hmac－sha1算法_zju_bigjar的专栏

+ (NSString *)hmac_sha1:(NSString *)plaintext withKey:(NSString *)key
{
    NSData *cKey  = [self hexStringToNSData:key];  //key转换为二进制数据
    const char *cData = [plaintext cStringUsingEncoding:NSUTF8StringEncoding];
    
    uint8_t cHMAC[CC_SHA1_DIGEST_LENGTH];
    
    CCHmac(kCCHmacAlgSHA1, [cKey bytes], cKey.length, cData, strlen(cData), cHMAC);  //hmac
    
    NSString *hash;
    NSMutableString* output = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH * 2];
    for(int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++)  //转换到output
        [output appendFormat:@"%02x", cHMAC[i]];
    hash = output;
    
    return hash;
}+ (NSString *)hmac_sha1:(NSString *)plaintext w