如何在 iOS 中计算 SHA-2(最好是 SHA 256 或 SHA 512)哈希? [英] How can I compute a SHA-2 (ideally SHA 256 or SHA 512) hash in iOS?

问题描述

安全服务 API 似乎不允许我直接计算哈希.有很多可用的公共领域和自由许可版本，但如果可能，我宁愿使用系统库实现.

The Security services API doesn't appear to allow me to compute a hash directly. There are plenty of public domain and liberally licensed versions available, but I'd rather use a system library implementation if possible.

可以通过 NSData 或普通指针访问数据.

The data is accessible via NSData, or plain pointers.

散列的加密强度对我很重要.SHA-256 是可接受的最小哈希大小.

The cryptographic strength of the hash is important to me. SHA-256 is the minimum acceptable hash size.

推荐答案

这是我用于 SHA1 的内容:

This is what I'm using for SHA1:

#import <CommonCrypto/CommonDigest.h>

+ (NSData *)sha1:(NSData *)data {
    unsigned char hash[CC_SHA1_DIGEST_LENGTH];
    if ( CC_SHA1([data bytes], [data length], hash) ) {
        NSData *sha1 = [NSData dataWithBytes:hash length:CC_SHA1_DIGEST_LENGTH];        
        return sha1;
    }
return nil;
}

将 CC_SHA1 替换为 CC_SHA256(或您需要的任何一个)，以及将 CC_SHA1_DIGEST_LENGTH 替换为 CC_SHA256_DIGEST_LENGTH.

Replace CC_SHA1 with CC_SHA256 (or whichever you need), as well as CC_SHA1_DIGEST_LENGTH with CC_SHA256_DIGEST_LENGTH.

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