- * number of Miller-Rabin iterations for an error rate of less than 2^-80 for
- * random 'b'-bit input, b >= 100 (taken from table 4.4 in the Handbook of
- * Applied Cryptography [Menezes, van Oorschot, Vanstone; CRC Press 1996];
- * original paper: Damgaard, Landrock, Pomerance: Average case error
- * estimates for the strong probable prime test. -- Math. Comp. 61 (1993)
- * 177-194)
+ * BN_prime_checks_for_size() returns the number of Miller-Rabin iterations
+ * that will be done for checking that a random number is probably prime. The
+ * error rate for accepting a composite number as prime depends on the size of
+ * the prime |b|. The error rates used are for calculating an RSA key with 2 primes,
+ * and so the level is what you would expect for a key of double the size of the
+ * prime.
+ *
+ * This table is generated using the algorithm of FIPS PUB 186-4
+ * Digital Signature Standard (DSS), section F.1, page 117.
+ * (https://dx.doi.org/10.6028/NIST.FIPS.186-4)
+ *
+ * The following magma script was used to generate the output:
+ * securitybits:=125;
+ * k:=1024;
+ * for t:=1 to 65 do
+ * for M:=3 to Floor(2*Sqrt(k-1)-1) do
+ * S:=0;
+ * // Sum over m
+ * for m:=3 to M do
+ * s:=0;
+ * // Sum over j
+ * for j:=2 to m do
+ * s+:=(RealField(32)!2)^-(j+(k-1)/j);
+ * end for;
+ * S+:=2^(m-(m-1)*t)*s;
+ * end for;
+ * A:=2^(k-2-M*t);
+ * B:=8*(Pi(RealField(32))^2-6)/3*2^(k-2)*S;
+ * pkt:=2.00743*Log(2)*k*2^-k*(A+B);
+ * seclevel:=Floor(-Log(2,pkt));
+ * if seclevel ge securitybits then
+ * printf "k: %5o, security: %o bits (t: %o, M: %o)\n",k,seclevel,t,M;
+ * break;
+ * end if;
+ * end for;
+ * if seclevel ge securitybits then break; end if;
+ * end for;
+ *
+ * It can be run online at:
+ * http://magma.maths.usyd.edu.au/calc
+ *
+ * And will output:
+ * k: 1024, security: 129 bits (t: 6, M: 23)
+ *
+ * k is the number of bits of the prime, securitybits is the level we want to
+ * reach.
+ *
+ * prime length | RSA key size | # MR tests | security level
+ * -------------+--------------|------------+---------------
+ * (b) >= 6394 | >= 12788 | 3 | 256 bit
+ * (b) >= 3747 | >= 7494 | 3 | 192 bit
+ * (b) >= 1345 | >= 2690 | 4 | 128 bit
+ * (b) >= 1080 | >= 2160 | 5 | 128 bit
+ * (b) >= 852 | >= 1704 | 5 | 112 bit
+ * (b) >= 476 | >= 952 | 5 | 80 bit
+ * (b) >= 400 | >= 800 | 6 | 80 bit
+ * (b) >= 347 | >= 694 | 7 | 80 bit
+ * (b) >= 308 | >= 616 | 8 | 80 bit
+ * (b) >= 55 | >= 110 | 27 | 64 bit
+ * (b) >= 6 | >= 12 | 34 | 64 bit