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implement peer review feedback

pull/189/head
kaleb-himes 2020-02-26 10:13:39 -07:00
parent 5404a201fa
commit c1e3cdd5d7
2 changed files with 23 additions and 5 deletions
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2
signature/ecc-sign-verify/README.md
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@ -1,6 +1,6 @@
# Signature Test Example
Demonstrates using a hash digest to sign and verify a signature using RSA
Demonstrates using a hash digest to sign and verify a signature using ECC
## Building

26
signature/ecc-sign-verify/ecc_sign_verify.c
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@ -91,15 +91,33 @@ finished:
int do_sig_ver_test(int eccKeySz)
{
int ret;
unsigned char hash[32] = "A 32-bit string to test signing";
/* sha256 hash of the string "A 32-bit string to test signing" */
unsigned char hash[32] = {
0x3b, 0x07, 0x54, 0x5c, 0xfd, 0x4f, 0xb7, 0xb5,
0xaf, 0xa7, 0x7a, 0x25, 0x33, 0xa5, 0x50, 0x70,
0x4a, 0x65, 0x3e, 0x72, 0x7e, 0xcd, 0xd4, 0x5b,
0x1b, 0x36, 0x96, 0x96, 0xca, 0x4f, 0x9b, 0x6f
};
ecc_key key;
byte* sig = NULL; // get rid of this magic number
WC_RNG rng;
int verified = 0;
/* for odd curve sizes account for mod EG (256/8) + (256%8) == 32 + 0 = 32
* alternatively (521/8 = 65.125 (rounds to 65) + (521%8) == 65 + 1 = 66
/*
* for odd curve sizes account for mod EG:
* Case 1) curve field of 256:
* (256/8) + (256%8 != 0 ? 1:0) == 32 + 0 = 32
*
* Case 2) curve field of 521:
* (521/8 = 65.125 (rounds to 65) + (521%8 != 0 ? 1:0) ==
65 + 1 = 66
*
* Algorithm: (C / B) + (C % B != 0 ? 1:0)
*
* This remainder is a natural result of the calculation:
* Algorithm: (C / (B-1)) / (B)
*/
int byteField = (eccKeySz / BYTE_SZ) + (((eccKeySz % BYTE_SZ) != 0) ? 1:0);
int byteField = (eccKeySz + (BYTE_SZ - 1)) / BYTE_SZ;
word32 maxSigSz = ECC_MAX_SIG_SIZE;
printf("Key size is %d, byteField = %d\n", eccKeySz, byteField);