diff --git a/openbsc/src/a3a8.c b/openbsc/src/a3a8.c
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+/* An implementation of the GSM A3A8 algorithm.  (Specifically, COMP128.) 
+ */
+
+/* Copyright 1998, Marc Briceno, Ian Goldberg, and David Wagner.
+ * All rights reserved.
+ * 
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ *  * Redistributions of source code must retain the above copyright notice,
+ *    this list of conditions and the following disclaimer.
+ *
+ *  * Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ *  * Neither the name of the authors nor the names of the contributors
+ *    may be used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+ * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+ * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+ * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
+ * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
+ * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
+ * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ */
+
+/*
+ * Coded in C merely because C is a much more precise, concise form of
+ * expression for these purposes.  See Judge Patel if you have any problems
+ * with this...
+ * Of course, it's only authentication, so it should be exportable for the
+ * usual boring reasons.
+ */
+
+typedef unsigned char Byte;
+
+#include <stdio.h>
+/* #define TEST */
+ 
+/*
+ * rand[0..15]: the challenge from the base station
+ * key[0..15]: the SIM's A3/A8 long-term key Ki
+ * simoutput[0..11]: what you'd get back if you fed rand and key to a real
+ * SIM.
+ *
+ *   The GSM spec states that simoutput[0..3] is SRES,
+ *   and simoutput[4..11] is Kc (the A5 session key).
+ *   (See GSM 11.11, Section 8.16.  See also the leaked document
+ *   referenced below.)
+ *   Note that Kc is bits 74..127 of the COMP128 output, followed by 10
+ *   zeros.
+ *   In other words, A5 is keyed with only 54 bits of entropy. This
+ *   represents a deliberate weakening of the key used for voice privacy
+ *   by a factor of over 1000.
+ * 
+ * Verified with a Pacific Bell Schlumberger SIM.  Your mileage may vary.
+ *
+ * Marc Briceno <marc@scard.org>, Ian Goldberg <iang@cs.berkeley.edu>,
+ * and David Wagner <daw@cs.berkeley.edu>
+ */
+
+void A3A8(/* in */ Byte rand[16], /* in */ Byte key[16],
+	/* out */ Byte simoutput[12]);
+
+/* The compression tables. */
+static const Byte table_0[512] = {
+        102,177,186,162,  2,156,112, 75, 55, 25,  8, 12,251,193,246,188,
+        109,213,151, 53, 42, 79,191,115,233,242,164,223,209,148,108,161,
+        252, 37,244, 47, 64,211,  6,237,185,160,139,113, 76,138, 59, 70,
+         67, 26, 13,157, 63,179,221, 30,214, 36,166, 69,152,124,207,116,
+        247,194, 41, 84, 71,  1, 49, 14, 95, 35,169, 21, 96, 78,215,225,
+        182,243, 28, 92,201,118,  4, 74,248,128, 17, 11,146,132,245, 48,
+        149, 90,120, 39, 87,230,106,232,175, 19,126,190,202,141,137,176,
+        250, 27,101, 40,219,227, 58, 20, 51,178, 98,216,140, 22, 32,121,
+         61,103,203, 72, 29,110, 85,212,180,204,150,183, 15, 66,172,196,
+         56,197,158,  0,100, 45,153,  7,144,222,163,167, 60,135,210,231,
+        174,165, 38,249,224, 34,220,229,217,208,241, 68,206,189,125,255,
+        239, 54,168, 89,123,122, 73,145,117,234,143, 99,129,200,192, 82,
+        104,170,136,235, 93, 81,205,173,236, 94,105, 52, 46,228,198,  5,
+         57,254, 97,155,142,133,199,171,187, 50, 65,181,127,107,147,226,
+        184,218,131, 33, 77, 86, 31, 44, 88, 62,238, 18, 24, 43,154, 23,
+         80,159,134,111,  9,114,  3, 91, 16,130, 83, 10,195,240,253,119,
+        177,102,162,186,156,  2, 75,112, 25, 55, 12,  8,193,251,188,246,
+        213,109, 53,151, 79, 42,115,191,242,233,223,164,148,209,161,108,
+         37,252, 47,244,211, 64,237,  6,160,185,113,139,138, 76, 70, 59,
