mirror of
https://codeberg.org/scip/twenty4.git
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new version using combined PRNGs seeded with 160bit key as key stream
This commit is contained in:
TLINDEN
75
README.md
75
README.md
@@ -1,11 +1,12 @@
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## TWENTY4 - a fun stream cipher
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## TWENTY4/160 - a fun stream cipher
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*THIS IS JUST FOR LEARINING CRYPTO, DO NOT EVER USE THIS FOR ANYTHING*
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This is the implementation of the fun stream cipher TWENTY4 by T.v. Dein, 09/2015.
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This is the implementation of the fun stream cipher TWENTY4/160 by T.v. Dein, 09/2015.
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Published under the public domain, Creative Commons Zero License. It works bytewise,
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with keys between 1-256 bits in 17 rounds, uses S-Boxes and key output-feedback mode.
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The cipher also works with CBC or ECB mode (sample CBC implementation included).
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uses a 160 bit key bits in 8 rounds, applies an S-Box. From the key various PRNGs
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are seeded, all those PRNGs are recombined into an output key stream, which is being
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xored with the input (after applying of the sbox).
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The name TWENTY4 is a reference to article 20 paragraph 4 of the german constitution
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which reads:
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@@ -14,7 +15,7 @@ which reads:
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> abolish this constitutional order, if no other remedy is available.
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Also, the cipher uses the contents of the german constitution as the source for its
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S-Boxes.
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S-Box.
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## S-Box generation
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@@ -54,72 +55,16 @@ TWENTY4 uses two S-Box arrays, one for key expansion and one for encryption.
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## Key expansion
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The input key will be expanded into a 32 byte array. Maximum key size is
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32 bytes (256 bit).
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IV = KU[0]
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for ROUND in 0..31
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if KU[ROUND]
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K[ROUND] = IV xor KU[ROUND]
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else
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K[ROUND] = IV yor KBOX[ROUND * 8];
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endif
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K[ROUND] = KBOX[K[ROUND]]
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IV = K[ROUND]
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endfor
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for KROUND in 0..31
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for ROUND in 0..31
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K[ROUND] = IV xor (rotateleft(K[ROUND], 3) xor KBOX[rcon(IV)])
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IV = K[ROUND]
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endfor
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endfor
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where:
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KU: input key
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K[17]: initial round key array
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ROUND: encryption round 1-32
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KROUND: key expansion round 1-32
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KBOX[256]: pre computed S-Box for key expansion
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FIXME.
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## Encryption
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for INBYTE in <INSTREAM>
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OUTBYTE = INBYTE
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for ROUND in 0..17
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OUTBYTE = OUTBYTE xor K[ROUND]
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OUTBYTE = OUTBYTE xor SBOX[OUTBYTE]
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OUTBYTE = rotateleft(OUTBYTE, ROUND mod 8)
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OUTBYTE = rotateright(K[ROUND], 4)
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endfor
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rotatekey(K, OUTBYTE)
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OUTBYTE => <OUTSTREAM>
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endfor
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func rotatekey(K, B)
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PREV = K[31]
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for N in 0..31
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NEXT = K[N]
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K[N] = PREV
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PREV = NEXT
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K[N] = KBOX[K[N] xor B]
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endfor
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endfunc
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where:
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K[17]: expanded key
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ROUND: encryption round 1-17
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INBYTE: one input byte
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OUTBYTE: encrypted result for output
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SBOX[256]: pre computed S-Box for encryption
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rotateleft(B,N): rotate byte B by N bits to the left
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rotateright(B,N): rotate byte B by N bits to the right
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FIXME.
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## Analysis so far
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These are the results of the previous (128bit) version.
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While this stuff only exists for me to play around with
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crypto, I tried to test the cipher a little bit. Here are
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my results using a couple of statistical measurements:
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380
twenty4.c
380
twenty4.c
@@ -1,44 +1,33 @@
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/*
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******* THIS IS JUST FOR LEARINING CRYPTO, DO NOT EVER USE THIS FOR ANYTHING *******
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This is the implementation of the fun stream cipher TWENTY4 by Thomas von Dein, 09/2015.
