diff --git a/README.md b/README.md
index 6b2b48c..d8d13ac 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,7 @@ Tool for generating Elliptic curve domain parameters.
  - `-s / --ansi[=SEED]`		Generate a curve from `SEED` (ANSI X9.62 verifiable procedure).
  - `-b / --brainpool[=SEED]`Generate a curve using the Brainpool verifiably pseudorandom algorithm from the original paper.
  - `--brainpool-rfc[=SEED]` Generate a curve using the Brainpool verifiably pseudorandom algorithm as per RFC 5639.
+ - `--nums`                 Generate a curve using the NUMS procedure (as per draft-black-numscurves-02).
  - `--twist`                Generate a twist of a given curve.
 
 #### Generation options
@@ -34,6 +35,7 @@ Tool for generating Elliptic curve domain parameters.
  - `--points=TYPE`			Generate points of given `TYPE` (random/prime/all/nonprime/none).
  - `-r / --random`			Generate a random curve (using Random approach).
  - `-u / --unique`			Generate a curve with only one generator.
+ - `--hex-check=HEX`        Generate a curve with `HEX` string in the hex expansion of its parameters.
  - `--metadata`				Compute the curve metadata (j-invariant, discriminant, trace of Frobenius, CM discriminant, embedding degree)
 
 #### IO options
diff --git a/src/exhaustive/exhaustive.c b/src/exhaustive/exhaustive.c
index a8d0f22..4eba6bd 100644
--- a/src/exhaustive/exhaustive.c
+++ b/src/exhaustive/exhaustive.c
@@ -7,6 +7,7 @@
 #include "arg.h"
 #include "brainpool.h"
 #include "brainpool_rfc.h"
+#include "nums.h"
 #include "check.h"
 #include "gen/curve.h"
 #include "gen/equation.h"
@@ -114,6 +115,14 @@ static void exhaustive_ginit(gen_f *generators) {
 				generators[OFFSET_ORDER] = &order_gen_prime;
 				generators[OFFSET_GENERATORS] = &brainpool_gen_gens;
 			} break;
+			case SEED_NUMS: {
+				generators[OFFSET_SEED] = &gen_skip;
+				generators[OFFSET_FIELD] = &nums_gen_field;
+				generators[OFFSET_A] = &nums_gen_a;
+				generators[OFFSET_B] = &nums_gen_b;  // TODO: Missing transformation from b -> -b.
+				generators[OFFSET_ORDER] = &nums_gen_order;
+				generators[OFFSET_GENERATORS] = &nums_gen_gens;
+			} break;
 			case SEED_FIPS:
 				break;
 			default:
@@ -227,12 +236,19 @@ static void exhaustive_cinit(check_t **validators) {
 				break;
 			case SEED_BRAINPOOL:
 			case SEED_BRAINPOOL_RFC: {
+				// TODO: Missing Brainpool CM disc check.
 				check_t *order_check = check_new(brainpool_check_order, NULL);
 				validators[OFFSET_ORDER] = order_check;
 				check_t *gens_check =
 				    check_new(gens_check_anomalous, brainpool_check_gens, NULL);
 				validators[OFFSET_GENERATORS] = gens_check;
 			} break;
+			case SEED_NUMS: {
+				// TODO: Missing CM disc check.
+				check_t *gens_check =
+				    check_new(gens_check_anomalous, brainpool_check_gens, NULL);
+				validators[OFFSET_GENERATORS] = gens_check;
+			} break;
 			case SEED_FIPS:
 				break;
 			default:
@@ -407,6 +423,7 @@ static void exhaustive_init(exhaustive_t *setup) {
 static void exhaustive_quit(exhaustive_t *setup) {
 	field_quit();
 	equation_quit();
+	nums_quit();
 	exhaustive_clear(setup);
 }
 