+         26, 67,157, 13,179, 63, 30,221, 36,214, 69,166,124,152,116,207,
+        194,247, 84, 41,  1, 71, 14, 49, 35, 95, 21,169, 78, 96,225,215,
+        243,182, 92, 28,118,201, 74,  4,128,248, 11, 17,132,146, 48,245,
+         90,149, 39,120,230, 87,232,106, 19,175,190,126,141,202,176,137,
+         27,250, 40,101,227,219, 20, 58,178, 51,216, 98, 22,140,121, 32,
+        103, 61, 72,203,110, 29,212, 85,204,180,183,150, 66, 15,196,172,
+        197, 56,  0,158, 45,100,  7,153,222,144,167,163,135, 60,231,210,
+        165,174,249, 38, 34,224,229,220,208,217, 68,241,189,206,255,125,
+         54,239, 89,168,122,123,145, 73,234,117, 99,143,200,129, 82,192,
+        170,104,235,136, 81, 93,173,205, 94,236, 52,105,228, 46,  5,198,
+        254, 57,155, 97,133,142,171,199, 50,187,181, 65,107,127,226,147,
+        218,184, 33,131, 86, 77, 44, 31, 62, 88, 18,238, 43, 24, 23,154,
+        159, 80,111,134,114,  9, 91,  3,130, 16, 10, 83,240,195,119,253
+    }, table_1[256] = {
+         19, 11, 80,114, 43,  1, 69, 94, 39, 18,127,117, 97,  3, 85, 43,
+         27,124, 70, 83, 47, 71, 63, 10, 47, 89, 79,  4, 14, 59, 11,  5,
+         35,107,103, 68, 21, 86, 36, 91, 85,126, 32, 50,109, 94,120,  6,
+         53, 79, 28, 45, 99, 95, 41, 34, 88, 68, 93, 55,110,125,105, 20,
+         90, 80, 76, 96, 23, 60, 89, 64,121, 56, 14, 74,101,  8, 19, 78,
+         76, 66,104, 46,111, 50, 32,  3, 39,  0, 58, 25, 92, 22, 18, 51,
+         57, 65,119,116, 22,109,  7, 86, 59, 93, 62,110, 78, 99, 77, 67,
+         12,113, 87, 98,102,  5, 88, 33, 38, 56, 23,  8, 75, 45, 13, 75,
+         95, 63, 28, 49,123,120, 20,112, 44, 30, 15, 98,106,  2,103, 29,
+         82,107, 42,124, 24, 30, 41, 16,108,100,117, 40, 73, 40,  7,114,
+         82,115, 36,112, 12,102,100, 84, 92, 48, 72, 97,  9, 54, 55, 74,
+        113,123, 17, 26, 53, 58,  4,  9, 69,122, 21,118, 42, 60, 27, 73,
+        118,125, 34, 15, 65,115, 84, 64, 62, 81, 70,  1, 24,111,121, 83,
+        104, 81, 49,127, 48,105, 31, 10,  6, 91, 87, 37, 16, 54,116,126,
+         31, 38, 13,  0, 72,106, 77, 61, 26, 67, 46, 29, 96, 37, 61, 52,
+        101, 17, 44,108, 71, 52, 66, 57, 33, 51, 25, 90,  2,119,122, 35
+    }, table_2[128] = {
+         52, 50, 44,  6, 21, 49, 41, 59, 39, 51, 25, 32, 51, 47, 52, 43,
+         37,  4, 40, 34, 61, 12, 28,  4, 58, 23,  8, 15, 12, 22,  9, 18,
+         55, 10, 33, 35, 50,  1, 43,  3, 57, 13, 62, 14,  7, 42, 44, 59,
+         62, 57, 27,  6,  8, 31, 26, 54, 41, 22, 45, 20, 39,  3, 16, 56,
+         48,  2, 21, 28, 36, 42, 60, 33, 34, 18,  0, 11, 24, 10, 17, 61,
+         29, 14, 45, 26, 55, 46, 11, 17, 54, 46,  9, 24, 30, 60, 32,  0,
+         20, 38,  2, 30, 58, 35,  1, 16, 56, 40, 23, 48, 13, 19, 19, 27,
+         31, 53, 47, 38, 63, 15, 49,  5, 37, 53, 25, 36, 63, 29,  5,  7
+    }, table_3[64] = {
+          1,  5, 29,  6, 25,  1, 18, 23, 17, 19,  0,  9, 24, 25,  6, 31,
+         28, 20, 24, 30,  4, 27,  3, 13, 15, 16, 14, 18,  4,  3,  8,  9,
+         20,  0, 12, 26, 21,  8, 28,  2, 29,  2, 15,  7, 11, 22, 14, 10,
+         17, 21, 12, 30, 26, 27, 16, 31, 11,  7, 13, 23, 10,  5, 22, 19
+    }, table_4[32] = {
+         15, 12, 10,  4,  1, 14, 11,  7,  5,  0, 14,  7,  1,  2, 13,  8,
+         10,  3,  4,  9,  6,  0,  3,  2,  5,  6,  8,  9, 11, 13, 15, 12
+    }, *table[5] = { table_0, table_1, table_2, table_3, table_4 };
+
+/*
+ * This code derived from a leaked document from the GSM standards.
+ * Some missing pieces were filled in by reverse-engineering a working SIM.
+ * We have verified that this is the correct COMP128 algorithm.
+ * 
+ * The first page of the document identifies it as
+ * 	_Technical Information: GSM System Security Study_.
+ * 	10-1617-01, 10th June 1988.
+ * The bottom of the title page is marked
+ * 	Racal Research Ltd.
