1.2 Hashlib Module API Documentation#
1. Overview#
The uhashlib library provides binary data hashing functionality based on MD5, SHA1, and SHA2 algorithms.
2. API Introduction#
The uhashlib library provides three classes: md5, sha1, and sha256. These classes each implement two functions: the data update function update() and the message digest function digest(). Among them, md5 and sha1 are software implementations in MicroPython; sha256 is accelerated by the underlying hardware accelerator.
Note: This document does not detail the usage steps for md5 and sha1. For specifics, please refer to the MicroPython hash official documentation
2.1 Class sha256#
Description
The sha256 class is used to create a SHA256 hash object and optionally send data to it.
Syntax
uhashlib.sha256([data])
Parameters
Parameter Name |
Description |
Input/Output |
|---|---|---|
data (optional) |
Binary data |
Input |
Return Value
Return Value |
Description |
|---|---|
0 |
Success |
Non-0 |
Failure |
Example
data = bytes([0]*64)
hash_obj = uhashlib.sha256(data)
hash_obj.update(data)
dgst = hash_obj.digest()
print(dgst)
2.1.1 Data Update Function update()#
Description
If you need to input binary data multiple times, you can call the update() function to update the data.
Syntax
obj.update(data)
Parameters
Parameter Name |
Description |
Input/Output |
|---|---|---|
data |
Input binary data |
Input |
Return Value
Return Value |
Description |
|---|---|
0 |
Success |
Non-0 |
Failure |
2.1.2 Message Digest Function digest()#
Description Returns the hash value of all input data.
Note: In MicroPython, using this function completes the final calculation, not just displaying the result. Therefore, it can only be called once. If you need to use the value multiple times, please save it to a variable.
Syntax
dgst = hash.digest()
print(dgst)
/*********** Note ***********/
a = hash.digest()
b = hash.digest() # Error
Parameters
None
Return Value
Return Value |
Description |
|---|---|
0 |
Success |
Non-0 |
Failure |
2.1.3 Hexadecimal Message Digest Function hexdigest()#
This method is not implemented. You can use binascii.hexlify(hash.digest()) to achieve a similar effect.
3. Example Program#
Calculate Hash Value#
import uhashlib
import binascii
# Initialize sha256 object
obj = uhashlib.sha256()
# Input data1
obj.update(b'hello')
# Input data2
obj.update(b'world')
# Compute digest
dgst = obj.digest()
print(binascii.hexlify(dgst))
# b'936a185caaa266bb9cbe981e9e05cb78cd732b0b3280eb944412bb6f8f8f07af'