rsa encrypt and decrypt arithmetic source code

丁宏浚
2023-12-01
#include "rsaeuro.h"
#include "r_random.h"
#include "rsa.h"
#include "nn.h"
static int rsapublicfunc PROTO_LIST((unsigned char *, unsigned int *, unsigned char *, unsigned int, R_RSA_PUBLIC_KEY *));
static int rsaprivatefunc PROTO_LIST((unsigned char *, unsigned int *, unsigned char *, unsigned int, R_RSA_PRIVATE_KEY *));
/* RSA encryption, according to RSADSI's PKCS #1. */
int RSAPublicEncrypt(output, outputLen, input, inputLen, publicKey, randomStruct)
unsigned char *output; /* output block */
unsigned int *outputLen; /* length of output block */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
R_RSA_PUBLIC_KEY *publicKey; /* RSA public key */
R_RANDOM_STRUCT *randomStruct; /* random structure */
{
int status;
unsigned char byte, pkcsBlock[MAX_RSA_MODULUS_LEN];
unsigned int i, modulusLen;
modulusLen = (publicKey->bits + 7) / 8;
if(inputLen + 11 > modulusLen)
return(RE_LEN);
*pkcsBlock = 0; /* PKCS Block Makeup */
/* block type 2 */
*(pkcsBlock+1) = 2;
for(i = 2; i < modulusLen - inputLen - 1; i++) {
/* Find nonzero random byte. */
do { /* random bytes used to pad the PKCS Block */
R_GenerateBytes(&byte, 1, randomStruct);
}while(byte == 0);
*(pkcsBlock+i) = byte;
}
/* separator */
pkcsBlock[i++] = 0;
R_memcpy((POINTER)&pkcsBlock[i], (POINTER)input, inputLen);
status = rsapublicfunc(output, outputLen, pkcsBlock, modulusLen, publicKey);
/* Clear sensitive information. */
byte = 0;
R_memset((POINTER)pkcsBlock, 0, sizeof(pkcsBlock));
return(status);
}
/* RSA decryption, according to RSADSI's PKCS #1. */
int RSAPublicDecrypt(output, outputLen, input, inputLen, publicKey)
unsigned char *output; /* output block */
unsigned int *outputLen; /* length of output block */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
R_RSA_PUBLIC_KEY *publicKey; /* RSA public key */
{
int status;
unsigned char pkcsBlock[MAX_RSA_MODULUS_LEN];
unsigned int i, modulusLen, pkcsBlockLen;
modulusLen = (publicKey->bits + 7) / 8;
if(inputLen > modulusLen)
return(RE_LEN);
status = rsapublicfunc(pkcsBlock, &pkcsBlockLen, input, inputLen, publicKey);
if(status)
return(status);
if(pkcsBlockLen != modulusLen)
return(RE_LEN);
/* Require block type 1. */
if((pkcsBlock[0] != 0) || (pkcsBlock[1] != 1))
return(RE_DATA);
for(i = 2; i < modulusLen-1; i++)
if(*(pkcsBlock+i) != 0xff)
break;
/* separator check */
if(pkcsBlock[i++] != 0)
return(RE_DATA);
*outputLen = modulusLen - i;
if(*outputLen + 11 > modulusLen)
return(RE_DATA);
R_memcpy((POINTER)output, (POINTER)&pkcsBlock[i], *outputLen);
/* Clear sensitive information. */
R_memset((POINTER)pkcsBlock, 0, sizeof(pkcsBlock));
return(IDOK);
}
/* RSA encryption, according to RSADSI's PKCS #1. */
int RSAPrivateEncrypt(output, outputLen, input, inputLen, privateKey)
unsigned char *output; /* output block */
unsigned int *outputLen; /* length of output block */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
R_RSA_PRIVATE_KEY *privateKey; /* RSA private key */
{
