哈希算法代码如下：
需要导入头文件

#import <CommonCrypto/CommonDigest.h>

然后代码就可以开始了

+ (NSString *)sha1:(NSString *)inputString{
    NSData *data = [inputString dataUsingEncoding:NSUTF8StringEncoding];
    uint8_t digest[CC_SHA1_DIGEST_LENGTH];
    CC_SHA1(data.bytes,(unsigned int)data.length,digest);
    NSMutableString *outputString = [NSMutableString stringWithCapacity:CC_SHA1_DIGEST_LENGTH];
    
    for (int i = 0; i < CC_SHA1_DIGEST_LENGTH; i++) {
        [outputString appendFormat:@"%02x",digest[i]];
    }
    return [outputString lowercaseString];
}