diff --git a/src/exhaustive/nums.c b/src/exhaustive/nums.c
new file mode 100644
index 0000000..7e41938
--- /dev/null
+++ b/src/exhaustive/nums.c
@@ -0,0 +1,111 @@
+/*
+ * ecgen, tool for generating Elliptic curve domain parameters
+ * Copyright (C) 2023 J08nY
+ */
+
+#include "nums.h"
+#include "math/subgroup.h"
+#include "obj/point.h"
+#include "obj/subgroup.h"
+
+GENERATOR(nums_gen_field) {
+	pari_sp ltop = avma;
+	GEN base = int2u(cfg->bits);
+	GEN c = stoi(1);
+	GEN p = subii(base, c);
+	while (!isprime(p)) {
+		c = addiu(c, 4);
+		p = subii(base, c);
+	}
+	curve->field = gerepilecopy(ltop, p);
+	return 1;
+}
+
+GENERATOR(nums_gen_a) {
+	curve-> a = gmodulo(stoi(-3), curve->field);
+	return 1;
+}
+
+static GEN b = NULL;
+static curve_t *curve_b = NULL;
+
+GENERATOR(nums_gen_b) {
+	pari_sp ltop = avma;
+	if (!b) {
+		b = gclone(gen_1);
+		curve->b = gmodulo(gen_1, curve->field);
+		curve_b = curve;
+		return 1;
+	} else {
+		if (curve_b == curve) {
+			// use b, add 1 to it, store it back modified,
+			GEN bn;
+			if (equaliu(b, 1)) {
+				bn = addiu(b, 2);
+			} else {
+				bn = addiu(b, 1);
+			}
+			gunclone(b);
+			b = gclone(bn);
+			curve->b = gerepilecopy(ltop, gmodulo(bn, curve->field));
+			return 1;
+		} else {
+			// dont use b, regenerate it,
+			gunclone(b);
+			b = gclone(gen_1);
+			curve->b = gerepilecopy(ltop, gmodulo(gen_1, curve->field));
+			curve_b = curve;
+			return 1;
+		}
+	}
+}
+
+GENERATOR(nums_gen_order) {
+	pari_sp ltop = avma;
+	GEN order = ellsea(curve->curve, 1);
+	GEN frobenius = subii(addis(curve->field, 1), order);
+	GEN twist_order = addii(order, muliu(frobenius, 2));
+	if (gequal0(order) || !(isprime(order)) || !(isprime(twist_order))) {
+		avma = ltop;
+		return -2;  // Just go one step back and regenerate the b.
+	} else {
+		curve->order = gerepilecopy(ltop, order);
+		obj_insert_shallow(curve->curve, 1, curve->order);
+		return 1;
+	}
+}
+
+GENERATOR(nums_gen_gens) {
+	pari_sp ltop = avma;
+	GEN x = stoi(1);
+	GEN Qy = ellordinate(curve->curve, x, 0);
+	while (glength(Qy) == 0) {
+		x = addiu(x, 1);
+		Qy = ellordinate(curve->curve, x, 0);
+	}
+	GEN P = NULL;
+	if (cmpii(lift(gel(Qy, 1)), lift(gel(Qy, 2))) < 0) {
+		P = mkvec2(gmodulo(x, curve->field), gel(Qy, 1));
+	} else {
+		P = mkvec2(gmodulo(x, curve->field), gel(Qy, 2));
+	}
+
+	curve->generators = subgroups_new(1);
+	curve->ngens = 1;
+	subgroup_t *sub = subgroup_new();
+	curve->generators[0] = sub;
+	point_t *G = point_new();
+	sub->generator = G;
+	G->point = P;
+	G->order = ellorder(curve->curve, G->point, NULL);
+	G->cofactor = divii(curve->order, G->order);
+	gerepileall(ltop, 3, &G->point, &G->order, &G->cofactor);
+	return 1;
+}
+
+
+void nums_quit(void) {
+	if (b && isclone(b)) {
+		gunclone(b);
+	}
+}
\ No newline at end of file
diff --git a/src/exhaustive/nums.h b/src/exhaustive/nums.h
new file mode 100644
index 0000000..40cb1b4
--- /dev/null
+++ b/src/exhaustive/nums.h
@@ -0,0 +1,60 @@
+/*
+ * ecgen, tool for generating Elliptic curve domain parameters
+ * Copyright (C) 2023 J08nY
+ */
+/*
+ * @file nums.h
+ */
+#ifndef ECGEN_EXHAUSTIVE_NUMS_H
+#define ECGEN_EXHAUSTIVE_NUMS_H
+
+#include "misc/types.h"
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(nums_gen_field);
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(nums_gen_a);
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(nums_gen_b);
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(nums_gen_order);
+
+/**
+ * @brief
+ * @param curve
+ * @param args
+ * @param state
+ * @return
+ */
+GENERATOR(nums_gen_gens);
+
+void nums_quit();
+
+#endif  // ECGEN_EXHAUSTIVE_NUMS_H
diff --git a/src/gen/seed.c b/src/gen/seed.c
index 3b10d26..5dca17a 100644
--- a/src/gen/seed.c
+++ b/src/gen/seed.c
@@ -49,6 +49,8 @@ void seed_free(seed_t **seed) {
 				break;
 			case SEED_FIPS:
 				break;
+			case SEED_NUMS:
+				break;
 			case SEED_NONE:
 				break;
 		}
diff --git a/src/io/cli.c b/src/io/cli.c
index ad3df9b..fec3283 100644
--- a/src/io/cli.c
+++ b/src/io/cli.c
@@ -41,6 +41,7 @@ enum opt_keys {
 	OPT_HEXCHECK,
 	OPT_METADATA,
 	OPT_SUPERSINGULAR,
+	OPT_NUMS,
 	OPT_BRAINPOOL_RFC,
 	OPT_TWIST,
 };
@@ -58,6 +59,7 @@ struct argp_option cli_options[] = {
 		{"ansi",          OPT_ANSI,          "SEED",  OPTION_ARG_OPTIONAL, "Generate a curve from SEED (ANSI X9.62 verifiable procedure).",                        2},
 		{"brainpool",     OPT_BRAINPOOL,     "SEED",  OPTION_ARG_OPTIONAL, "Generate a curve from SEED (Brainpool procedure).",                                    2},
 		{"brainpool-rfc", OPT_BRAINPOOL_RFC, "SEED",  OPTION_ARG_OPTIONAL, "Generate a curve from SEED (Brainpool procedure, as per RFC 5639).",                   2},
+		{"nums",		  OPT_NUMS, 		 0,		  0,				   "Generate a curve using the NUMS procedure.", 										   2},
 		{"invalid",       OPT_INVALID,       "RANGE", OPTION_ARG_OPTIONAL, "Generate a set of invalid curves, for a given curve (using Invalid curve algorithm).", 2},
 		{"twist",         OPT_TWIST,         0,       0,                   "Generate a twist of a given curve.",                                                   2},
 
