Objective-Cでハッシュ関数使う必要が出てきたので調べてみた。 -(NSString*) sha256:(NSString *)text{ const char *s=[text cStringUsingEncoding:NSASCIIStringEncoding]; NSData *keyData=[NSData dataWithBytes:s length:strlen(s)]; uint8_t digest[CC_SHA256_DIGEST_LENGTH]={0}; CC_SHA256(keyData.bytes, keyData.length, digest); NSData *out = [NSData dataWithBytes:digest length:CC_SHA256_DIGEST_LENGTH]; NSString *hash=[out description