diff --git a/include/Makefile.am b/include/Makefile.am
index 42a2dc2..b035906 100644
--- a/include/Makefile.am
+++ b/include/Makefile.am
@@ -43,6 +43,7 @@
                        osmocom/gsm/a5.h \
                        osmocom/gsm/abis_nm.h \
                        osmocom/gsm/comp128.h \
+                       osmocom/gsm/comp128v23.h \
                        osmocom/gsm/gan.h \
                        osmocom/gsm/gsm0411_smc.h \
                        osmocom/gsm/gsm0411_smr.h \
diff --git a/include/osmocom/gsm/comp128v23.h b/include/osmocom/gsm/comp128v23.h
new file mode 100644
index 0000000..aa26e56
--- /dev/null
+++ b/include/osmocom/gsm/comp128v23.h
@@ -0,0 +1,23 @@
+/*
+ * COMP128v23 header
+ *
+ * See comp128v23.c for details
+ */
+
+#ifndef __COMP128V23_H__
+#define __COMP128V23_H__
+
+#include <stdint.h>
+
+/*
+ * Performs the COMP128 version 2 and 3 algorithm (used as A3/A8)
+ * ki    : uint8_t [16]
+ * srand : uint8_t [16]
+ * version : uint8_t (2 or 3)
+ * sres  : uint8_t [4]
+ * kc    : uint8_t [8]
+ * returns 1 if not version 2 or 3 specified
+ */
+int comp128v23(const uint8_t *ki, const uint8_t *rand, uint8_t version, uint8_t *sres, uint8_t *kc);
+
+#endif /* __COMP128V23_H__ */
diff --git a/src/gsm/Makefile.am b/src/gsm/Makefile.am
index fa2265a..3162a7f 100644
--- a/src/gsm/Makefile.am
+++ b/src/gsm/Makefile.am
@@ -11,14 +11,15 @@
 
 lib_LTLIBRARIES = libosmogsm.la
 
-libosmogsm_la_SOURCES = a5.c rxlev_stat.c tlv_parser.c comp128.c gsm_utils.c \
-                        rsl.c gsm48.c gsm48_ie.c gsm0808.c sysinfo.c \
+libosmogsm_la_SOURCES = a5.c rxlev_stat.c tlv_parser.c comp128.c comp128v23.c \
+			gsm_utils.c rsl.c gsm48.c gsm48_ie.c gsm0808.c sysinfo.c \
 			gprs_cipher_core.c gsm0480.c abis_nm.c gsm0502.c \
 			gsm0411_utils.c gsm0411_smc.c gsm0411_smr.c \
 			lapd_core.c lapdm.c \
-			auth_core.c auth_comp128v1.c auth_milenage.c \
-			milenage/aes-encblock.c milenage/aes-internal.c \
-			milenage/aes-internal-enc.c milenage/milenage.c gan.c
+			auth_core.c auth_comp128v1.c auth_comp128v23.c \
+			auth_milenage.c milenage/aes-encblock.c \
+			milenage/aes-internal.c milenage/aes-internal-enc.c \
+			milenage/milenage.c gan.c
 
 libosmogsm_la_LDFLAGS = $(LTLDFLAGS_OSMOGSM) -version-info $(LIBVERSION) -no-undefined
 libosmogsm_la_LIBADD = $(top_builddir)/src/libosmocore.la
diff --git a/src/gsm/auth_comp128v23.c b/src/gsm/auth_comp128v23.c
new file mode 100644
index 0000000..36383d9
--- /dev/null
+++ b/src/gsm/auth_comp128v23.c
@@ -0,0 +1,68 @@
+/* registers COMP128 version 2 and 3 A3/A8 algorithms for the
+ * GSM/GPRS/3G authentication core infrastructure
+ *
+ */
+
+/* (C) 2010-2011 by Harald Welte <laforge@gnumonks.org>
+ * (C) 2013 by Kévin Redon <kevredon@mail.tsaitgaist.info>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <osmocom/crypt/auth.h>
+#include <osmocom/gsm/comp128v23.h>
+
+static int c128v2_gen_vec(struct osmo_auth_vector *vec,
+			  struct osmo_sub_auth_data *aud,
+			  const uint8_t *_rand)
+{
