Internet Draft Jim Schaad November 19, 2000 Expires in six months Certificate Distribution Specification draft-ietf-smime-certdist-05.txt Status of this memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet-Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. To learn the current status of any Internet-Draft, please check the "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow Directories on ftp.is.co.za (Africa), nic.nordu.net (Europe), munnari.oz.au (Pacific Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). Abstract Current methods of publishing certificates in directory services are restricted to just certificates. This document provides a method of publishing certificates with secondary support information such as the SMimeCapabilities attribute (containing bulk algorithm support) in a way that is both authenticated and bound to a given certificate. This draft is being discussed on the "ietf-smime" mailing list. To join the list, send a message to with the single word "subscribe" in the body of the message. Also, there is a Web site for the mailing list at . 1. Introduction This document discusses a new method of publishing certificates in a directory to provide authenticated attributes as part of the certificate publishing process. This allows for the addition of information such as the SMimeCapabilities attribute from [SMIME] which contains information about the bulk encryption algorithms supported by the End-Entity's cryptography module. Section 2 discusses the current set of publishing methods available for use, along with the benefits and restrictions of each method. Schaad 1 CertDist May 2000 Section 3 covers the definition and properties of a SMimeCertificatePublish object. The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT","SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in RFC 2119. 2. Current Publishing Methods There are several different ways to publish certificate information. These methods include the userCertificate property in LDAP directories, sending signed objects between users, and transport of certificate files (either bare or as CMS degenerate signed objects). Each of these methods has benefits and drawbacks. Each of these methods will now be briefly discussed. Public Directory A public directory may be used to distribute certificates. LDAP currently has the userCertificate property defined just for that purpose. The benefits of using a public directory are that a sender may create an encrypted object for a recipient without first receiving information (such as a signed message) from the recipient. However the use of directories has two drawbacks: First, the set of bulk algorithms supported by the recipient is unknown. Second, the chain of certificates needed to validate the userĘs certificate needs to be found in another manner. Although there exists a property for listing bulk algorithms in the X.509 directory, it has no way of binding a list of algorithms to a single certificate. It is possible that a certificate bound to a key located on a hardware device is limited to a small set of algorithms, while a certificate bound to a software implementation can have a greater set of algorithms associated with it. The problem of determining what to publish is made all the harder because it is possible the intersection of the algorithms is empty. We therefore need to have a method that binds a specific list of algorithms to a specific certificate. Building the necessary chain of certificates is the other problem. While it is possible to do direct lookup using an X.500 directory, the same is not true of an LDAP directory especially if one is using cross-certificates to a different root. While the problem is made somewhat easier by the Authority Information Access extension (it is possible to know where to look for the issuer certificate), it still requires multiple network accesses to build the certificate chain for what is relatively static information. If we can include at least one common chain with the userĘs certificate this problem is simplified. Certificate Files Schaad 2 CertDist May 2000 Using certificate files for certificate distribution has the benefit of already being in wide spread use. (They are commonly used for certificate distribution from Certificate Authorities either as part of the enrollment protocol or from web based repositories.) The degenerate CMS signed object form, certificate files may carry a set of certificates to allow a sender to validate the recipients certificates. However, they suffer from two drawbacks. First, as with the public directory, the additional information is not available as part of the certificate file. Second, the certificate is obtained from either the recipient one is encrypting for or a third party (not a directory). Signed Objects Using signed objects for certificate distribution has the benefit of allowing additional information such as the SMimeCapabilities attribute to be carried as part of the package. It also allows for the inclusion of additional certificates to be used in verifying the encryption certificate used to build an encrypted object. However, it has the drawback that the initialization process is done via a one-on-one process. 