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This is the implementation of the fun stream cipher TWENTY4/160 by Thomas von Dein, 09/2015.
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Published under the public domain, Creative Commons Zero License.
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*/
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#include <stdio.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include <unistd.h>
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#include <inttypes.h>
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#include <string.h>
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#include <ctype.h>
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#include <math.h>
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typedef uint8_t byte;
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typedef uint32_t word;
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typedef uint16_t half;
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typedef uint32_t u32;
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typedef uint64_t u64;
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const byte kbox[] = {
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0x53, 0x61, 0x6c, 0x74, 0x65, 0x64, 0x5f, 0xdf, 0x40, 0xc1, 0x9d, 0x46, 0x33, 0x45, 0x92, 0x95,
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0xd8, 0x24, 0xf5, 0x1c, 0xe0, 0x29, 0xff, 0xa3, 0x71, 0x6f, 0x35, 0x2e, 0x4b, 0x0d, 0xa7, 0x5d,
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0x97, 0xe1, 0x98, 0x58, 0x2b, 0xc4, 0xae, 0xe3, 0xec, 0xb8, 0x38, 0xee, 0x91, 0x2c, 0xb4, 0xa0,
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0xc6, 0x34, 0x1f, 0x57, 0x0e, 0xc3, 0x4f, 0xb9, 0x80, 0x21, 0x5b, 0x06, 0xf6, 0x87, 0xfa, 0x5e,
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0xe7, 0xda, 0xce, 0xdd, 0x23, 0xe9, 0x03, 0x39, 0xa5, 0x8e, 0xb6, 0xca, 0x3c, 0x7a, 0x44, 0x2d,
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0x07, 0xcf, 0x1b, 0xd0, 0x94, 0x85, 0xc5, 0x20, 0xaa, 0x81, 0xc9, 0xb7, 0x2f, 0xfb, 0xb2, 0x50,
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0x54, 0xf0, 0x14, 0xd9, 0x00, 0x67, 0x15, 0x9f, 0xa2, 0x02, 0x93, 0xcc, 0xdb, 0x8d, 0x30, 0x78,
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0xb1, 0x7b, 0x19, 0xc0, 0x43, 0x6b, 0xbb, 0x2a, 0x3b, 0x4d, 0xe4, 0x08, 0x12, 0x90, 0x32, 0xef,
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0xe8, 0x5a, 0xac, 0xf4, 0x8c, 0xe2, 0x4e, 0x6d, 0xaf, 0x66, 0xf8, 0xbc, 0x36, 0x72, 0x01, 0x1e,
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0x68, 0x37, 0x59, 0x51, 0xa6, 0x7c, 0xbe, 0x86, 0x8a, 0x8b, 0xfe, 0x0a, 0x05, 0x52, 0x76, 0x27,
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0x69, 0x18, 0x22, 0x63, 0x42, 0x4a, 0xad, 0x10, 0xe5, 0xa1, 0xc8, 0xeb, 0xb0, 0x09, 0x6a, 0x4c,
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0x16, 0xf7, 0xde, 0xfc, 0x7f, 0x7d, 0xdc, 0x99, 0xbd, 0x7e, 0x26, 0xcd, 0xba, 0xc2, 0xa8, 0x04,
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0x0f, 0x3e, 0x82, 0x1d, 0x89, 0xb5, 0x31, 0xb3, 0x47, 0x6e, 0xf3, 0x0b, 0xd3, 0x84, 0x49, 0x0c,
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0x3d, 0xd5, 0x9a, 0xd6, 0x9e, 0xd7, 0x8f, 0xa9, 0x79, 0xd4, 0x48, 0x9b, 0x55, 0x56, 0xcb, 0x3a,
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0xf9, 0xfd, 0xd2, 0xe6, 0x75, 0x1a, 0x11, 0xf2, 0xa4, 0x5c, 0x96, 0x13, 0xea, 0xd1, 0xbf, 0x60,
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0x28, 0xab, 0x9c, 0x77, 0x83, 0x62, 0x17, 0x41, 0x70, 0x25, 0xf1, 0x3f, 0x88, 0x73, 0xc7, 0xed,
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/* global context, stores the 160 bit key */
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struct _ctx {
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u32 lcg;
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u32 d1u;
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u32 decide;
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u64 shift;
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};
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typedef struct _ctx ctx;
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ctx *context;
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const byte sbox[] = {
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/* sbox used for i/o stream diffusion */
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const uint8_t sbox[] = {
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0x61, 0x2d, 0x19, 0xf3, 0xe5, 0xd9, 0xde, 0x5f, 0x41, 0x31, 0xa7, 0xc2, 0x48, 0x02, 0xef, 0x98,
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0x67, 0xcb, 0x6e, 0x4c, 0xf4, 0x11, 0xfa, 0x87, 0x0f, 0x6f, 0x0a, 0x3b, 0x71, 0x09, 0x1a, 0xb8,
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0x3c, 0x44, 0xd8, 0xd4, 0xc8, 0x91, 0x6d, 0x8c, 0x2f, 0xce, 0x85, 0x22, 0xd5, 0x08, 0xa6, 0x97,