int status;
unsigned char pkcsBlock[MAX_RSA_MODULUS_LEN];
unsigned int i, modulusLen;
modulusLen = (privateKey->bits + 7) / 8;
if(inputLen + 11 > modulusLen)
return (RE_LEN);
*pkcsBlock = 0;
/* block type 1 */
*(pkcsBlock+1) = 1;
for (i = 2; i < modulusLen - inputLen - 1; i++)
*(pkcsBlock+i) = 0xff;
/* separator */
pkcsBlock[i++] = 0;
R_memcpy((POINTER)&pkcsBlock[i], (POINTER)input, inputLen);
status = rsaprivatefunc(output, outputLen, pkcsBlock, modulusLen, privateKey);
/* Clear sensitive information. */
R_memset((POINTER)pkcsBlock, 0, sizeof(pkcsBlock));
return(status);
}
/* RSA decryption, according to RSADSI's PKCS #1. */
int RSAPrivateDecrypt(output, outputLen, input, inputLen, privateKey)
unsigned char *output; /* output block */
unsigned int *outputLen; /* length of output block */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
R_RSA_PRIVATE_KEY *privateKey; /* RSA private key */
{
int status;
unsigned char pkcsBlock[MAX_RSA_MODULUS_LEN];
unsigned int i, modulusLen, pkcsBlockLen;
modulusLen = (privateKey->bits + 7) / 8;
if(inputLen > modulusLen)
return (RE_LEN);
status = rsaprivatefunc(pkcsBlock, &pkcsBlockLen, input, inputLen, privateKey);
if(status)
return (status);
if(pkcsBlockLen != modulusLen)
return (RE_LEN);
/* We require block type 2. */
if((*pkcsBlock != 0) || (*(pkcsBlock+1) != 2))
return (RE_DATA);
for(i = 2; i < modulusLen-1; i++)
/* separator */
if (*(pkcsBlock+i) == 0)
break;
i++;
if(i >= modulusLen)
return(RE_DATA);
*outputLen = modulusLen - i;
if(*outputLen + 11 > modulusLen)
return(RE_DATA);
R_memcpy((POINTER)output, (POINTER)&pkcsBlock[i], *outputLen);
/* Clear sensitive information. */
R_memset((POINTER)pkcsBlock, 0, sizeof(pkcsBlock));
return(IDOK);
}
/* Raw RSA public-key operation. Output has same length as modulus.
Requires input < modulus.
*/
static int rsapublicfunc(output, outputLen, input, inputLen, publicKey)
unsigned char *output; /* output block */
unsigned int *outputLen; /* length of output block */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
R_RSA_PUBLIC_KEY *publicKey; /* RSA public key */
{
NN_DIGIT c[MAX_NN_DIGITS], e[MAX_NN_DIGITS], m[MAX_NN_DIGITS],
n[MAX_NN_DIGITS];
unsigned int eDigits, nDigits;

/* decode the required RSA function input data */
NN_Decode(m, MAX_NN_DIGITS, input, inputLen);
NN_Decode(n, MAX_NN_DIGITS, publicKey->modulus, MAX_RSA_MODULUS_LEN);
NN_Decode(e, MAX_NN_DIGITS, publicKey->exponent, MAX_RSA_MODULUS_LEN);
nDigits = NN_Digits(n, MAX_NN_DIGITS);
eDigits = NN_Digits(e, MAX_NN_DIGITS);
if(NN_Cmp(m, n, nDigits) >= 0)
return(RE_DATA);
*outputLen = (publicKey->bits + 7) / 8;
/* Compute c = m^e mod n. To perform actual RSA calc.*/
NN_ModExp (c, m, e, eDigits, n, nDigits);
/* encode output to standard form */
NN_Encode (output, *outputLen, c, nDigits);
/* Clear sensitive information. */
R_memset((POINTER)c, 0, sizeof(c));
R_memset((POINTER)m, 0, sizeof(m));
return(IDOK);
}
/* Raw RSA private-key operation. Output has same length as modulus.
Requires input < modulus.