3. SMimeEncryptCerts When publishing one's own encryption certificates, it is often advisable to publish a wide selection of certificates to insure maximum interoperability. This section describes an attribute that is used both to identify the set of encryption certificates and to establish the set of bulk encryption algorithms supported by each of the certificates. The SMimeEncryptCerts attribute is used to identify one's own encryption certificates to the other party. This attribute is a sequence so that more than one encryption certificate can be identified in a single SignerInfo object. Each certificate is then given a set of capabilities so senders can identify the correct certificate to use for specific capabilities. The structure and OID for the SMimeEncryptCerts attribute are: id-aa-smimeEncryptCerts OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-aa(2) 13 } SMimeEncryptCert ::= SEQUENCE { hash Hash, capabilities SMIMECapabilities } SMimeEncryptCerts ::= SEQUENCE OF SmimeEncryptCert Hash ::= OCTET STRING - SHA1 hash of the certificate When a certificate appears in an SMimeEncryptCerts attribute, the certificate MUST be available to the verifier in a well known Schaad 3 CertDist May 2000 location. For SignedData objects, this is the certificate bag in the object. The order of certificates in the SMimeEncryptCerts attribute is the preferred order of use by the sender. If present, the SMimeEncryptCerts attribute MUST be an authenticated attribute; it MUST NOT be an unauthenticated attribute. CMS defines authenticatedAttributes as a SET OF AuthAttribute. A SignerInfo MUST NOT include multiple instances of the SMimeEncryptCerts attribute. CMS defines the ASN.1 syntax for the authenticated attributes to include attrValues SET OF AttributeValue. A SMimeEncryptCerts attribute MUST only include a single instance of AttributeValue. There MUST be one instance of AttributeValue present in the attrValues SET OF AttributeValue. 4. SMimeCertificatePublish Object The structure of the SMimeCertificatePublish object is defined in this section. This object has the benefit that it is published into a directory service (and thus is available to all parties) and it contains a signed object that allows it to carry the additional information desired to increase interoperability. This section describes the LDAP directory schema, the body content and additional restrictions on the attribute and signers of the SignedData object used in publishing the user's certificate. The ASN definition of a SMimeCertificatePublish object is the same a CMS signed object. SMimeCertificatePublish ::= ContentInfo Where the contentType is id-signed-data and the content is a SignedData content. A SMimeCertificatePublish object MAY contain multiple SignerInfo objects. Each SignerInfo object is independent. This document imposes no restrictions on attributes that appear in more that one SignerInfo object. 4.1 Signed Content The SMimeCertificatePublish object is explicitly designed to carry no body content. All information is carried in the signed attribute section of the SignerInfo. The following object identifier is used to distinguish the content of a SMimeCertificatePublish: id-ct-publishCert OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs9(9) smime(16) id-ct(1) 3) When creating a SMimeCertificatePublish object, the eContent of the Signed-Data object is omitted and the eContentType OID is set to id- Schaad 4 CertDist May 2000 ct-publishCert. Note this is different from an empty content, which would be represented as an octet string containing zero bytes. The hash of the body (used in the id-message-digest attribute) is set to the initialization value of the hash function. (This is expected to provide the same result as if you had hashed a body containing exactly 0 bytes.) 