(
Public 
Key 
Cryptography 
Standards)  Following is a brief summary of RSA Laboratory standards for public key cryptography.  See 
public key cryptography, 
digital signature, 
x.509 and 
code signing.
 RSA STANDARDS
 Format        Purpose
 PKCS#1   Encryption and signing
 PKCS#3   Diffie-Hellman key protocol
 PKCS#5   String encryption
 PKCS#7   Signed cert
 PKCS#8   Private key and attributes
 PKCS#9   Attributes
 PKCS#10  Cert signing request (CSR)
 PKCS#11  Cryptoki smart card API
 PKCS#12  Cert and publisher private key
 PKCS#15  Cryptoki token credentials
 PKCS#12  X.509 Cert and private keys
 PKCS#13  Elliptic Curve cryptography
 PKCS#14  Pseudo-random number generation
 Code Signing Sequence
 PKCS#10  Cert signing request (CSR)
 PKCS#7   Signed cert
 PKCS#12  Cert and private key 
          (PFX or P12 extension)
 Cert = X.509 certificate
The Code Signing Process
The combination of the signed digital certificate and the signed executable file ensures that the executable has come from a valid publisher and has not been tampered with.  See 
code signing.