MD5需用到#import <CommonCrypto/CommonHMAC.h>

• MD5加密32位

+ (NSString *)hMacMD5String:(NSString *)string{

    const char *original_str = [string UTF8String];
    unsigned char result[CC_MD5_DIGEST_LENGTH];
    
    CC_MD5(original_str, (unsigned int)strlen(original_str), result);
    NSMutableString *hash = [NSMutableString new];
    
    for (int i = 0; i < CC_MD5_DIGEST_LENGTH; i++){
        [hash appendFormat:@"%02X", result[i]];
    }
    
    NSString *mdfiveString = [hash uppercaseString];
    return mdfiveString;
}

• HmacMD5加密，使用秘钥。

+ (NSString *)hMacMD5String:(NSString *)string Key:(NSString *)keyStr
{
    const char *cKey  = [keyStr cStringUsingEncoding:NSUTF8StringEncoding];
    const char *cData = [string cStringUsingEncoding:NSUTF8StringEncoding];
    const unsigned int blockSize = 64;
    char ipad[blockSize];
    char opad[blockSize];
    char keypad[blockSize];
    
    unsigned int keyLen = (unsigned int)strlen(cKey);
    CC_MD5_CTX ctxt;
    if (keyLen > blockSize) {
        CC_MD5_Init(&ctxt);
        CC_MD5_Update(&ctxt, cKey, keyLen);
        CC_MD5_Final((unsigned char *)keypad, &ctxt);
        keyLen = CC_MD5_DIGEST_LENGTH;
    }
    else {
        memcpy(keypad, cKey, keyLen);
    }
    
    memset(ipad, 0x36, blockSize);
    memset(opad, 0x5c, blockSize);
    
    int i;
    for (i = 0; i < keyLen; i++) {
        ipad[i] ^= keypad[i];
        opad[i] ^= keypad[i];
    }
    
    CC_MD5_Init(&ctxt);
    CC_MD5_Update(&ctxt, ipad, blockSize);
    CC_MD5_Update(&ctxt, cData, (CC_LONG)strlen(cData));
    unsigned char md5[CC_MD5_DIGEST_LENGTH];
    CC_MD5_Final(md5, &ctxt);
    
    CC_MD5_Init(&ctxt);
    CC_MD5_Update(&ctxt, opad, blockSize);
    CC_MD5_Update(&ctxt, md5, CC_MD5_DIGEST_LENGTH);
    CC_MD5_Final(md5, &ctxt);
    
    const unsigned int hex_len = CC_MD5_DIGEST_LENGTH*2+2;
    char hex[hex_len];
    for(i = 0; i < CC_MD5_DIGEST_LENGTH; i++) {
        snprintf(&hex[i*2], hex_len-i*2, "%02x", md5[i]);
    }
    
    NSData *HMAC = [[NSData alloc] initWithBytes:hex length:strlen(hex)];
    NSString *hash = [[NSString alloc] initWithData:HMAC encoding:NSUTF8StringEncoding];
    return hash;
}