How to disable the ciphertext stealing of crypto library?

[YChen.51]

Hi all

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My cipher text from STM32F429 crypto library(AES-CBC-256) is CTS(Ciphertext Stealing)，but the cipher text can'e decrypt by openssl on my PC because the file length is not correct.

What can I do to solve it?

Thanx

[Bubbles]

Hi @YChen.5​ ,

the usual way to round up the length of a plaintext to a size that is conformant with the cryptographic standard is to use a technique called padding. Look up what padding is recommended in your case. You may probably use zeroes to extend the content to required length.

J