> For the complete documentation index, see [llms.txt](https://cryptobook.mupceet.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://cryptobook.mupceet.com/cryptographic-hash-functions/hash-functions-examples.md).

# 哈希函数——示例

In this section we shall provide a few **examples** about calculating cryptographic hash functions in Python.

在本节中，我们将提供一些有关在 Python 中使用加密哈希函数计算的**示例**。

## 在 Python 中使用加密哈希函数计算

We shall use the standard Python library `hashlib`. The input data for hashing should be given as **bytes sequence** (bytes object), so we need to **encode the input string** using some text encoding, e.g. `utf8`. The produced **output data** is also a bytes sequence, which can be printed as hex digits using `binascii.hexlify()` as shown below:

我们将使用标准的 Python 库 `hashlib`。用于哈希的输入数据应该以**字节序列**（bytes 对象）的形式给出，因此我们需要使用一些文本编码例如 `utf8` **对输入字符串进行编码**。产生的**输出数据**也是一个字节序列，可以使用 `binascii.hexlify()` 打印为十六进制数字，如下所示:

```python
import hashlib, binascii

text = 'hello'
data = text.encode("utf8")

sha256hash = hashlib.sha256(data).digest()
print("SHA-256:   ", binascii.hexlify(sha256hash))

sha3_256 = hashlib.sha3_256(data).digest()
print("SHA3-256:  ", binascii.hexlify(sha3_256))

blake2s = hashlib.new('blake2s', data).digest()
print("BLAKE2s:   ", binascii.hexlify(blake2s))

ripemd160 = hashlib.new('ripemd160', data).digest()
print("RIPEMD-160:", binascii.hexlify(ripemd160))
```

Run the above code example: <https://repl.it/@nakov/Hashes-SHA2-SHA3-BLAKE2-RIPEMD-in-Python>.

可在此链接中运行该示例代码：<https://repl.it/@nakov/Hashes-SHA2-SHA3-BLAKE2-RIPEMD-in-Python>。

The expected **output** from the above example looks like this:

上述示例的预期**输出**如下：

```
SHA-256:    b'2cf24dba5fb0a30e26e83b2ac5b9e29e1b161e5c1fa7425e73043362938b9824'
SHA3-256:   b'3338be694f50c5f338814986cdf0686453a888b84f424d792af4b9202398f392'
BLAKE2s:    b'19213bacc58dee6dbde3ceb9a47cbb330b3d86f8cca8997eb00be456f140ca25'
RIPEMD-160: b'108f07b8382412612c048d07d13f814118445acd'
```

Calculating `Keccak-256` hashes (the hash function used in the Ethereum blockchain) requires non-standard Python functions. In the below example we use the `pycryptodome` package available from PyPI: <https://pypi.org/project/pycryptodome>.

计算 `Keccak-256` 哈希（以太坊区块链中使用的哈希函数）需要非标准的 Python 函数。在以下示例中，我们使用可从 PyPI 获得的 `pycryptodome` 软件包：<https://pypi.org/project/pycryptodome>。

First install "pycryptodome" (<https://www.pycryptodome.org>)

首先安装 `pycryptodome` 软件包（<https://www.pycryptodome.org>）。

```python
pip install pycryptodome
```

Now write some Python code to calculate a **Keccak-256** hash:

现在编写一些 Python 代码来计算一个 **Keccak-256** 的哈希值：

```
from Crypto.Hash import keccak
import binascii

keccak256 = keccak.new(data=b'hello', digest_bits=256).digest()
print("Keccak256:", binascii.hexlify(keccak256))
```

Run the above code example: <https://repl.it/@nakov/Keccak256-in-Python>.

可在此链接中运行该示例代码：<https://repl.it/@nakov/Keccak256-in-Python>。

The **output** from the above examples is:

上述示例的预期**输出**为：

```
Keccak256: b'1c8aff950685c2ed4bc3174f3472287b56d9517b9c948127319a09a7a36deac8'
```