Encrypt & decrypt Gravity Forms velden

decrypt-2.php

<?php

# Like on: https://docs.gravityforms.com/gform_get_input_value/

add_filter( 'gform_get_input_value', 'gf_custom_decode_field', 10, 4 );
function gf_custom_decrypt_field( $value, $entry, $field, $input_id )
{
    return GFCommon::decrypt( $value );
}
// end gf_custom_decrypt_field

decrypt.php

<?php

# Like on: https://docs.gravityforms.com/gform_get_input_value/

add_filter( 'gform_get_input_value', 'gf_custom_decode_field', 10, 4 );
function gf_custom_decrypt_field( $value, $entry, $field, $input_id )
{
    # Add a check to see if a field has to be decrypted, 
    # because it's possible you're adding this after already having entries
    
    $date_implemented = '2018-03-18 09:00:00'; # format: yyyy-mm-dd hh:mi:ss
    $date_entry = rgar( $entry, 'date_created' );
    
    # Entry is from after implementing encrypting entries
    if ( strtotime( $date_entry ) >= $date_implemented )
        return GFCommon::decrypt( $value );
    
    # Entry is from before implementing encrypting entries
    return $value;
}
// end gf_custom_decrypt_field

encrypt.php

<?php

# Like on: https://docs.gravityforms.com/gform_save_field_value/

add_filter( 'gform_save_field_value', 'gf_custom_save_field_value', 10, 4 );
function gf_custom_save_field_value( $value, $lead, $field, $form )
{
    return GFCommon::encrypt( $value );
}
// end gf_custom_save_field_value

Updated version: https://gist.github.com/hiranthi/ffcbae234edda3e08c6db13884c24450