+	comp128v23(aud->u.gsm.ki, _rand, 2, vec->sres, vec->kc);
+	vec->auth_types = OSMO_AUTH_TYPE_GSM;
+
+	return 0;
+}
+
+static struct osmo_auth_impl c128v2_alg = {
+	.algo = OSMO_AUTH_ALG_COMP128v2,
+	.name = "COMP128v2 (libosmogsm built-in)",
+	.priority = 1000,
+	.gen_vec = &c128v2_gen_vec,
+};
+
+static int c128v3_gen_vec(struct osmo_auth_vector *vec,
+			  struct osmo_sub_auth_data *aud,
+			  const uint8_t *_rand)
+{
+	comp128v23(aud->u.gsm.ki, _rand, 3, vec->sres, vec->kc);
+	vec->auth_types = OSMO_AUTH_TYPE_GSM;
+
+	return 0;
+}
+
+static struct osmo_auth_impl c128v3_alg = {
+	.algo = OSMO_AUTH_ALG_COMP128v3,
+	.name = "COMP128v3 (libosmogsm built-in)",
+	.priority = 1000,
+	.gen_vec = &c128v3_gen_vec,
+};
+
+static __attribute__((constructor)) void on_dso_load_c128(void)
+{
+	osmo_auth_register(&c128v2_alg);
+	osmo_auth_register(&c128v3_alg);
+}
diff --git a/src/gsm/comp128v23.c b/src/gsm/comp128v23.c
new file mode 100644
index 0000000..9004208
--- /dev/null
+++ b/src/gsm/comp128v23.c
@@ -0,0 +1,166 @@
+/* COMP128 version 2 and 3 implementation
+ *
+ * This code is a C conversion of the original code from
+ * http://www.hackingprojects.net/
+ *
+ */
+
+/* (C) 2013 by Kévin Redon <kevredon@mail.tsaitgaist.info>
+ *
+ * All Rights Reserved
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ *
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+static const uint8_t table0[256] = {
+	197, 235, 60, 151, 98, 96, 3, 100, 248, 118, 42, 117, 172, 211, 181, 203, 61,
+	126, 156, 87, 149, 224, 55, 132, 186, 63, 238, 255, 85, 83, 152, 33, 160,
+	184, 210, 219, 159, 11, 180, 194, 130, 212, 147, 5, 215, 92, 27, 46, 113,
+	187, 52, 25, 185, 79, 221, 48, 70, 31, 101, 15, 195, 201, 50, 222, 137,
+	233, 229, 106, 122, 183, 178, 177, 144, 207, 234, 182, 37, 254, 227, 231, 54,
+	209, 133, 65, 202, 69, 237, 220, 189, 146, 120, 68, 21, 125, 38, 30, 2,
+	155, 53, 196, 174, 176, 51, 246, 167, 76, 110, 20, 82, 121, 103, 112, 56,
+	173, 49, 217, 252, 0, 114, 228, 123, 12, 93, 161, 253, 232, 240, 175, 67,
+	128, 22, 158, 89, 18, 77, 109, 190, 17, 62, 4, 153, 163, 59, 145, 138,
+	7, 74, 205, 10, 162, 80, 45, 104, 111, 150, 214, 154, 28, 191, 169, 213,
+	88, 193, 198, 200, 245, 39, 164, 124, 84, 78, 1, 188, 170, 23, 86, 226,
+	141, 32, 6, 131, 127, 199, 40, 135, 16, 57, 71, 91, 225, 168, 242, 206,
+	97, 166, 44, 14, 90, 236, 239, 230, 244, 223, 108, 102, 119, 148, 251, 29,
+	216, 8, 9, 249, 208, 24, 105, 94, 34, 64, 95, 115, 72, 134, 204, 43,
+	247, 243, 218, 47, 58, 73, 107, 241, 179, 116, 66, 36, 143, 81, 250, 139,
+	19, 13, 142, 140, 129, 192, 99, 171, 157, 136, 41, 75, 35, 165, 26
+}, table1[256] = {
+	170, 42, 95, 141, 109, 30, 71, 89, 26, 147, 231, 205, 239, 212, 124, 129, 216,
+	79, 15, 185, 153, 14, 251, 162, 0, 241, 172, 197, 43, 10, 194, 235, 6,
+	20, 72, 45, 143, 104, 161, 119, 41, 136, 38, 189, 135, 25, 93, 18, 224,
+	171, 252, 195, 63, 19, 58, 165, 23, 55, 133, 254, 214, 144, 220, 178, 156,
+	52, 110, 225, 97, 183, 140, 39, 53, 88, 219, 167, 16, 198, 62, 222, 76,
