--- /dev/null
+../../../licenses/BSD-MIT
\ No newline at end of file
--- /dev/null
+#include "config.h"
+#include <stdio.h>
+#include <string.h>
+
+/**
+ * crypto/hkdf_sha256 - RFC5869 Hardened Key Derivation Functions using SHA256
+ *
+ * This code implements the hkdf described in RFC5869.
+ *
+ * License: BSD-MIT
+ * Maintainer: Rusty Russell <rusty@rustcorp.com.au>
+ */
+int main(int argc, char *argv[])
+{
+ /* Expect exactly one argument */
+ if (argc != 2)
+ return 1;
+
+ if (strcmp(argv[1], "depends") == 0) {
+ printf("ccan/crypto/hmac_sha256\n");
+ return 0;
+ }
+
+ if (strcmp(argv[1], "testdepends") == 0) {
+ printf("ccan/str/hex\n");
+ return 0;
+ }
+
+ return 1;
+}
--- /dev/null
+/* MIT (BSD) license - see LICENSE file for details */
+#include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
+#include <ccan/crypto/hmac_sha256/hmac_sha256.h>
+#include <assert.h>
+#include <string.h>
+
+void hkdf_sha256(unsigned char *okm, size_t okm_size,
+ const void *s, size_t ssize,
+ const void *k, size_t ksize,
+ const void *info, size_t isize)
+{
+ struct hmac_sha256 prk, t;
+ struct hmac_sha256_ctx ctx;
+ unsigned char c;
+
+ assert(okm_size < 255 * sizeof(t));
+
+ /* RFC 5869:
+ *
+ * 2.2. Step 1: Extract
+ *
+ * HKDF-Extract(salt, IKM) -> PRK
+ *
+ * Options:
+ * Hash a hash function; HashLen denotes the length of the
+ * hash function output in octets
+ *
+ * Inputs:
+ * salt optional salt value (a non-secret random value);
+ * if not provided, it is set to a string of HashLen zeros.
+ * IKM input keying material
+ *
+ * Output:
+ * PRK a pseudorandom key (of HashLen octets)
+ *
+ * The output PRK is calculated as follows:
+ *
+ * PRK = HMAC-Hash(salt, IKM)
+ */
+ hmac_sha256(&prk, s, ssize, k, ksize);
+
+ /*
+ * 2.3. Step 2: Expand
+ *
+ * HKDF-Expand(PRK, info, L) -> OKM
+ *
+ * Options:
+ * Hash a hash function; HashLen denotes the length of the
+ * hash function output in octets
+ *
+ * Inputs:
+ * PRK a pseudorandom key of at least HashLen octets
+ * (usually, the output from the extract step)
+ * info optional context and application specific information
+ * (can be a zero-length string)
+ * L length of output keying material in octets
+ * (<= 255*HashLen)
+ *
+ * Output:
+ * OKM output keying material (of L octets)
+ *
+ * The output OKM is calculated as follows:
+ *
+ * N = ceil(L/HashLen)
+ * T = T(1) | T(2) | T(3) | ... | T(N)
+ * OKM = first L octets of T
+ *
+ * where:
+ * T(0) = empty string (zero length)
+ * T(1) = HMAC-Hash(PRK, T(0) | info | 0x01)
+ * T(2) = HMAC-Hash(PRK, T(1) | info | 0x02)
+ * T(3) = HMAC-Hash(PRK, T(2) | info | 0x03)
+ * ...
+ *
+ * (where the constant concatenated to the end of each T(n) is a
+ * single octet.)