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@@ -55,256 +44,195 @@ const byte sbox[] = {
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0xab, 0xfc, 0xc4, 0x1d, 0x6a, 0x6c, 0x3f, 0x9b, 0x9a, 0x51, 0xa2, 0x86, 0x52, 0x4a, 0x43, 0x14,
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0x75, 0xff, 0xf5, 0xcd, 0x1b, 0x0d, 0x35, 0x24, 0x9c, 0xe1, 0x60, 0x73, 0x3e, 0x39, 0x53, 0x16,
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0x50, 0x6b, 0xc9, 0x46, 0x57, 0x5c, 0x69, 0x79, 0x82, 0xf1, 0x27, 0x38, 0x34, 0xf6, 0x00, 0xa9,
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};
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byte revsbox[256];
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#define K_HASH_ROUNDS 32
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#define S_BOX_ROUNDS 17
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byte rot8left(byte in, int rot) {
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return (in >> (8-rot)) | (in << rot);
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/* convert a 64bit number into an 8 element byte array */
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void w2a(u64 in, uint8_t *out) {
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out[0] = (in >> 56) & 0xFF;
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out[1] = (in >> 48) & 0xFF;
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out[2] = (in >> 40) & 0xFF;
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out[3] = (in >> 32) & 0xFF;
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out[4] = (in >> 24) & 0xFF;
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out[5] = (in >> 16) & 0xFF;
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out[6] = (in >> 8) & 0xFF;
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out[7] = in & 0xFF;
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}
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byte rot8right(byte in, int rot) {
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return (in << (8-rot)) | (in >> rot);
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/* rotate 64bit number by 'rot' left */
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u64 rot64left(u64 in, int rot) {
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if(rot == 0) rot = 1;
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return (in >> (64-rot)) | (in << rot);
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}
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void printbits(byte v) {
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int i;
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for(i = 7; i >= 0; i--) fprintf(stderr, "%c", '0' + ((v >> i) & 1));
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/* rotate 32bit number by 'rot' left */
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u32 rot32left(u32 in, int rot) {
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return (in >> (32-rot)) | (in << rot);
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}
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void dump8(char *n, byte d) {
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fprintf(stderr, "%s: %02x ", n, d);
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printbits(d);
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fprintf(stderr, "\n");
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/* park-miller 32bit prng */
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u32 _32_lcg_pm(u32 seed) {
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return ((u64)seed * 48271UL) % 2147483647UL;
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}
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void dumpN(char *n, byte *d, size_t s) {
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int l = strlen(n) + 9;
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fprintf(stderr, "%s (%04ld): ", n, s);
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size_t i;
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int c;
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for (i=0; i<s; ++i) {
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fprintf(stderr, "%02x ", d[i]);
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if(i % 8 == 7 && i > 0) {
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fprintf(stderr, "\n");
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for(c=0; c<l; ++c)
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fprintf(stderr, " ");
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}
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}
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fprintf(stderr, "\n");
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/* galois 32bit linear feedback shift register, taps: 32 31 29 1 */
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u32 _32_gal_d1u(u32 seed) {
