Go language document analysis: crypto/sha1.Sum function implements SHA1 hash calculation

Go language document analysis: crypto/sha1.Sum function implements SHA1 hash calculation, specific code examples are required

Abstract: This article analyzes the Go language crypto/sha1 package The analysis of the Sum function in this article introduces the implementation principle of SHA1 hash calculation in detail, and gives specific code examples.

Keywords: Go language, crypto/sha1, Sum function, SHA1 hash calculation

1. Introduction

In the field of computer science, hash algorithms are widely used in the field of data security. SHA1 (Secure Hash Algorithm 1) is a common hash algorithm used to generate a unique digest of data. The Go language provides the crypto/sha1 package to implement SHA1 hash calculations, of which the Sum function is one of its core functions.

This article will introduce the implementation principle of SHA1 hash calculation in detail through the analysis of the crypto/sha1.Sum function, and give specific code examples.

2. Implementation principle of SHA1 hash calculation

The SHA1 hash algorithm mainly consists of the following four steps:

1. Data filling: First, the hash will be calculated The data of the hash value is filled so that its length meets certain conditions. The specific operation is to add a "1" at the end of the data, and then fill in a series of "0" until the condition is met.
2. Data grouping: Group the filled data into groups. The length of each group is 512 bits (64 bytes).
3. Expansion operation: Expand operation is performed on each group to obtain an 80-word message expansion.
4. Hash calculation: Through loop iteration, message expansion and hash value update operations are performed on each group, and the SHA1 hash value is finally obtained.

3. The crypto/sha1 package in Go language

The crypto/sha1 package in Go language provides the function of implementing SHA1 hash calculation. Among them, the Sum function is the core calculation function, and its function signature is as follows:

func Sum(data []byte) [Size]byte

The function accepts a byte slice as a parameter and returns a An array of length Size(20) representing the calculated SHA1 hash value.

Specifically, the implementation process of the Sum function is as follows:

1. Determine whether the length of the input data is 0. If so, directly return a hash value of all 0.
2. Create a variable of type sha1 and initialize it through the sha1.New function.
3. Use the Write method of the sha1 type to write the input data to the sha1 variable.
4. Finally, the final SHA1 hash value is obtained through the Sum method of the sha1 type.

4. Specific code example

Next, we give a specific code example to demonstrate how to use the Sum function in the crypto/sha1 package to calculate the SHA1 hash value.

package main

import (
    "crypto/sha1"
    "fmt"
)

func main() {
    data := []byte("Hello, World!")
    hash := sha1.Sum(data)
    fmt.Printf("SHA1 Hash: %x
", hash)
}

Run the above code, you can get the following output:

SHA1 Hash: 2ef7bde608ce5404e97d5f042f95f89f1c232871

In this example, we convert the string "Hello, World!" into words Section slices and calculates its SHA1 hash value through the Sum function. Finally, the output is formatted and printed to the console.

5. Summary

This article introduces the implementation principle of SHA1 hash calculation in detail by analyzing the Sum function in the Go language crypto/sha1 package, and gives specific code examples. . The SHA1 hash function is an algorithm widely used in the field of computer security. It is very important to be familiar with its implementation principles and usage methods to ensure data security. I hope this article will be helpful to readers in their understanding and application of SHA1 hash calculation.

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