates an output value. Also the inverse operator

| C (Z) | requires two input parameters, namely the index Z and the value to be written into the memory cell with the index Z of the memory field C.

Claims

claims

Encryption method for encrypting a sequence of clear characters using a computing device,

the method comprising the following initialization step

Providing a first one-dimensional memory field (S) which comprises a plurality of memory cells, each memory cell being assigned a unique index and each memory cell being able to assume m different values,

Selecting a first index (K) for selecting one of the memory cells,

and wherein the method comprises the following encryption layer

Linking a clear character to be encrypted (P) with the content of the memory cell (S (K)) assigned to the selected first index (K) to generate an encrypted character (Q),

Varying the selected first index (K) according to a step value, and

Repeating the encryption step with changing step value,

characterized by the following further initialization step

Storing a start value in a feedback memory (F),

as well as the following sub-steps within the crypt 13

Linking the content of the memory cell (S (K)) assigned to the selected first index (K) with the content of the feedback memory (F) using a first operator (OP4) to generate a first intermediate result and using the first intermediate result for linking to the Clear characters (P) for generating the encrypted character (Q) and

Linking the content of the feedback memory (F) with the encrypted character (Q) using a second operator (OP6) and storing the result in the feedback memory (F)

Encryption method according to claim 1, characterized in that the following further initialization section is provided

Providing a second one-dimensional memory array (C) which comprises a plurality of memory cells, each memory cell being assigned a unique index (Z) and wherein each memory cell can have m different values, and

Selection of a second index (Z) which is assigned to a memory cell (C (Z)) from the second memory field (C)

and the method comprises the following further encryption steps

Linking the content of the memory cell (C (Z)) assigned to the selected second index (Z) with the content of the feedback memory (F) using a third operator (OP3) and further linking this result to the first intermediate result and Selection of a new second index (Z) which is assigned to another, preferably the next memory cell of the second memory field (C)

the method comprising the following initialization step

Providing a second one-dimensional memory field (C) which comprises a plurality of memory cells, each memory cell being assigned a unique index and each memory cell being able to assume m different values,

Selection of a second index (Z) for selecting one of the memory cells of the second one-dimensional memory array,

and the method comprises the following encryption steps

Linking a clear character to be encrypted (P) with the content of the memory cell (C (Z)) assigned to the selected second index (Z) to generate an encrypted character (Q),

Selection of a new second index (Z) which is assigned to another, preferably the next memory cell of the second memory field (C),

Repeating the encryption steps,

characterized by the following further encryption step, which is carried out after the selection of the new second index (Z) indirectly linking the content of the memory cell assigned to the new second index (Z) with the encrypted character (Q) and storing this result in the memory cell (C (Z)) assigned to the new second index (Z))

Encryption method according to claim 3, characterized in that the following further initialization section is provided

Selecting a first index (K) for selecting one of the memory cells,

Storing a start value in a feedback memory (F),

and the method comprises the following further encryption steps

Varying the selected first index (K) according to a step value that changes from repetition to repetition of the encryption steps,

Linking the content of the memory cell assigned to the selected second index (Z) with the content of the feedback memory (F) using a third operator (OP3) to generate a second intermediate result,

Linking the second intermediate result with the content of the memory cell (S (K)) assigned to the selected first index (K) using a first operator (OP4) to generate a first intermediate result and using the first intermediate result for linking with the clear character (P) to generate the encrypted character (Q) and

Encryption method according to claim 2 or 4, characterized in that the method comprises the following further encryption step

Linking the content of the memory cell assigned to the selected second index (Z) with the content of the feedback memory (F) using a fourth operator (OP7) and writing the result in the memory cell assigned to the second index (Z) (C (Z))

Encryption method according to one of Claims 1 to 5, characterized in that the method comprises the following further initialization step

Providing a third one-dimensional memory array (A) comprising a plurality of memory cells, each memory cell being assigned a unique index (X), and

Selection of a third index (X) which is assigned to a memory cell of the third memory field (A), and wherein

the step value depends on the content of the memory cell assigned to the selected third index (X), and the method comprises the following further encryption step Selection of a new third index (X) which is preferably assigned to another of the next memory cell of the third memory field (A)