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return (seed >> 1) ^ (unsigned int)(0 - ((seed & 1u) & 0xd0000001u));
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}
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/* for decryption */
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void reverse_sbox() {
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int i;
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for(i=0; i<256; i++)
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revsbox[sbox[i]] = i;
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/* de-buijn 32bit non-linear feedback shift register */
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u32 _32_nlfsr_debuijn(u32 seed) {
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int k = 28, n = 31;
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return ((((seed>>k)^seed^!(seed>>1))&1)<<(n-1))|(seed>>1);
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}
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byte getiv() {
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FILE *RAND;
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byte rand;
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if((RAND = fopen("/dev/urandom", "rb")) == NULL) {
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perror("Could not open /dev/urandom");
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exit(1);
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}
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if(fread(&rand, 1, 1, RAND) != 1) {
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perror("Could not read from /dev/urandom");
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exit(1);
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}
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fclose(RAND);
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return rand;
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/* 64bit non-linear xorshift register */
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u64 _64_xs_st() {
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context->shift ^= context->shift >> 12; // a
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context->shift ^= context->shift << 25; // b
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context->shift ^= context->shift >> 27; // c
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return context->shift * UINT64_C(2685821657736338717);
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}
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byte rcon(byte in) {
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byte c=1;
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if(in == 0)
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return 0;
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while(in != 1) {
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byte b;
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b = c & 0x80;
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c <<= 1;
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if(b == 0x80) {
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c ^= 0x1b;
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}
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in--;
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}
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return c;
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/* run registers/prng's */
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u64 fwd_prngs() {
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context->lcg = _32_lcg_pm(context->lcg);
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context->d1u = _32_gal_d1u(context->d1u);
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context->decide = _32_nlfsr_debuijn(context->decide);
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return _64_xs_st();
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}
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/* we use rounds * 8bit sub keys expanded from
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given password */
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void keyhash(char *pw, byte *hash) {
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byte iv;
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int i, round;
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unsigned int HEX;
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size_t pwlen;
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/* combine the different prng's into a 64bit round key */
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u64 combined64a() {
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u32 _x;
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u64 use, xorshift;
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int xSwap, xRot, xRotBy;
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if(strncmp(pw, "0x", 2) == 0) {
