mbedtls/docs/3.0-migration-guide.d/rsa-padding.md

Remove the padding parameters from mbedtls_rsa_init()

This affects all users who use the RSA encryption, decryption, sign and verify APIs.

The function mbedtls_rsa_init() no longer supports selecting the PKCS#1 v2.1 encoding and its hash. It just selects the PKCS#1 v1.5 encoding by default. If you were using the PKCS#1 v2.1 encoding you now need, subsequently to the call to mbedtls_rsa_init(), to call mbedtls_rsa_set_padding() to set it.

To choose the padding type when initializing a context, instead of

    mbedtls_rsa_init(ctx, padding, hash_id);

, use

    mbedtls_rsa_init(ctx);
    mbedtls_rsa_set_padding(ctx, padding, hash_id);

To use PKCS#1 v1.5 padding, instead of

    mbedtls_rsa_init(ctx, MBEDTLS_RSA_PKCS_V15, <ignored>);

, just use

    mbedtls_rsa_init(ctx);