+ */
+ c = 1;
+ hmac_sha256_init(&ctx, &prk, sizeof(prk));
+ hmac_sha256_update(&ctx, info, isize);
+ hmac_sha256_update(&ctx, &c, 1);
+ hmac_sha256_done(&ctx, &t);
+
+ while (okm_size > sizeof(t)) {
+ memcpy(okm, &t, sizeof(t));
+ okm += sizeof(t);
+ okm_size -= sizeof(t);
+
+ c++;
+ hmac_sha256_init(&ctx, &prk, sizeof(prk));
+ hmac_sha256_update(&ctx, &t, sizeof(t));
+ hmac_sha256_update(&ctx, info, isize);
+ hmac_sha256_update(&ctx, &c, 1);
+ hmac_sha256_done(&ctx, &t);
+ }
+ memcpy(okm, &t, okm_size);
+}
--- /dev/null
+#ifndef CCAN_CRYPTO_HKDF_SHA256_H
+#define CCAN_CRYPTO_HKDF_SHA256_H
+/* BSD-MIT - see LICENSE file for details */
+#include "config.h"
+#include <stdlib.h>
+
+/**
+ * hkdf_sha256 - generate a derived key
+ * @okm: where to output the key
+ * @okm_size: the number of bytes pointed to by @okm (must be less than 255*32)
+ * @s: salt
+ * @ssize: the number of bytes pointed to by @s
+ * @k: pointer to input key
+ * @ksize: the number of bytes pointed to by @k
+ * @info: pointer to info
+ * @isize: the number of bytes pointed to by @info
+ */
+void hkdf_sha256(unsigned char *okm, size_t okm_size,
+ const void *s, size_t ssize,
+ const void *k, size_t ksize,
+ const void *info, size_t isize);
+#endif /* CCAN_CRYPTO_HKDF_SHA256_H */
--- /dev/null
+/* From RFC5869 Appendix A
+ *
+ * https://tools.ietf.org/html/rfc5869
+ */
+#include <ccan/crypto/hkdf_sha256/hkdf_sha256.h>
+#include <ccan/tap/tap.h>
+#include <ccan/str/hex/hex.h>
+#include <string.h>
+#include <assert.h>
+
+struct test {
+ const char *ikm, *salt, *info, *okm;
+};
+
+static struct test tests[] = { {
+ /* Test Case 1
+ Basic test case with SHA-256
+ */
+ "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b", /* (22 octets) */
+ "000102030405060708090a0b0c", /* (13 octets) */
+ "f0f1f2f3f4f5f6f7f8f9", /* (10 octets) */
+ "3cb25f25faacd57a90434f64d0362f2a2d2d0a90cf1a5a4c5db02d56ecc4c5bf34007208d5b887185865", /* (42 octets) */
+ },
+ {
+ /* Test Case 2
+ *
+ * Test with SHA-256 and longer inputs/outputs */
+ "000102030405060708090a0b0c0d0e0f"
+ "101112131415161718191a1b1c1d1e1f"
+ "202122232425262728292a2b2c2d2e2f"
+ "303132333435363738393a3b3c3d3e3f"
+ "404142434445464748494a4b4c4d4e4f", /* (80 octets) */
+ "606162636465666768696a6b6c6d6e6f"
+ "707172737475767778797a7b7c7d7e7f"
+ "808182838485868788898a8b8c8d8e8f"
+ "909192939495969798999a9b9c9d9e9f"
+ "a0a1a2a3a4a5a6a7a8a9aaabacadaeaf", /* (80 octets )*/
+ "b0b1b2b3b4b5b6b7b8b9babbbcbdbebf"
+ "c0c1c2c3c4c5c6c7c8c9cacbcccdcecf"
+ "d0d1d2d3d4d5d6d7d8d9dadbdcdddedf"
+ "e0e1e2e3e4e5e6e7e8e9eaebecedeeef"
+ "f0f1f2f3f4f5f6f7f8f9fafbfcfdfeff", /* (80 octets) */
+ "b11e398dc80327a1c8e7f78c596a4934"
+ "4f012eda2d4efad8a050cc4c19afa97c"
+ "59045a99cac7827271cb41c65e590e09"
+ "da3275600c2f09b8367793a9aca3db71"
+ "cc30c58179ec3e87c14c01d5c1f3434f"
+ "1d87" /* (82 octets) */
+ },
+ {
+ /* Test Case 3
+ *
+ * Test with SHA-256 and zero-length salt/info
+ */
+ "0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b0b", /* (22 octets) */
+ "", /* (0 octets) */
+ "", /* (0 octets) */
+ "8da4e775a563c18f715f802a063c5a31"
+ "b8a11f5c5ee1879ec3454e5f3c738d2d"
+ "9d201395faa4b61a96c8" /* (42 octets) */
+ }
+};
+
+static void *fromhex(const char *str, size_t *len)
+{
+ void *p;
+
+ *len = hex_data_size(strlen(str));
+ p = malloc(*len);
+ if (!hex_decode(str, strlen(str), p, *len))
+ abort();
+ return p;
+}
+
+int main(void)
+{
+ size_t i;
+
+ plan_tests(sizeof(tests) / sizeof(tests[0]));
+
+ for (i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) {
+ size_t ksize, ssize, isize, okmsize;
+ void *k, *s, *info, *expect, *okm;
+
+ k = fromhex(tests[i].ikm, &ksize);
+ s = fromhex(tests[i].salt, &ssize);
+ info = fromhex(tests[i].info, &isize);
+ expect = fromhex(tests[i].okm, &okmsize);
+ okm = malloc(okmsize);
+ hkdf_sha256(okm, okmsize, s, ssize, k, ksize, info, isize);
+ ok1(memcmp(okm, expect, okmsize) == 0);
+
+ free(k);
+ free(s);
+ free(info);
+ free(expect);
+ free(okm);
+ }
+
+ return exit_status();
+}