Encryption method according to claim 6, characterized in that the method comprises the following initialization step

Providing a fourth one-dimensional memory array (B) comprising a plurality of memory cells, each memory cell being assigned a unique index (Y), and

Selection of a fourth index (Y) which is assigned to a memory cell of the fourth memory field (B), and wherein

the step value depends on the content of the memory cell (B (Y)) assigned to the selected fourth index (Y) and the method comprises the following further encryption step

Selection of a new fourth index (Y) which is preferably assigned to another of the next memory cell of the fourth memory field (B)

Encryption method according to claim 7, characterized in that the method comprises the following further encryption steps

Linking the content of the memory cell assigned to the selected fourth index (Y) with the content of the memory cell assigned to the selected third index (A (K)) using a fifth operator (OP0) to obtain a third intermediate result (T), Combining the value α of the selected first index (K) with the second intermediate result (T) using a sixth operator (OP1) to obtain a fourth intermediate result, and

Selection of a new first index (K) according to the fourth interim result mod (1 + largest approved first index (K))

Encryption method according to claim 8, characterized in that the method comprises the following further encryption steps

Linking the first intermediate result with the third intermediate result (T) using a seventh operator (OP5) and

Link this result with the clear character (P) by an eighth operator (OP2) in order to obtain the encrypted character (Q)

Encryption method according to one of Claims 1 to 9, characterized in that all memory cells correspond to one byte and all other memories comprise a sequence of bits

Encryption method according to claim 10, characterized in that the method comprises the following further encryption step

cyclically rotating the bits in the feedback memory (F) a predetermined number of bits to the left

Encryption method according to one of claims 1 to 11, characterized in that in the sequence of clear characters, a predetermined number of n successive clear characters is processed simultaneously as an operand, with (n-1) after the last possible memory cell Memory cells are available in each memory field, a sequence of n successive memory cells from each memory field being used as an operand for the linkage with the n successive clear characters or with n successive cells of other memory fields

Encryption method according to Claims 1 to 9, characterized in that the fifth sixth, seventh and eighth operator are addition operators, the second and third operator are exclusive-OR operators and the first and fourth operator are subtraction operators

Encryption method according to one of claims 2 or 4 to 13, characterized in that the numbers of the memory cells of two memory fields are prime to each other

Encryption method according to one of Claims 2 or 4 to 13, characterized in that the numbers of the memory cells in front of the maximum possible memory cell, including the maximum possible memory cell, are each relatively prime

Decryption method for decrypting a sequence of encrypted characters by means of a computing device,

the method comprising the following initialization step

Selecting a first index (K) for selecting one of the memory cells, and the method comprises the following decryption steps

Linking an encrypted character (Q) to be decrypted with the content of the memory cell (S (K)) assigned to the selected first index (K) to generate a clear character (P),

Varying the selected first index (K) according to a step value and

Repeating the decision steps with changing step value,

characterized by the following further initiation step

Storing a start value in a feedback memory (F),

as well as the following sub-steps within the decision-making steps

Linking the content of the memory cell (S (K)) associated with the selected first index (K) with the content of the feedback memory (F) using a first operator (OP4) to generate a first intermediate result and using the first intermediate result for linking with the encrypted character (Q) to generate the clear character (P), and

Decryption method according to claim 16, characterized in that it further comprises the following initialization section Providing a second one-dimensional memory array (C) which comprises a plurality of memory cells, each memory cell being assigned a unique index (Z) and wherein each memory cell can have m different values, and

Selection of a second index (Z) which is assigned to a memory cell (C (Z)) from the second memory field (C),

and the method comprises the following further decryption steps

Linking the content of the memory cell (C (Z)) assigned to the second selected index (Z) with the content of the feedback memory (F) using a third operator (OP3) and further linking this result to the first intermediate result, and

Selection of a new second index (Z) which is assigned to another, preferably the next memory cell of the second memory field (C)

the method comprising the following initialization step

Selection of a second index (Z) for selecting one of the memory cells of the second one-dimensional memory array and the method comprises the following decryption steps

