This step is applicable to PEM message types ENCRYPTED, MIC-ONLY, and MIC-CLEAR. The message text is converted to a universal canonical form, similar to the inter-SMTP representation  as defined in RFC 821  and RFC 822 . The procedures performed in order to accomplish this conversion are dependent on the characteristics of the local form and so are not specified in this RFC.
PEM canonicalization assures that the message text is represented with the ASCII character set and "<CR><LF>" line delimiters, but does not perform the dot-stuffing transformation discussed in RFC 821, Section 4.5.2. Since a message is converted to a standard character set and representation before encryption, a transferred PEM message can be decrypted and its MIC can be validated at any type of destination host computer. Decryption and MIC validation is performed before any conversions which may be necessary to transform the message into a destination-specific local form.