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/* hex pw */
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sscanf(pw, "0x%02x", &HEX);
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pw[0] = (byte)HEX;
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pwlen = 1;
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xSwap = 11; /* Sofie Germain primes as well */
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xRot = 29;
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xRotBy = 53;
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xorshift = fwd_prngs();
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if(context->decide % 2 == 0) {
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/* xor 64bit register with multiplied 32bit registers */
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use = xorshift ^ ((u64)context->lcg * (u64)context->d1u);
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}
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else {
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pwlen = strlen(pw);
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/* xor both 32bit registers (shifted into a 64bit) with 64bit register */
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use = xorshift ^ (((u64)context->lcg << 32) + context->d1u);
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}
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iv = kbox[(byte)pw[0]];
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/* stretch pw */
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for(i=0; i<K_HASH_ROUNDS; i++) {
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if((size_t)i < pwlen)
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hash[i] = iv ^ pw[i];
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else
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hash[i] = iv ^ kbox[i*8];
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hash[i] = kbox[hash[i]];
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iv = hash[i];
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if((context->decide & 0xFF) % xSwap == 0) {
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/* re-seed 32bit registers by swapping them */
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_x = context->lcg;
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context->lcg = context->d1u;
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context->d1u = _x;
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}
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/* diffuse and confuse hash */
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for(round=0; round<K_HASH_ROUNDS; round++) {
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for(i=0; i<K_HASH_ROUNDS; i++) {
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hash[i] = iv ^ ((rot8left(hash[i], 3) * kbox[rcon(iv)])) % 255;
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iv = hash[i];
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}
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if((context->decide & 0xFF) % xRot == 0) {
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// rotate 64t left
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context->shift = rot64left(context->shift, (context->decide & 0xFF) % xRotBy);
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}
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return use;
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}
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void reverse(byte a[], int sz) {
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int i, j;
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for (i = 0, j = sz; i < j; i++, j--) {
|
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byte tmp = a[i];
|
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a[i] = a[j];
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a[j] = tmp;
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}
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void dumpk(ctx *k) {
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fprintf(stderr, " lcg: %04X\n", k->lcg);
|
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fprintf(stderr, " d1u: %04X\n", k->d1u);
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fprintf(stderr, " decide: %04X\n", k->decide);
|
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fprintf(stderr, " shift: %" PRIX64 "\n", k->shift);
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}
|
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|
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void rotate(byte array[], int size, int amt) {
|
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if (amt < 0)
|
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amt = size + amt;
|
||||
reverse(array, size-amt-1);
|
||||
reverse(array+size-amt, amt-1);
|