+	139, 175, 94, 51, 134, 115, 22, 67, 1, 249, 217, 3, 5, 232, 138, 31,
+	56, 116, 163, 70, 128, 234, 132, 229, 184, 244, 13, 34, 73, 233, 154, 179,
+	131, 215, 236, 142, 223, 27, 57, 246, 108, 211, 8, 253, 85, 66, 245, 193,
+	78, 190, 4, 17, 7, 150, 127, 152, 213, 37, 186, 2, 243, 46, 169, 68,
+	101, 60, 174, 208, 158, 176, 69, 238, 191, 90, 83, 166, 125, 77, 59, 21,
+	92, 49, 151, 168, 99, 9, 50, 146, 113, 117, 228, 65, 230, 40, 82, 54,
+	237, 227, 102, 28, 36, 107, 24, 44, 126, 206, 201, 61, 114, 164, 207, 181,
+	29, 91, 64, 221, 255, 48, 155, 192, 111, 180, 210, 182, 247, 203, 148, 209,
+	98, 173, 11, 75, 123, 250, 118, 32, 47, 240, 202, 74, 177, 100, 80, 196,
+	33, 248, 86, 157, 137, 120, 130, 84, 204, 122, 81, 242, 188, 200, 149, 226,
+	218, 160, 187, 106, 35, 87, 105, 96, 145, 199, 159, 12, 121, 103, 112
+};
+
+#define RAND_SIZE 16
+#define KI_SIZE 16
+#define SRES_SIZE 4
+#define KC_SIZE 8
+
+static void
+_comp128v23_internal(uint8_t *output, const uint8_t *kxor, const uint8_t *rand)
+{
+	uint8_t temp[RAND_SIZE];
+	uint8_t km_rm[RAND_SIZE+KI_SIZE];
+	uint8_t i,j,k,z;
+
+	memset(temp,0,sizeof(temp)/sizeof(uint8_t));
+	memcpy(km_rm,rand,RAND_SIZE);
+	memcpy(km_rm+RAND_SIZE,kxor,KI_SIZE);
+
+	for (i=0; i<5; i++) {
+		for (z=0; z<16; z++) {
+			temp[z] = table0[table1[km_rm[16+z]]^km_rm[z]];
+		}
+		j=0;
+		while ((1<<i)>j) {
+			k = 0;
+			while ((1<<(4-i))>k) {
+				km_rm[((2*k+1)<<i)+j] = table0[table1[temp[(k<<i)+j]]^(km_rm[(k<<i)+16+j])];
+				km_rm[(k<<(i+1))+j] = temp[(k<<i)+j];
+				k++;
+			}
+			j++;
+		}
+	}
+
+	memset(output,0,16);
+
+	for (i=0; i<16; i++) {
+		for (j=0; j<8; j++) {
+			output[i] ^= (((km_rm[(19*(j+8*i)+19)%256/8]>>(3*j+3)%8)&1)<< j);
+		}
+	}
+}
+
+int
+comp128v23(const uint8_t *ki, const uint8_t *rand, uint8_t version, uint8_t *sres, uint8_t *kc)
+{
+	uint8_t k_mix[KI_SIZE];
+	uint8_t rand_mix[RAND_SIZE];
+	uint8_t katyvasz[KI_SIZE];
+	uint8_t output[KI_SIZE];
+	uint8_t i,s;
+
+	if (!(version==2 || version==3))
+		return 1;
+
+	memset(k_mix,0,sizeof(k_mix)/sizeof(uint8_t));
+	memset(rand_mix,0,sizeof(rand_mix)/sizeof(uint8_t));
+	memset(katyvasz,0,sizeof(katyvasz)/sizeof(uint8_t));
+	memset(output,0,sizeof(output)/sizeof(uint8_t));
+
+	for (i=0; i<8; i++) {
+		k_mix[i] = ki[15 - i];
+		k_mix[15 - i] = ki[i];
+	}
+
+	for (i=0; i<8; i++) {
+		rand_mix[i] = rand[15 - i];
+		rand_mix[15 - i] = rand[i];
+	}
+
+	for (i=0; i<16; i++) {
+		katyvasz[i] = k_mix[i]^rand_mix[i];
+	}
+
+	for (i=0; i<8; i++) {
+		_comp128v23_internal(rand_mix,katyvasz,rand_mix);
+	}
+
+	for (i=0; i<16; i++) {
+		output[i] = rand_mix[15-i];
+	}
+
+	if (version==2) {
+		output[15] = 0;
+		output[14] = 4*(output[14]>>2);
+	}
+
+	s = 8;
+	i = 0;
+	while (i<4) {
+		output[s+i-4] = output[s+i];
+		output[s+i] = output[s+i+4];
+		i++;
+	}
+
+	/* the algorithm uses 16 bytes until this point, but only 12 bytes are effective
+	 * also 12 bytes coming out from the SIM card */
+	memcpy(sres,output,SRES_SIZE*sizeof(uint8_t));
+	memcpy(kc,&output[SRES_SIZE],KC_SIZE*sizeof(uint8_t));
+
+	return 0;
+}