[openssl-dev] OpenSSL and certain PEM formats

[Sean Leonard]

On 12/17/2014 11:04 AM, Salz, Rich wrote:
> Probably also worth documenting the legacy "RSA PRIVATE KEY" defined by openssl and used mainly in legacy pre-pkcs8 support

There is a paragraph on "algorithm agility"; the legacy labels (like RSA 
PRIVATE KEY) are not mentioned because for interchange, PKCS #8 is 
perfectly reasonable and is algorithm-agile.

IIRC, there are some implementations out there (by that I mean certain 
well-known certification authorities that I will not name) that 
specifically look for "RSA PRIVATE KEY", and measure key strength by 
looking at the length of the blob. This method prevents other algorithms 
(e.g., ECC) from being used, and when other algorithms (e.g., ECC) are 
used, the key gets rejected for no other reason than because the key 
appears to be too "small" and therefore weak.

Sean