Linking an encrypted character (Q) with the content of the memory cell (C (Z)) assigned to the selected second index (Z) to generate a clear character (P),

Repeating the decision steps,

characterized by the following further decision-making step which is carried out after the selection of the new second index (Z)

indirectly linking the content of the memory cell assigned to the new second index (Z) with the encrypted character (Q) and storing this result in the memory cell (C (Z)) assigned to the new second index (Z))

Decoding method according to claim 18, characterized in that the following further initialization section is provided

Selecting a first index (K) for selecting one of the memory cells,

Storing a start value in a feedback memory (F), 23

and the method comprises the following further decryption steps

Linking the second intermediate result with the content of the memory cell (S (K)) assigned to the selected first index (K) using a first operator (OP4) to generate a first intermediate result and using the first intermediate result for linking with the encrypted character (Q ), to generate the clear character (P) and

Decryption method according to claim 17 or 19, characterized in that the method comprises the following further decryption step

Linking the content of the memory cell assigned to the selected second index (Z) with the content of the feedback memory (F) using a fourth operator (OP7) and writing the Result in the memory cell (C (Z)) assigned to the second index (Z)

Decoding method according to one of Claims 16 to 20, characterized in that the method comprises the following further initialization step

the step value depends on the content of the memory cell assigned to the selected third index (X), and the method comprises the following further decision step

Selection of a new third index (X) which is assigned to another, preferably the next memory cell of the third memory field (A)

Decryption method according to claim 21, characterized in that the method comprises the following initialization step

Providing a fourth one-dimensional memory array (B) which comprises a plurality of memory cells, each memory cell being assigned a unique index (Y), and

Selection of a fourth index (Y) which is assigned to a memory cell of the fourth memory field (B), and wherein the step value depends on the content of the memory cell (B (Y)) assigned to the selected fourth index (Y) and the method comprises the following further decision step

Selection of a new fourth index (Y) which is assigned to another, preferably the next memory cell of the fourth memory field (B)

Decryption method according to claim 22, characterized in that the method comprises the following further decryption steps

Link the content of the memory cell assigned to the selected fourth index (Y) with the content of the memory cell assigned to the third index (A (K)) using a fifth operator (OPO) to obtain a third intermediate result (T)

Combining the value of the first index (K) with the second intermediate result (T) using a sixth operator (OP1) to obtain a fourth intermediate result, and

Selection of a new first index (K) corresponding to the fourth buffer result mod (1 + largest approved first index (K))

Decryption method according to claim 23, characterized in that the method comprises the following further decryption steps

Linking the first intermediate result with the third intermediate result (T) using a seventh operator (OP (5)) and Link this result to the encrypted character (Q) by an eighth operator (θP2 |) to get the clear character (P)

Decryption method according to one of Claims 16 to 24, characterized in that all memory cells correspond to one byte and all other memories comprise a sequence of bits

Decryption method according to claim 25, characterized in that the method comprises the following further decryption step

Decryption method according to one of Claims 16 to 26, characterized in that, in the sequence of encrypted characters, a predetermined number of π consecutive encrypted characters are processed simultaneously as one operand, with (n-1) memory cells in each memory field after the last possible memory cell are available, a sequence of n consecutive memory cells from each memory field being used as an operand for the linkage with the n consecutive encrypted characters or with n consecutive cells of other memory fields

Decryption method according to claims 16 to 24, characterized in that the fifth, sixth, seventh and eighth operator are addition operators, the second and third operator are exclusive or operators and the first and fourth operator are subtraction operators

Decoding method according to one of claims 17 or 19 to 28, characterized in that the numbers of the memory cells are two prime to each other Decoding method according to one of Claims 17 or 19 to 28, characterized in that the numbers of the memory cells in front of the maximum possible memory cell, including the maximum possible memory cell, are each prime to two

Data processing program, preferably in a form stored on a data carrier, for carrying out an encryption process according to one of claims 1 to 15 and / or for carrying out a decryption process according to one of claims 16 to 30

Encryption device with a memory device and a computing device for carrying out the method according to one of claims 1-15

Decryption device with a memory device and a computing device for carrying out the method according to one of Claims 16-30