@@ -175,11 +177,16 @@ static void cli_end(struct argp_state *state) {
 			break;
 	}
 
-	if (cfg->method == METHOD_SEED && cfg->seed_algo == SEED_BRAINPOOL &&
+	if (cfg->method == METHOD_SEED && (cfg->seed_algo == SEED_BRAINPOOL || cfg->seed_algo == SEED_BRAINPOOL_RFC) &&
 	    cfg->field == FIELD_BINARY) {
 		argp_failure(state, 1, 0,
 		             "Brainpool algorithm only creates prime field curves.");
 	}
+	if (cfg->method == METHOD_SEED && cfg->seed_algo == SEED_NUMS &&
+	    cfg->field == FIELD_BINARY) {
+		argp_failure(state, 1, 0,
+		             "NUMS algorithm only creates prime field curves.");
+	}
 	if (cfg->method == METHOD_CM && cfg->field == FIELD_BINARY) {
 		argp_failure(state, 1, 0,
 		             "Complex multiplication only creates prime field curves.");
@@ -266,6 +273,10 @@ error_t cli_parse(int key, char *arg, struct argp_state *state) {
 				cfg->seed = arg;
 			}
 			break;
+		case OPT_NUMS:
+			cfg->method |= METHOD_SEED;
+			cfg->seed_algo = SEED_NUMS;
+			break;
 		case OPT_BRAINPOOL_RFC:
 			cfg->method |= METHOD_SEED;
 			cfg->seed_algo = SEED_BRAINPOOL_RFC;
diff --git a/src/io/output.c b/src/io/output.c
index 12b412d..a69b905 100644
--- a/src/io/output.c
+++ b/src/io/output.c
@@ -181,40 +181,40 @@ char *output_sjson_begin() { return output_malloc("[\n"); }
 
 char *output_sjson_end() { return output_malloc("]\n"); }
 
-void output_f(FILE *out, curve_t *curve) {
+void output_f(FILE *output, curve_t *curve) {
 	char *s = output_s(curve);
 	if (s) {
-		fprintf(out, "%s", s);
+		fprintf(output, "%s", s);
 		try_free(s);
 	}
 }
 
 void output_o(curve_t *curve) { output_f(out, curve); }
 
-void output_f_separator(FILE *out) {
+void output_f_separator(FILE *output) {
 	char *s = output_s_separator();
 	if (s) {
-		fprintf(out, "%s", s);
+		fprintf(output, "%s", s);
 		try_free(s);
 	}
 }
 
 void output_o_separator() { output_f_separator(out); }
 
-void output_f_begin(FILE *out) {
+void output_f_begin(FILE *output) {
 	char *s = output_s_begin();
 	if (s) {
-		fprintf(out, "%s", s);
+		fprintf(output, "%s", s);
 		try_free(s);
 	}
 }
 
 void output_o_begin() { output_f_begin(out); }
 
-void output_f_end(FILE *out) {
+void output_f_end(FILE *output) {
 	char *s = output_s_end();
 	if (s) {
-		fprintf(out, "%s", s);
+		fprintf(output, "%s", s);
 		try_free(s);
 	}
 }
diff --git a/src/misc/config.h b/src/misc/config.h
index d73d26f..dcdca58 100644
--- a/src/misc/config.h
+++ b/src/misc/config.h
@@ -59,7 +59,8 @@ typedef enum {
 	SEED_ANSI,
 	SEED_BRAINPOOL,
 	SEED_BRAINPOOL_RFC,
-	SEED_FIPS
+	SEED_FIPS,
+	SEED_NUMS
 } seed_e;
 
 /**