+ * 	Worton Drive, Worton Grange Industrial Estate,
+ * 	Reading, Berks. RG2 0SB, England.
+ * 	Telephone: Reading (0734) 868601   Telex: 847152
+ * The relevant bits are in Part I, Section 20 (pages 66--67).  Enjoy!
+ * 
+ * Note: There are three typos in the spec (discovered by
+ * reverse-engineering).
+ * First, "z = (2 * x[n] + x[n]) mod 2^(9-j)" should clearly read
+ * "z = (2 * x[m] + x[n]) mod 2^(9-j)".
+ * Second, the "k" loop in the "Form bits from bytes" section is severely
+ * botched: the k index should run only from 0 to 3, and clearly the range
+ * on "the (8-k)th bit of byte j" is also off (should be 0..7, not 1..8,
+ * to be consistent with the subsequent section).
+ * Third, SRES is taken from the first 8 nibbles of x[], not the last 8 as
+ * claimed in the document.  (And the document doesn't specify how Kc is
+ * derived, but that was also easily discovered with reverse engineering.)
+ * All of these typos have been corrected in the following code.
+ */
+
+void A3A8(/* in */ Byte rand[16], /* in */ Byte key[16],
+	/* out */ Byte simoutput[12])
+{
+	Byte x[32], bit[128];
+	int i, j, k, l, m, n, y, z, next_bit;
+
+	/* ( Load RAND into last 16 bytes of input ) */
+	for (i=16; i<32; i++)
+		x[i] = rand[i-16];
+
+	/* ( Loop eight times ) */
+	for (i=1; i<9; i++) {
+		/* ( Load key into first 16 bytes of input ) */
+		for (j=0; j<16; j++)
+			x[j] = key[j];
+		/* ( Perform substitutions ) */
+		for (j=0; j<5; j++)
+			for (k=0; k<(1<<j); k++)
+				for (l=0; l<(1<<(4-j)); l++) {
+					m = l + k*(1<<(5-j));
+					n = m + (1<<(4-j));
+					y = (x[m]+2*x[n]) % (1<<(9-j));
+					z = (2*x[m]+x[n]) % (1<<(9-j));
+					x[m] = table[j][y];
+					x[n] = table[j][z];
+				}
+		/* ( Form bits from bytes ) */
+		for (j=0; j<32; j++)
+			for (k=0; k<4; k++)
+				bit[4*j+k] = (x[j]>>(3-k)) & 1;
+		/* ( Permutation but not on the last loop ) */
+		if (i < 8)
+			for (j=0; j<16; j++) {
+				x[j+16] = 0;
+				for (k=0; k<8; k++) {
+					next_bit = ((8*j + k)*17) % 128;
+					x[j+16] |= bit[next_bit] << (7-k);
+				}
+			}
+	}
+
+	/*
+	 * ( At this stage the vector x[] consists of 32 nibbles.
+	 *   The first 8 of these are taken as the output SRES. )
+	 */
+
+	/* The remainder of the code is not given explicitly in the
+	 * standard, but was derived by reverse-engineering.
+	 */
+
+	for (i=0; i<4; i++)
+		simoutput[i] = (x[2*i]<<4) | x[2*i+1];
+	for (i=0; i<6; i++)
+		simoutput[4+i] = (x[2*i+18]<<6) | (x[2*i+18+1]<<2)
+				| (x[2*i+18+2]>>2);
+	simoutput[4+6] = (x[2*6+18]<<6) | (x[2*6+18+1]<<2);
+	simoutput[4+7] = 0;
+}
+
+
+#ifdef TEST
+int hextoint(char x)
+{
+	x = toupper(x);
+	if (x >= 'A' && x <= 'F')
+		return x-'A'+10;
+	else if (x >= '0' && x <= '9')
+		return x-'0';
+	fprintf(stderr, "bad input.\n");
+	exit(1);
+}
+
+int main(int argc, char **argv)
+{
+	Byte key[16], rand[16], simoutput[12];
+	int i;
+
+	if (argc != 3 || strlen(argv[1]) != 34 || strlen(argv[2]) != 34
+			|| strncmp(argv[1], "0x", 2) != 0
+			|| strncmp(argv[2], "0x", 2) != 0) {
+		fprintf(stderr, "Usage: %s 0x<key> 0x<rand>\n", argv[0]);
+		exit(1);
+	}
+
+	for (i=0; i<16; i++)
+		key[i] = (hextoint(argv[1][2*i+2])<<4)
+			| hextoint(argv[1][2*i+3]);
+	for (i=0; i<16; i++)
+		rand[i] = (hextoint(argv[2][2*i+2])<<4)
+			 | hextoint(argv[2][2*i+3]);
+	A3A8(rand, key, simoutput);
+	printf("simoutput: ");
+	for (i=0; i<12; i++)
+		printf("%02X", simoutput[i]);
+	printf("\n");
+	return 0;
+}
+#endif
+