I wrote a brief J script to generate random RSA keys in various lengths. I put a copy in my Dropbox at the following URL…
https://www.dropbox.com/s/0y0tpgtjtv4vvd2/rsakeys.ijs In this script is a function called “genkey” which crashes J. genkey =: 3 : 0"0 q =. p =. randprime y while. q = p do. q =. randprime y end. if. p < q do. 'p q'=. q,p end. (p*q),p,q ) randprime y returns a random prime of length y bits with the upper two bits set as an extended precision integer. It seems rock solid and has been called millions of times without issue. genkey picks a prime, p, and another prime not equal to it, q, and swaps them if necessary so p is the larger one. It then returns a vector of length 3, consisting of p*q, p, and q. If you load this script, and type “genkey 32”, you get a “J has stopped working, reporting to Microsoft” dialogue box immediately. If I write another function, “keygen” which does the same thing as genkey, but phrased slightly differently, it works perfectly. keygen =: 3 : 0"0 z =. '' while. 2 > #z do. z =. ~. z , randprime y end. (*/z),\:~z ) keygen 5#32 13636890702424146503 3697445573 3688192411 14042631972443509627 3975272443 3532495489 15856784938324374101 4290006247 3696214883 12482175669738327193 3743048207 3334762199 14012721502477771067 4146478969 3379426643 I’m new to J programming, so I’m sure I’ve just done something dumb. Any insights would be appreciated. Thanks. ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
