sha3.[hc]: add kmac256_xof_{init,absorb,squeeze,once}() and test_kmac256_xof()

2 files changed, 186 insertions, 0 deletions

diff --git a/sha3.c b/sha3.c
index 74bca26..9097da2 100644
--- a/sha3.c
+++ b/sha3.c
@@ -839,6 +839,64 @@ void kmac128_xof_once(const kmac_params_t params, const uint8_t * const src, con
   kmac128_xof_squeeze(&xof, dst, dst_len);
 }
 
+_Bool kmac256_xof_absorb(sha3_xof_t * const xof, const uint8_t * const msg, const size_t len) {
+  return cshake256_xof_absorb(xof, msg, len);
+}
+
+void kmac256_xof_squeeze(sha3_xof_t * const xof, uint8_t * const dst, const size_t len) {
+  if (!xof->squeezing) {
+    // append XOF length suffix
+    const uint8_t SUFFIX[] = { 0, 1 };
+    (void) cshake256_xof_absorb(xof, SUFFIX, sizeof(SUFFIX));
+  }
+  cshake256_xof_squeeze(xof, dst, len);
+}
+
+void kmac256_xof_init(sha3_xof_t * const xof, const kmac_params_t params) {
+  static const uint8_t PAD[CSHAKE256_XOF_RATE] = { 0 };
+  static const uint8_t NAME[4] = { 'K', 'M', 'A', 'C' };
+
+  // build cshake256 params
+  const cshake_params_t cshake_params = {
+    .name = NAME,
+    .name_len = sizeof(NAME),
+    .custom = params.custom,
+    .custom_len = params.custom_len,
+  };
+
+  // build key prefix
+  uint8_t key_buf[9] = { 0 };
+  const size_t key_buf_len = encode_string_prefix(key_buf, params.key_len);
+
+  // build bytepad prefix
+  const bytepad_t bp = bytepad(key_buf_len + params.key_len, CSHAKE256_XOF_RATE);
+
+  // init xof
+  cshake256_xof_init(xof, cshake_params);
+
+  // absorb bytepad prefix
+  (void) cshake256_xof_absorb(xof, bp.prefix, bp.prefix_len);
+
+  // absorb key
+  (void) cshake256_xof_absorb(xof, key_buf, key_buf_len);
+  if (params.key_len > 0) {
+    (void) cshake256_xof_absorb(xof, params.key, params.key_len);
+  }
+
+  // absorb padding
+  for (size_t ofs = 0; ofs < bp.pad_len; ofs += sizeof(PAD)) {
+    const size_t len = MIN(bp.pad_len - ofs, sizeof(PAD));
+    (void) cshake256_xof_absorb(xof, PAD, len);
+  }
+}
+
+void kmac256_xof_once(const kmac_params_t params, const uint8_t * const src, const size_t src_len, uint8_t * const dst, const size_t dst_len) {
+  sha3_xof_t xof;
+  kmac256_xof_init(&xof, params);
+  kmac256_xof_absorb(&xof, src, src_len);
+  kmac256_xof_squeeze(&xof, dst, dst_len);
+}
+
 #ifdef SHA3_TEST
 #include <stdio.h> // printf()
 