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reverse(array, size-1);
|
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}
|
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/* convert 20 byte hex string into 160 bit key (= context) */
|
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ctx *parseargs(char *arg) {
|
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char tmp[9];
|
||||
size_t len;
|
||||
ctx *k;
|
||||
|
||||
void rotatekey(byte *key, byte feedback) {
|
||||
int i;
|
||||
byte f = key[0];
|
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len = strlen(arg);
|
||||
|
||||
for (i = S_BOX_ROUNDS-1; i>1; i--)
|
||||
key[i-1] = kbox[key[i] ^ feedback];
|
||||
|
||||
key[16] = kbox[f ^ feedback];
|
||||
}
|
||||
|
||||
/* actual stream cipher:
|
||||
- xor with round key
|
||||
- apply sbox
|
||||
- rotate left by (round mod 8) bits
|
||||
- xor with (round key rotated left by 4 bits [halfes reversed])
|
||||
*/
|
||||
byte bytebox(byte in, byte *key, int encrypt) {
|
||||
int i;
|
||||
byte out = in;
|
||||
|
||||
if(encrypt) {
|
||||
for(i=0; i<S_BOX_ROUNDS; i++) {
|
||||
out ^= key[i];
|
||||
out = sbox[out];
|
||||
out = rot8left(out, i%8);
|
||||
out ^= rot8right(key[i], 4);
|
||||
}
|
||||
rotatekey(key, out);
|
||||
if(len < 160/8) {
|
||||
fprintf(stderr, "key too small (got %ld, expected %d)\n", len, 160/8);
|
||||
return NULL;
|
||||
}
|
||||
else {
|
||||
for(i=S_BOX_ROUNDS-1; i>= 0; i--) {
|
||||
out ^= rot8left(key[i], 4);
|
||||
out = rot8right(out, i%8);
|
||||
out = revsbox[out];
|
||||
out ^= key[i];
|
||||
}
|
||||
rotatekey(key, in);
|
||||
}
|
||||
k = malloc(sizeof(ctx));
|
||||
memset(tmp, 0, 9);
|
||||
|
||||
memcpy(tmp, arg, 4);
|
||||
k->lcg = strtol(tmp, NULL, 16);
|
||||
|
||||
return out;
|
||||
memcpy(tmp, &arg[4], 4);
|
||||
k->d1u = strtol(tmp, NULL, 16);
|
||||
|
||||
memcpy(tmp, &arg[8], 4);
|
||||
k->decide = strtol(tmp, NULL, 16);
|
||||
|
||||
memcpy(tmp, &arg[12], 8);
|
||||
k->shift = strtoll(tmp, NULL, 16);
|
||||
|
||||
return k;
|
||||
}
|
||||
}
|
||||
|
||||
/* work on stdin and stdout */
|
||||
int handleio(byte *key, int encrypt) {
|
||||
byte in, out;
|
||||
/* diffuse context with prime numbers */
|
||||
void diffuse_context() {
|
||||
/* 32bits are random Sofie Germain primes,
|
||||
64bit is a Carmichael number(fermat pseudoprime), see
|
||||
https://oeis.org/A255578
|
||||
|
||||
while (fread(&in, 1, 1, stdin) == 1) {
|
||||
out = bytebox(in, key, encrypt);
|
||||
diffuse input key with those primes
|
||||
*/
|
||||
u32 tmplcg;
|
||||
int i, xRotBy = 29;
|
||||
|
||||
context->lcg ^= 0x85f62713;
|
||||
context->d1u ^= 0xc178f733;
|
||||
context->decide ^= 0x49a79a73;
|
||||
context->shift ^= 17905475062325518273U;
|
||||
|
||||
for(i=0; i<7; i++) {
|
||||
tmplcg = context->lcg;
|
||||
context->lcg ^= rot32left(context->d1u, (context->decide & 0xFF) % xRotBy);
|
||||
context->d1u ^= rot32left(context->decide, (context->d1u & 0xFF) % xRotBy);
|
||||
context->decide ^= rot32left(tmplcg, (context->lcg & 0xFF) % xRotBy);
|
||||
context->shift ^= (((u64)context->lcg << 32) + context->d1u);
|
||||
}
|
||||
}
|
||||
|
||||
/* actual stream (1byte) encrypt/decrypt */
|
||||
void io_loop() {
|
||||
byte out, K[8];
|
||||
int i;
|
||||
|
||||
w2a(combined64a(), K);
|
||||
|
||||
while(fread(&out, 1, 1, stdin) == 1) {
|
||||
for(i=0; i<8; i++) out ^= sbox[K[i]]; /* apply our sbox */
|
||||
fwrite(&out, 1, 1, stdout);
|
||||
w2a(combined64a(), K);
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/* work on stdin and stdout, in CBC 8bit mode */
|
||||
int cbc_handleio(byte *key, int encrypt) {
|
||||
byte in, out, iv;
|
||||
|
||||
if(encrypt) {
|
||||
iv = getiv();
|
||||
fwrite(&iv, 1, 1, stdout);
|
||||
}
|
||||
else {
|
||||
fread(&iv, 1, 1, stdin);
|
||||
}
|
||||
|
||||
while (fread(&in, 1, 1, stdin) == 1) {
|
||||
if(encrypt) {
|
||||
out = bytebox(iv ^ in, key, encrypt);
|
||||
iv = out;
|
||||
}
|
||||
else {
|
||||
out = iv ^ bytebox(in, key, encrypt);
|
||||
iv = in;
|
||||
}
|
||||
|
||||
fwrite(&out, 1, 1, stdout);
|
||||
}
|
||||
|
||||
return 0;
|
||||
fflush(stdout);
|
||||
}
|
||||
|
||||
|
||||
int main(int argc, char **argv) {
|
||||
byte key[K_HASH_ROUNDS];
|
||||
int encrypt;
|
||||
|
||||
if(argc != 3) {
|
||||
fprintf(stderr, "Usage: stream <passwd> <e|n>\ne=encrypt, n=decrypt\n");
|
||||
if(argc == 2) {
|
||||
context = parseargs(argv[1]);
|
||||
if(context == NULL) {
|
||||
return 1;
|
||||
}
|
||||
else {
|
||||
encrypt = 0;
|
||||
|
||||
if(strcmp(argv[2], "e") == 0)
|
||||
encrypt = 1;
|
||||
|
||||
reverse_sbox();
|
||||
|
||||
keyhash(argv[1], key);
|
||||
|
||||
return handleio(key, encrypt);
|
||||
diffuse_context();
|
||||
io_loop();
|
||||
return 0;
|
||||
}
|
||||
}
|
||||
else {
|
||||
fprintf(stderr, "usage: twenty4 <20 byte hex key>\n");
|
||||
return 1;
|
||||
}
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
Reference in New Issue
Block a user