BnMath.c -Msb - Lsb-java转换

   public static  String  convertMsb(String S){
        LinkedList queue = new LinkedList();
        int length = S.length()/2;

        for (int i = 0; i < length; i++) {
            String ss = S.substring(0,2);
            queue.addFirst(ss);
            S = S.substring(2);
        }

        String join = String.join("", queue);
       return join;
    }

测试一下：

   @Test
    public void test2() {
        String   S = "63720228582810F7595D38FEFD839935A76197DC31ABB3CB2EA5FF5A61A89D13DA89BB67CEAD92FAA8CA21A94D8C2B80D3ADE7F99938C5EDDD404F972FC5EC950ECCBBDA28F9D6FBCB7195E321055467DB64C31C367E07D3B7CF399CE8D083A4DC6297FD77E79F2F94B50856FA3F411BAA58A53EA054F9DDA5CC46DD0340D7CC";

        // 转换成 ccd74003dd46cca5ddf954a03ea558aa1b413ffa5608b5942f9fe777fd9762dca483d0e89c39cfb7d3077e361cc364db67540521e39571cbfbd6f928dabbcc0e95ecc52f974f40ddedc53899f9e7add3802b8c4da921caa8fa92adce67bb89da139da8615affa52ecbb3ab31dc9761a7359983fdfe385d59f710285828027263
        String s = convertMsb(S);
        System.out.println("s = " + s);
    }

走该分支

    e = publicArea->parameters.rsaDetail.exponent;
    if(e == 0)
        e = RSA_DEFAULT_PUBLIC_EXPONENT;

e= 65537

 

 keySizeInBits = publicArea->parameters.rsaDetail.keyBits; 

2048

 

LIB_EXPORT int
Msb(
    crypt_uword_t           word
    )
{
    int             retVal = -1;
    //
#if RADIX_BITS == 64
    if(word & 0xffffffff00000000) { retVal += 32; word >>= 32; }
#endif
    if(word & 0xffff0000) { retVal += 16; word >>= 16; }
    if(word & 0x0000ff00) { retVal += 8; word >>= 8; }
    if(word & 0x000000f0) { retVal += 4; word >>= 4; }
    if(word & 0x0000000c) { retVal += 2; word >>= 2; }
    if(word & 0x00000002) { retVal += 1; word >>= 1; }
    return retVal + (int)word;
}

BnMath.c

LIB_EXPORT int
BnLsb(
    bigConst            bn
);