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@@ -80,6 +80,196 @@ int padding_pkcs_15_verify(struct image_sign_info *info,
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return 0;
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}
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+#ifdef CONFIG_FIT_ENABLE_RSASSA_PSS_SUPPORT
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+static void u32_i2osp(uint32_t val, uint8_t *buf)
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+{
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+ buf[0] = (uint8_t)((val >> 24) & 0xff);
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+ buf[1] = (uint8_t)((val >> 16) & 0xff);
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+ buf[2] = (uint8_t)((val >> 8) & 0xff);
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+ buf[3] = (uint8_t)((val >> 0) & 0xff);
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+}
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+
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+/**
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+ * mask_generation_function1() - generate an octet string
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+ *
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+ * Generate an octet string used to check rsa signature.
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+ * It use an input octet string and a hash function.
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+ *
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+ * @checksum: A Hash function
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+ * @seed: Specifies an input variable octet string
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+ * @seed_len: Size of the input octet string
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+ * @output: Specifies the output octet string
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+ * @output_len: Size of the output octet string
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+ * @return 0 if the octet string was correctly generated, others on error
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+ */
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+static int mask_generation_function1(struct checksum_algo *checksum,
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+ uint8_t *seed, int seed_len,
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+ uint8_t *output, int output_len)
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+{
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+ struct image_region region[2];
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+ int ret = 0, i, i_output = 0, region_count = 2;
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+ uint32_t counter = 0;
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+ uint8_t buf_counter[4], *tmp;
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+ int hash_len = checksum->checksum_len;
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+
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+ memset(output, 0, output_len);
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+
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+ region[0].data = seed;
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+ region[0].size = seed_len;
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+ region[1].data = &buf_counter[0];
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+ region[1].size = 4;
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+
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+ tmp = malloc(hash_len);
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+ if (!tmp) {
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+ debug("%s: can't allocate array tmp\n", __func__);
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+ ret = -ENOMEM;
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+ goto out;
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+ }
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+
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+ while (i_output < output_len) {
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+ u32_i2osp(counter, &buf_counter[0]);
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+
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+ ret = checksum->calculate(checksum->name,
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+ region, region_count,
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+ tmp);
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+ if (ret < 0) {
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+ debug("%s: Error in checksum calculation\n", __func__);
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+ goto out;
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+ }
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+
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+ i = 0;
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+ while ((i_output < output_len) && (i < hash_len)) {
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+ output[i_output] = tmp[i];
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+ i_output++;
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+ i++;
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+ }
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+
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+ counter++;
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+ }
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+
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+out:
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+ free(tmp);
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+
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+ return ret;
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+}
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+
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+static int compute_hash_prime(struct checksum_algo *checksum,
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+ uint8_t *pad, int pad_len,
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+ uint8_t *hash, int hash_len,
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+ uint8_t *salt, int salt_len,
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+ uint8_t *hprime)
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+{
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+ struct image_region region[3];
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+ int ret, region_count = 3;
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+
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+ region[0].data = pad;
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+ region[0].size = pad_len;
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+ region[1].data = hash;
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+ region[1].size = hash_len;
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+ region[2].data = salt;
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+ region[2].size = salt_len;
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+
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+ ret = checksum->calculate(checksum->name, region, region_count, hprime);
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+ if (ret < 0) {
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+ debug("%s: Error in checksum calculation\n", __func__);
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+ goto out;
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+ }
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+
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+out:
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+ return ret;
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+}
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+
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+int padding_pss_verify(struct image_sign_info *info,
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+ uint8_t *msg, int msg_len,
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+ const uint8_t *hash, int hash_len)
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+{
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+ uint8_t *masked_db = NULL;
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+ int masked_db_len = msg_len - hash_len - 1;
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+ uint8_t *h = NULL, *hprime = NULL;
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+ int h_len = hash_len;
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+ uint8_t *db_mask = NULL;
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+ int db_mask_len = masked_db_len;
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+ uint8_t *db = NULL, *salt = NULL;
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+ int db_len = masked_db_len, salt_len = msg_len - hash_len - 2;
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+ uint8_t pad_zero[8] = { 0 };
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+ int ret, i, leftmost_bits = 1;
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+ uint8_t leftmost_mask;
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+ struct checksum_algo *checksum = info->checksum;
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+
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+ /* first, allocate everything */
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+ masked_db = malloc(masked_db_len);
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+ h = malloc(h_len);
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+ db_mask = malloc(db_mask_len);
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+ db = malloc(db_len);
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+ salt = malloc(salt_len);
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+ hprime = malloc(hash_len);
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+ if (!masked_db || !h || !db_mask || !db || !salt || !hprime) {
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+ printf("%s: can't allocate some buffer\n", __func__);
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+ ret = -ENOMEM;
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+ goto out;
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+ }
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+
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+ /* step 4: check if the last byte is 0xbc */
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+ if (msg[msg_len - 1] != 0xbc) {
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+ printf("%s: invalid pss padding (0xbc is missing)\n", __func__);
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+ ret = -EINVAL;
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+ goto out;
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+ }
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+
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+ /* step 5 */
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+ memcpy(masked_db, msg, masked_db_len);
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+ memcpy(h, msg + masked_db_len, h_len);
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+
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+ /* step 6 */
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+ leftmost_mask = (0xff >> (8 - leftmost_bits)) << (8 - leftmost_bits);
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+ if (masked_db[0] & leftmost_mask) {
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+ printf("%s: invalid pss padding ", __func__);
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+ printf("(leftmost bit of maskedDB not zero)\n");
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+ ret = -EINVAL;
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+ goto out;
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+ }
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+
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+ /* step 7 */
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+ mask_generation_function1(checksum, h, h_len, db_mask, db_mask_len);
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+
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+ /* step 8 */
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+ for (i = 0; i < db_len; i++)
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+ db[i] = masked_db[i] ^ db_mask[i];
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+
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+ /* step 9 */
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+ db[0] &= 0xff >> leftmost_bits;
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+
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+ /* step 10 */
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+ if (db[0] != 0x01) {
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+ printf("%s: invalid pss padding ", __func__);
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+ printf("(leftmost byte of db isn't 0x01)\n");
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+ ret = EINVAL;
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+ goto out;
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+ }
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+
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+ /* step 11 */
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+ memcpy(salt, &db[1], salt_len);
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+
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+ /* step 12 & 13 */
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+ compute_hash_prime(checksum, pad_zero, 8,
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+ (uint8_t *)hash, hash_len,
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+ salt, salt_len, hprime);
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+
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+ /* step 14 */
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+ ret = memcmp(h, hprime, hash_len);
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+
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+out:
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+ free(hprime);
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+ free(salt);
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+ free(db);
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+ free(db_mask);
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+ free(h);
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+ free(masked_db);
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+
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+ return ret;
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+}
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+#endif
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+
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/**
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* rsa_verify_key() - Verify a signature against some data using RSA Key
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*
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