From Alan Cox
Mike Orton need not worry so much about the Royal Mail’s public key encryption system
(Letters, 10 April, p 55). A peek at its website
(http://www.royalmail.co.uk/atwork/viacode/news/tech_brief. htm) shows that the
public keys are 1024 bits long rather than 128. 128-bit keys are used with a
symmetric cypher rather than the asymmetric RSA. The site informs us: “The
software is independent of encryption algorithms, but comes as standard with a
choice of symmetric and asymmetric cyphers including IDEA-128 and RSA1024″.
There may be other reasons to worry about cryptography but RSA with 128-bit
keys from Royal Mail isn’t one of them.
Heath, Cardiff
