How to Decode Bytes into Integers for Encryption/Decryption?

Decoding Bytes into Integers for Encryption/Decryption

When working with encryption and decryption algorithms, it is essential to convert bytes into integers and vice versa. The question at hand pertains to converting bytes to integers. While the bytes() function can convert an integer to a byte object, the inverse process requires a different approach.

Enter Python's built-in method int.from_bytes(). This function takes three arguments: bytes to convert, byte order, and optionally, a signed flag.

Byte Order

Byte order determines the endianness of the integer representation:

• big: Most significant byte is at the start of the byte array.
• little: Most significant byte is at the end of the byte array.

Signed Integer

The signed flag specifies whether two's complement is used to represent negative integers.

Examples

Demonstrating int.from_bytes():

<code class="python">int.from_bytes(b'\x00\x01', "big")                         # 1
int.from_bytes(b'\x00\x01', "little")                      # 256

int.from_bytes(b'\x00\x10', byteorder='little')            # 4096
int.from_bytes(b'\xfc\x00', byteorder='big', signed=True)  #-1024</code>

Additional Notes

• bytes are immutable byte sequences in Python, representing binary data.
• Integers are immutable numeric values in Python.
• Understanding byte order is crucial for data interpretation, especially when working across different platforms.
• int.from_bytes() provides a convenient and efficient way to convert bytes to integers while accommodating endianness and signed integer representation.

The above is the detailed content of How to Decode Bytes into Integers for Encryption/Decryption?. For more information, please follow other related articles on the PHP Chinese website!