PHP Secure Communications Library – phpseclib
PHP Secure Communications Library is a set of pure PHP implementations for data encryption and cryptographic algorithms DES, 3DES, RC4, Rijndael, AES, RSA (PKCS#1 compliant [v2.1]), SSH-1, SSH-2, and SFTP.
Some of the internal functions of All-in-One WP Migration are dependent on the phpseclib module.
If you see this message, your server does not have the phpseclib extension installed. To use All-in-One WP Migration, please contact your hosting provider and request to install phpseclib. Otherwise, consider using a different hosting provider.