5. Descriptive Grammar

   ; Addendum to PEM BNF representation, using RFC 822 notation
   ; Provides specification for official PEM cryptographic algorithms,
   ; modes, identifiers and formats.

   ; Imports <hexchar> and <encbin> from RFC [1421]

       <dekalgid> ::= "DES-CBC"
       <ikalgid>  ::= "DES-EDE" / "DES-ECB" / "RSA"
       <sigalgid> ::= "RSA"
       <micalgid> ::= "RSA-MD2" / "RSA-MD5"

       <dekparameters> ::= <DESCBCparameters>
       <DESCBCparameters> ::= <IV>
       <IV> ::= <hexchar16>

       <symencdek> ::= <DESECBencDESCBC> / <DESEDEencDESCBC>
       <DESECBencDESCBC> ::= <hexchar16>
       <DESEDEencDESCBC> ::= <hexchar16>

       <symencmic> ::= <DESECBencRSAMD2> / <DESECBencRSAMD5>
       <DESECBencRSAMD2> ::= 2*2<hexchar16>
       <DESECBencRSAMD5> ::= 2*2<hexchar16>

       <asymsignmic> ::= <RSAsignmic>
       <RSAsignmic> ::= <encbin>

       <asymencdek> ::= <RSAencdek>
       <RSAencdek> ::= <encbin>

       <hexchar16> ::= 16*16<hexchar>