怎样在C中用openssl解码php中base64_encode的编码？

sugelawa

php中base64_encode编码的结果怎么与openssl的base64编码结果不一样：

1. <?php
   
2. echo base64_encode("aaa");
   
3. ?>
   
4. 
   
5. result is "YWFh"

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用openssl命令行测试：

1. #echo "aaa" | openssl enc -base64
   
2. output: YWFhCg==
   
3. 
   
4. #echo "YWFhCg==" | openssl enc -base64 -d
   
5. output: aaa

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为什么一个是"YWFh"，而另一个是"YWFhCg=="?
我本来想在C中这样解码，但是结果是NULL：

1. int base64_decode(char *str,int str_len,char *decode,int decode_buffer_len){
   
2.     int len=0;
   
3.     BIO *b64,*bmem;
   
4.     b64=BIO_new(BIO_f_base64());
   
5.     bmem=BIO_new_mem_buf(str,str_len);
   
6.     bmem=BIO_push(b64,bmem);
   
7.     len=BIO_read(bmem,decode,str_len);
   
8.     decode[len]=0;
   
9.     BIO_free_all(bmem);
   
10.     return 0;
    
11. }
    
12. 
    
13. result is NULL, nothing decoded.

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folklore

自已写一个， 10分钟。。。

rover12421

Encryption/Decryption

How do I base64-encode something?

Use the enc -base64 option.

# send encoded contents of file.txt to stdout
openssl enc -base64 -in file.txt

# same, but write contents to file.txt.enc
openssl enc -base64 -in file.txt -out file.txt.enc
It’s also possible to do a quick command-line encoding of a string value:

$ echo "encode me" | openssl enc -base64
ZW5jb2RlIG1lCg==

Note that echo will silently attach a newline character to your string. Consider using its -n option if you want to avoid that situation, which could be important if you’re trying to encode a password or authentication string.

$ echo -n "encode me" | openssl enc -base64
ZW5jb2RlIG1l

rover12421

echo 默认会在后面加上"\n",使用-n参数则不会
Cg== 是"\n"的base64

sugelawa

回复 4# rover12421 在命令行中使用echo会被添加\n，那为何php中base64_encode编码的，我在C代码中解码无法得出结果呢？


   

rover12421

回复 5# sugelawa


    测试发现openssl解码的一个特点,用文件测试的,比echo明显点
    openssl enc -base64 -d -in a.txt
    如果文件里只有base64编码,末尾没有'\n',openssl无法解码,测试文件内容分下面三种

1. YWFh
   
2. YWFhYWFh
   
3. YWFhCg==
   
4. YWFhYWFhCg==

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如果在内容后面加个回车'\n'

1. YWFh\n
   
2. YWFhYWFh\n
   
3. YWFhCg==\n
   
4. YWFhYWFhCg==\n

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YWFhCg==\n  能的到正确结果 aaa
YWFhYWFhCg==\n  能的到正确结果 aaaaaa

YWFh\n 和 YWFhYWFh\n 能的到结果,但是末尾多了个字符.终端显示是%

    至于你的c代码,表示看不懂....

sugelawa

回复 6# rover12421 真不知道openssl怎么会这么干，粗暴地改变目标字串内容。C代码部分是使用openssl的API实现的，网上找的，后来在别人指点下这样解决了：

1. Add BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL) after the BIO_new() call to tell OpenSSL that all the input appears in a single line without newline.

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