Netscape Communicator 4, RSA 1024 and SHA-1 in Brexit Trade Agreement

As Prof Bill Buchanan OBE on LinkedIn points out, the Brexit Trade Agreement [1] on Page 921 goes:

The underlying certificate used by the s/MIME mechanism has to be in compliance with X.509 standard. In order to ensure common standards and procedures with other Prüm applications, the processing rules for s/MIME encryption operations or to be applied under various Commercial Product of the Shelves (COTS) environments, are as follows:

– the sequence of the operations is: first encryption and then signing,

– the encryption algorithm AES (Advanced Encryption Standard) with 256 bit key length and RSA with 1024 bit key length shall be applied for symmetric and asymmetric encryption respectively,

– the hash algorithm SHA-1 shall be applied.

s/MIME functionality is built into the vast majority of modern e-mail software packages including Outlook, Mozilla Mail as well as Netscape Communicator 4.x and inter-operates among all major email software packages.

[1]https://assets.publishing.service.gov.uk/government/uploads/...