@@ -2945,6 +3003,128 @@ static void test_kmac128_xof(void) {
   }
 }
 
+static void test_kmac256_xof(void) {
+  static const struct {
+    const char *name; // test name
+    const uint8_t key[256]; // key
+    const size_t key_len; // key length
+    const uint8_t custom[256]; // custom name
+    const size_t custom_len; // custom name length
+    const uint8_t msg[256]; // test message
+    const size_t len; // test message length
+    const size_t dst_len; // output length
+    const uint8_t exp[64]; // expected hash
+  } tests[] = {{
+    // https://csrc.nist.gov/CSRC/media/Projects/Cryptographic-Standards-and-Guidelines/documents/examples/KMACXOF_samples.pdf
+    .name = "KMACXOF Sample #4",
+    .key = {
+      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+      0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+      0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+    },
+    .key_len = 32,
+    .custom = "My Tagged Application",
+    .custom_len = 21,
+    .msg = { 0, 1, 2, 3 },
+    .len = 4,
+    .exp = {
+      0x17, 0x55, 0x13, 0x3F, 0x15, 0x34, 0x75, 0x2A, 0xAD, 0x07, 0x48, 0xF2, 0xC7, 0x06, 0xFB, 0x5C,
+      0x78, 0x45, 0x12, 0xCA, 0xB8, 0x35, 0xCD, 0x15, 0x67, 0x6B, 0x16, 0xC0, 0xC6, 0x64, 0x7F, 0xA9,
+      0x6F, 0xAA, 0x7A, 0xF6, 0x34, 0xA0, 0xBF, 0x8F, 0xF6, 0xDF, 0x39, 0x37, 0x4F, 0xA0, 0x0F, 0xAD,
+      0x9A, 0x39, 0xE3, 0x22, 0xA7, 0xC9, 0x20, 0x65, 0xA6, 0x4E, 0xB1, 0xFB, 0x08, 0x01, 0xEB, 0x2B,
+    },
+  }, {
+    .name = "KMACXOF Sample #5",
+    .key = {
+      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+      0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+      0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+    },
+    .key_len = 32,
+    .custom = "",
+    .custom_len = 0,
+    .msg = {
+      0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
+      0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
+      0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
+      0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
+      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+      0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
+      0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
+      0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
+      0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
+      0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
+      0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
+      0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7,
+    },
+    .len = 200,
+    .exp = {
+      0xFF, 0x7B, 0x17, 0x1F, 0x1E, 0x8A, 0x2B, 0x24, 0x68, 0x3E, 0xED, 0x37, 0x83, 0x0E, 0xE7, 0x97,
+      0x53, 0x8B, 0xA8, 0xDC, 0x56, 0x3F, 0x6D, 0xA1, 0xE6, 0x67, 0x39, 0x1A, 0x75, 0xED, 0xC0, 0x2C,
+      0xA6, 0x33, 0x07, 0x9F, 0x81, 0xCE, 0x12, 0xA2, 0x5F, 0x45, 0x61, 0x5E, 0xC8, 0x99, 0x72, 0x03,
+      0x1D, 0x18, 0x33, 0x73, 0x31, 0xD2, 0x4C, 0xEB, 0x8F, 0x8C, 0xA8, 0xE6, 0xA1, 0x9F, 0xD9, 0x8B,
+    },
+  }, {
+    .name = "KMACXOF Sample #6",
+    .key = {
+      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+      0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57,
+      0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+    },
+    .key_len = 32,
+    .custom = "My Tagged Application",
+    .custom_len = 21,
+    .msg = {
+      0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0A, 0x0B, 0x0C, 0x0D, 0x0E, 0x0F,