*/
static int rsaprivatefunc(output, outputLen, input, inputLen, privateKey)
unsigned char *output; /* output block */
unsigned int *outputLen; /* length of output block */
unsigned char *input; /* input block */
unsigned int inputLen; /* length of input block */
R_RSA_PRIVATE_KEY *privateKey; /* RSA private key */
{
NN_DIGIT c[MAX_NN_DIGITS], cP[MAX_NN_DIGITS], cQ[MAX_NN_DIGITS],
dP[MAX_NN_DIGITS], dQ[MAX_NN_DIGITS], mP[MAX_NN_DIGITS],
mQ[MAX_NN_DIGITS], n[MAX_NN_DIGITS], p[MAX_NN_DIGITS], q[MAX_NN_DIGITS],
qInv[MAX_NN_DIGITS], t[MAX_NN_DIGITS];
unsigned int cDigits, nDigits, pDigits;
/* decode required input data from standard form */
NN_Decode(c, MAX_NN_DIGITS, input, inputLen); /* input */
/* private key data */
NN_Decode(p, MAX_NN_DIGITS, privateKey->prime[0], MAX_RSA_PRIME_LEN);
NN_Decode(q, MAX_NN_DIGITS, privateKey->prime[1], MAX_RSA_PRIME_LEN);
NN_Decode(dP, MAX_NN_DIGITS, privateKey->primeExponent[0], MAX_RSA_PRIME_LEN);
NN_Decode(dQ, MAX_NN_DIGITS, privateKey->primeExponent[1], MAX_RSA_PRIME_LEN);
NN_Decode(n, MAX_NN_DIGITS, privateKey->modulus, MAX_RSA_MODULUS_LEN);
NN_Decode(qInv, MAX_NN_DIGITS, privateKey->coefficient, MAX_RSA_PRIME_LEN);
/* work out lengths of input components */
cDigits = NN_Digits(c, MAX_NN_DIGITS);
pDigits = NN_Digits(p, MAX_NN_DIGITS);
nDigits = NN_Digits(n, MAX_NN_DIGITS);

if(NN_Cmp(c, n, nDigits) >= 0)
return(RE_DATA);
*outputLen = (privateKey->bits + 7) / 8;
/* Compute mP = cP^dP mod p and mQ = cQ^dQ mod q. (Assumes q has
length at most pDigits, i.e., p > q.)
*/
NN_Mod(cP, c, cDigits, p, pDigits);
NN_Mod(cQ, c, cDigits, q, pDigits);
NN_AssignZero(mP, nDigits);
NN_ModExp(mP, cP, dP, pDigits, p, pDigits);
NN_AssignZero(mQ, nDigits);
NN_ModExp(mQ, cQ, dQ, pDigits, q, pDigits);
/* Chinese Remainder Theorem:
m = ((((mP - mQ) mod p) * qInv) mod p) * q + mQ.
*/
if(NN_Cmp(mP, mQ, pDigits) >= 0) {
NN_Sub(t, mP, mQ, pDigits);
}else{
NN_Sub(t, mQ, mP, pDigits);
NN_Sub(t, p, t, pDigits);
}
NN_ModMult(t, t, qInv, p, pDigits);
NN_Mult(t, t, q, pDigits);
NN_Add(t, t, mQ, nDigits);
/* encode output to standard form */
NN_Encode (output, *outputLen, t, nDigits);
/* Clear sensitive information. */
/*
R_memset((POINTER)c, 0, sizeof(c));
R_memset((POINTER)cP, 0, sizeof(cP));
R_memset((POINTER)cQ, 0, sizeof(cQ));
R_memset((POINTER)dP, 0, sizeof(dP));
R_memset((POINTER)dQ, 0, sizeof(dQ));
R_memset((POINTER)mP, 0, sizeof(mP));
R_memset((POINTER)mQ, 0, sizeof(mQ));
R_memset((POINTER)p, 0, sizeof(p));
R_memset((POINTER)q, 0, sizeof(q));
R_memset((POINTER)qInv, 0, sizeof(qInv));
R_memset((POINTER)t, 0, sizeof(t));
*/
return(IDOK);
}
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