diff options
Diffstat (limited to 'usr.bin/ssh/key.c')
| -rw-r--r-- | usr.bin/ssh/key.c | 105 |
1 files changed, 104 insertions, 1 deletions
diff --git a/usr.bin/ssh/key.c b/usr.bin/ssh/key.c index e55955671ef..40fe5b3108b 100644 --- a/usr.bin/ssh/key.c +++ b/usr.bin/ssh/key.c @@ -1,4 +1,4 @@ -/* $OpenBSD: key.c,v 1.69 2007/07/12 05:48:05 ray Exp $ */ +/* $OpenBSD: key.c,v 1.70 2008/06/11 21:01:35 grunk Exp $ */ /* * read_bignum(): * Copyright (c) 1995 Tatu Ylonen <ylo@cs.hut.fi>, Espoo, Finland @@ -33,6 +33,7 @@ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. */ +#include <sys/param.h> #include <sys/types.h> #include <openssl/evp.h> @@ -291,6 +292,105 @@ key_fingerprint_bubblebabble(u_char *dgst_raw, u_int dgst_raw_len) return retval; } +/* + * Draw an ASCII-Art representing the fingerprint so human brain can + * profit from its built-in pattern recognition ability. + * This technique is called "random art" and can be found in some + * scientific publications like this original paper: + * + * "Hash Visualization: a New Technique to improve Real-World Security", + * Perrig A. and Song D., 1999, International Workshop on Cryptographic + * Techniques and E-Commerce (CrypTEC '99) + * sparrow.ece.cmu.edu/~adrian/projects/validation/validation.pdf + * + * The subject came up in a talk by Dan Kaminsky, too. + * + * If you see the picture is different, the key is different. + * If the picture looks the same, you still know nothing. + * + * The algorithm used here is a worm crawling over a discrete plane, + * leaving a trace (augmenting the field) everywhere it goes. + * Movement is taken from dgst_raw 2bit-wise. Bumping into walls + * makes the respective movement vector be ignored for this turn. + * Graphs are not unambiguous, because circles in graphs can be + * walked in either direction. + */ +#define FLDSIZE_Y 8 +#define FLDSIZE_X FLDSIZE_Y * 2 +static char * +key_fingerprint_randomart(u_char *dgst_raw, u_int dgst_raw_len) +{ + /* + * Chars to be used after each other every time the worm + * intersects with itself. Matter of taste. + */ + char *augmentation_string = " .o+=*BOX@%&#/^"; + char *retval, *p; + char field[FLDSIZE_X][FLDSIZE_Y]; + u_int i, b; + int x, y; + + retval = xcalloc(1, (FLDSIZE_X + 3) * (FLDSIZE_Y + 2)); + + /* initialize field */ + memset(field, ' ', FLDSIZE_X * FLDSIZE_Y * sizeof(char)); + x = FLDSIZE_X / 2; + y = FLDSIZE_Y / 2; + field[x][y] = '.'; + + /* process raw key */ + for (i = 0; i < dgst_raw_len; i++) { + int input; + /* each byte conveys four 2-bit move commands */ + input = dgst_raw[i]; + for (b = 0; b < 4; b++) { + /* evaluate 2 bit, rest is shifted later */ + x += (input & 0x1) ? 1 : -1; + y += (input & 0x2) ? 1 : -1; + + /* assure we are still in bounds */ + x = MAX(x, 0); + y = MAX(y, 0); + x = MIN(x, FLDSIZE_X - 1); + y = MIN(y, FLDSIZE_Y - 1); + + /* augment the field */ + p = strchr(augmentation_string, field[x][y]); + if (*++p != '\0') + field[x][y] = *p; + + input = input >> 2; + } + } + + /* fill in retval */ + p = retval; + + /* output upper border */ + *p++ = '+'; + for (i = 0; i < FLDSIZE_X; i++) + *p++ = '-'; + *p++ = '+'; + *p++ = '\n'; + + /* output content */ + for (y = 0; y < FLDSIZE_Y; y++) { + *p++ = '|'; + for (x = 0; x < FLDSIZE_X; x++) + *p++ = field[x][y]; + *p++ = '|'; + *p++ = '\n'; + } + + /* output lower border */ + *p++ = '+'; + for (i = 0; i < FLDSIZE_X; i++) + *p++ = '-'; + *p++ = '+'; + + return retval; +} + char * key_fingerprint(const Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep) { @@ -308,6 +408,9 @@ key_fingerprint(const Key *k, enum fp_type dgst_type, enum fp_rep dgst_rep) case SSH_FP_BUBBLEBABBLE: retval = key_fingerprint_bubblebabble(dgst_raw, dgst_raw_len); break; + case SSH_FP_RANDOMART: + retval = key_fingerprint_randomart(dgst_raw, dgst_raw_len); + break; default: fatal("key_fingerprint_ex: bad digest representation %d", dgst_rep); |