+      0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18, 0x19, 0x1A, 0x1B, 0x1C, 0x1D, 0x1E, 0x1F,
+      0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2A, 0x2B, 0x2C, 0x2D, 0x2E, 0x2F,
+      0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3A, 0x3B, 0x3C, 0x3D, 0x3E, 0x3F,
+      0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49, 0x4A, 0x4B, 0x4C, 0x4D, 0x4E, 0x4F,
+      0x50, 0x51, 0x52, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5A, 0x5B, 0x5C, 0x5D, 0x5E, 0x5F,
+      0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6A, 0x6B, 0x6C, 0x6D, 0x6E, 0x6F,
+      0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79, 0x7A, 0x7B, 0x7C, 0x7D, 0x7E, 0x7F,
+      0x80, 0x81, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8A, 0x8B, 0x8C, 0x8D, 0x8E, 0x8F,
+      0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9A, 0x9B, 0x9C, 0x9D, 0x9E, 0x9F,
+      0xA0, 0xA1, 0xA2, 0xA3, 0xA4, 0xA5, 0xA6, 0xA7, 0xA8, 0xA9, 0xAA, 0xAB, 0xAC, 0xAD, 0xAE, 0xAF,
+      0xB0, 0xB1, 0xB2, 0xB3, 0xB4, 0xB5, 0xB6, 0xB7, 0xB8, 0xB9, 0xBA, 0xBB, 0xBC, 0xBD, 0xBE, 0xBF,
+      0xC0, 0xC1, 0xC2, 0xC3, 0xC4, 0xC5, 0xC6, 0xC7,
+    },
+    .len = 200,
+    .exp = {
+      0xD5, 0xBE, 0x73, 0x1C, 0x95, 0x4E, 0xD7, 0x73, 0x28, 0x46, 0xBB, 0x59, 0xDB, 0xE3, 0xA8, 0xE3,
+      0x0F, 0x83, 0xE7, 0x7A, 0x4B, 0xFF, 0x44, 0x59, 0xF2, 0xF1, 0xC2, 0xB4, 0xEC, 0xEB, 0xB8, 0xCE,
+      0x67, 0xBA, 0x01, 0xC6, 0x2E, 0x8A, 0xB8, 0x57, 0x8D, 0x2D, 0x49, 0x9B, 0xD1, 0xBB, 0x27, 0x67,
+      0x68, 0x78, 0x11, 0x90, 0x02, 0x0A, 0x30, 0x6A, 0x97, 0xDE, 0x28, 0x1D, 0xCC, 0x30, 0x30, 0x5D,
+    },
+  }};
+
+  for (size_t i = 0; i < sizeof(tests) / sizeof(tests[0]); i++) {
+    const kmac_params_t params = {
+      .key = tests[i].key,
+      .key_len = tests[i].key_len,
+      .custom = tests[i].custom,
+      .custom_len = tests[i].custom_len,
+    };
+
+    // run
+    uint8_t got[64];
+    kmac256_xof_once(params, tests[i].msg, tests[i].len, got, sizeof(got));
+
+    // check
+    if (memcmp(got, tests[i].exp, sizeof(got))) {
+      fprintf(stderr, "test_kmac256_xof(\"%s\") failed, got:\n", tests[i].name);
+      dump_hex(stderr, got, 32);
+
+      fprintf(stderr, "exp:\n");
+      dump_hex(stderr, tests[i].exp, 32);
+    }
+  }
+}
+
 int main(void) {
   test_theta();
   test_rho();
@@ -2971,6 +3151,7 @@ int main(void) {
   test_kmac128();
   test_kmac256();
   test_kmac128_xof();
+  test_kmac256_xof();
   printf("ok\n");
 }
 
diff --git a/sha3.h b/sha3.h
index e5025ff..a2014c9 100644
--- a/sha3.h
+++ b/sha3.h
@@ -69,6 +69,11 @@ _Bool kmac128_xof_absorb(sha3_xof_t * const xof, const uint8_t * const msg, cons
 void kmac128_xof_squeeze(sha3_xof_t * const xof, uint8_t * const dst, const size_t len);
 void kmac128_xof_once(const kmac_params_t params, const uint8_t * const src, const size_t src_len, uint8_t * const dst, const size_t dst_len);
 
+void kmac256_xof_init(sha3_xof_t * const xof, const kmac_params_t params);
+_Bool kmac256_xof_absorb(sha3_xof_t * const xof, const uint8_t * const msg, const size_t len);
+void kmac256_xof_squeeze(sha3_xof_t * const xof, uint8_t * const dst, const size_t len);
+void kmac256_xof_once(const kmac_params_t params, const uint8_t * const src, const size_t src_len, uint8_t * const dst, const size_t dst_len);
+
 #ifdef __cplusplus
 }
 #endif /* __cplusplus */