"ID",Critical,Packet Type Description,Shorthand,Reference
0,Yes,Reserved - this Packet Type ID MUST NOT be used,,[RFC9580]
1,Yes,Public Key Encrypted Session Key Packet,PKESK,"[RFC9580, Section 5.1]"
2,Yes,Signature Packet,SIG,"[RFC9580, Section 5.2]"
3,Yes,Symmetric Key Encrypted Session Key Packet,SKESK,"[RFC9580, Section 5.3]"
4,Yes,One-Pass Signature Packet,OPS,"[RFC9580, Section 5.4]"
5,Yes,Secret Key Packet,SECKEY,"[RFC9580, Section 5.5.1.3]"
6,Yes,Public Key Packet,PUBKEY,"[RFC9580, Section 5.5.1.1]"
7,Yes,Secret Subkey Packet,SECSUBKEY,"[RFC9580, Section 5.5.1.4]"
8,Yes,Compressed Data Packet,COMP,"[RFC9580, Section 5.6]"
9,Yes,Symmetrically Encrypted Data Packet,SED,"[RFC9580, Section 5.7]"
10,Yes,Marker Packet,MARKER,"[RFC9580, Section 5.8]"
11,Yes,Literal Data Packet,LIT,"[RFC9580, Section 5.9]"
12,Yes,Trust Packet,TRUST,"[RFC9580, Section 5.10]"
13,Yes,User ID Packet,UID,"[RFC9580, Section 5.11]"
14,Yes,Public Subkey Packet,PUBSUBKEY,"[RFC9580, Section 5.5.1.2]"
15-16,,Unassigned,,
17,Yes,User Attribute Packet,UAT,"[RFC9580, Section 5.12]"
18,Yes,Symmetrically Encrypted and Integrity Protected Data Packet,SEIPD,"[RFC9580, Section 5.13]"
19,Yes,Reserved (formerly Modification Detection Code Packet),,"[RFC9580, Section 5.13.1]"
20,Yes,Reserved,,[RFC9580]
21,Yes,Padding Packet,PADDING,"[RFC9580, Section 5.14]"
22-39,Yes,Unassigned Critical Packets,,
40-59,No,Unassigned Non-Critical Packets,,
60-63,No,Private or Experimental Use,,[RFC9580]