4.2 Signed Attributes The signed attributes section MUST be present in the SignerInfo object, and the following signed attributes MUST be present: The signing-time attribute (from [CMS]), the SMimeCapabilities and SMIMEEncryptionKeyPreference (from [SMIME]). 4.3 CertificateSet This draft imposes additional restrictions on the set of certificates to be included in the SignedData object beyond those specified in [CMS] and [SMIMECERT]. A chain of certificate from the end-entity certificate(s) to the root certificate(s) MUST be included in the CertificateSet. Unlike in S/MIME messages the root certificate MUST be included in the CertificateSet. The root certificate is included so that end-entities have a better chance of finding and independently verifying the trustworthiness of the root certificate based on its content. User agents MUST NOT automatically trust any root certificate found in a SMimeCertificatePublish object. 4.4 Signing Certificate The SMimeCertificatePublish object MUST be signed by a signing certificate associated with the end-entity, or a signing certificate of a CA in the validation path of the encryption certificate. Part of the process of extracting certificates involves comparing the certificate found to the address matching the directory look-up. The validation SHOULD match the address used to look up the certificate with one of the names found in the certificate. Thus, if an RFC822 name was used to do the directory look-up, the RFC822 name would be in the SubjectAltName extension on the certificate. The steps for extracting the encryption certificate from a SMimeCertificatePublish object are as follows: 1. Verify that the SMimeCertificatePublish object contains a valid signature and the certificate used to sign the message can be validated. 2. Does the certificate used to sign the SMimeCertificatePublish object "match" the intended recipient of the encryption object? If so, proceed to step 3 else no encryption certificate is found. Schaad 5 CertDist May 2000 3. Get the set of potential encryption certificates from the SMIMEEncryptCerts attribute in the signed attributes of the SMimeCertificatePublish object. 4. Select the encryption certificate from the set of potential encryption certificates by validating the certificate and examining the set of encryption algorithms. In all cases, once an encryption certificate has been obtained, the standard methods of validating signatures on the certificate and checking for revocation MUST be followed. 4.5 LDAP Schema After a SignedData object has been produced, it needs to be published into one or more directories. The following auxiliary object class MAY be used to represent certificate subjects: pkiUser OBJECT-CLASS ::= { SUBCLASS OF { top} KIND auxiliary MAY CONTAIN {userSMimeCertificate} ID joint-iso-ccitt(2) ds(5) objectClass(6) pkiUser(21)} userSMimeCertificate ATTRIBUTE ::= { WITH SYNTAX ContentInfo EQUALITY MATCHING RULE contentInfoExactMatch ID 1 2 840 113549 1 9 16 4 1 } If the CA is the only entity that can write to the directory, it may wish to provide some mechanism for updating the attributes such as the smimeUserCapabilities in the published object. 4.6 MIME Encoding The application/pkcs7-mime-publish content type is used to carry SMimeCertificatePublish objects as mime objects. The optional "name" parameter SHOULD be emitted as part of the Content-Type field. The file extension for the file name SHOULD be ".p7p". A. ASN Module SMimeCertDistributionSyntax { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) } DEFINITIONS IMPLICIT TAGS ::= BEGIN -- EXPORTS All -- The types and values defined in this module are exported for -- use in the other ASN.1 modules. Other applications may use -- them for their own purposes. Schaad 6 CertDist May 2000 IMPORTS -- SMime Cryptographic Message Format ContentInfo FROM CryptographicMessageSyntax { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) cms(1) } -- SecureMimeMessageV3 SMIMECapabilities FROM SecureMimeMessageV3 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) modules(0) smime(4)}; -- S/MIME Object Identifier Registry id-smime OBJECT IDENTIFIER ::= { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) pkcs-9(9) smime(16) } -- Authenticated Attribute identifying Encryption Certificates -- Value is a single SMimeEncryptCerts id-aa-smimeEncryptCerts OBJECT IDENTIFIER ::= { id-smime id-aa(2) 13 } SMimeEncryptCerts ::= SEQUENCE OF SMimeEncryptCert SMimeEncryptCert ::= SEQUENCE { hash Hash, capabilities SMIMECapabilities } Hash ::= OCTET STRING -- SHA1 hash of the certificate -- Content Type of Certificate publish message. -- Signed content is detached and empty id-ct-publishCert OBJECT IDENTIFIER ::= { id-smime id-ct(1) 3 } SMimeCertificatePublish ::= ContentInfo END -- of SMimeCertDistributionSyntax B. Backwards Compatibility The SMimeCertificatePublish object is based on work previously done at both Microsoft and Netscape. Both of these companies have implemented a version of userSMimeCertificate in their mail LDAP directory structures. Microsoft has also put the property into its MAPI based directory schema. Both companies use a ContentInfo object containing a SignedData object with one SignerInfo object. In both cases however the eContent is tagged with id-data not id-ct-publishCert. The actual content is omitted from the SMimeCertificatePublish object. Schaad 7 CertDist May 2000 Microsoft has also produced an early version of the SMimeEncryptCerts attribute. The syntax for this structure is id-Microsoft-SMimeEncryptCert OBJECT IDENTIFIER ::= {1 3 6 1 4 1 311 16 4} Microsoft-SMimeEncryptionCert ::= IssuerAndSerialNumber A description of IssuerAndSerialNumber can be found in [CMS]. C. Registration of MIME To: ietf-types@iana.org Subject: Registration of MIME media type application/pkcs7-mime- publish MIME media type name: application MIME subtype name: pkcs7-mime-publish Required parameters: none Optional parameters: name, filename Encoding considerations: Will be binary data, therefore should use base-64 encoding Security considerations: There is no requirement for additional security mechanisms to be applied at this level. The required mechanisms are designed into the SMimeCertificatePublish content. Interoperability considerations: - Published specification: this document Applications that use this media type: Secure Internet mail and other secure data transports. Additional information: File extension (s): p7p Macintosh File Type Code (s): - Person and email address to contact for further information: Jim Schaad, jimsch@exmsft.com Intended usage: COMMON D. Example Message In this example Alice makes the statement that messages encrypted for her should use one of two encryption certificates issued to Bob. 0 30 NDEF: SEQUENCE { 2 06 9: OBJECT IDENTIFIER signedData (1 2 840 113549 1 7 2) Schaad 8 CertDist May 2000 13 A0 NDEF: [0] { 15 30 NDEF: SEQUENCE { 17 02 1: INTEGER 1 20 31 11: SET { 22 30 9: SEQUENCE { 24 06 5: OBJECT IDENTIFIER sha1 (1 3 14 3 2 26) 31 05 0: NULL : } : } 33 30 NDEF: SEQUENCE { 35 06 11: OBJECT IDENTIFIER : id-ct-publishCert (1 2 840 113549 1 9 16 1 3) 48 A0 NDEF: [0] { : } : } 54 A0 3298: [0] { 58 30 491: SEQUENCE { 62 30 340: SEQUENCE { 66 A0 3: [0] { 68 02 1: INTEGER 2 : } 71 02 16: INTEGER : 46 34 6B C7 80 00 56 BC 11 D3 6E 2E 9F F2 50 20 89 30 13: SEQUENCE { 91 06 9: OBJECT IDENTIFIER : sha1withRSAEncryption (1 2 840 113549 1 1 5) 102 05 0: NULL : } 104 30 18: SEQUENCE { 106 31 16: SET { 108 30 14: SEQUENCE { 110 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 115 13 7: PrintableString 'CarlRSA' : } : } : } 124 30 30: SEQUENCE { 126 17 13: UTCTime '990818070000Z' 141 17 13: UTCTime '391231235959Z' : } 156 30 18: SEQUENCE { 158 31 16: SET { 160 30 14: SEQUENCE { 162 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 167 13 7: PrintableString 'CarlRSA' : } : } : } 176 30 159: SEQUENCE { 179 30 13: SEQUENCE { 181 06 9: OBJECT IDENTIFIER : rsaEncryption (1 2 840 113549 1 1 1) 192 05 0: NULL : } 194 03 141: BIT STRING 0 unused bits Schaad 9 CertDist May 2000 : 30 81 89 02 81 81 00 E4 4B FF 18 B8 24 57 F4 77 : FF 6E 73 7B 93 71 5C BC 33 1A 92 92 72 23 D8 41 : 46 D0 CD 11 3A 04 B3 8E AF 82 9D BD 51 1E 17 7A : F2 76 2C 2B 86 39 A7 BD D7 8D 1A 53 EC E4 00 D5 : E8 EC A2 36 B1 ED E2 50 E2 32 09 8A 3F 9F 99 25 : 8F B8 4E AB B9 7D D5 96 65 DA 16 A0 C5 BE 0E AE : 44 5B EF 5E F4 A7 29 CB 82 DD AC 44 E9 AA 93 94 : 29 0E F8 18 D6 C8 57 5E F2 76 C4 F2 11 60 38 B9 : 1B 3C 1D 97 C9 6A F1 02 03 01 00 01 : } 338 A3 66: [3] { 340 30 64: SEQUENCE { 342 30 15: SEQUENCE { 344 06 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 349 01 1: BOOLEAN TRUE 352 04 5: OCTET STRING : 30 03 01 01 FF : } 359 30 14: SEQUENCE { 361 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 366 01 1: BOOLEAN TRUE 369 04 4: OCTET STRING : 03 02 01 86 : } 375 30 29: SEQUENCE { 377 06 3: OBJECT IDENTIFIER : subjectKeyIdentifier (2 5 29 14) 382 04 22: OCTET STRING : 04 14 E9 E0 90 27 AC 78 20 7A 9A D3 4C F2 42 37 : 4E 22 AE 9E 38 BB : } : } : } : } 406 30 13: SEQUENCE { 408 06 9: OBJECT IDENTIFIER : sha1withRSAEncryption (1 2 840 113549 1 1 5) 419 05 0: NULL : } 421 03 129: BIT STRING 0 unused bits : B7 9E D4 04 D3 ED 29 E4 FF 89 89 15 2E 4C DB 0C : F0 48 0F 32 61 EE C4 04 EC 12 5D 2D FF 0F 64 59 : 7E 0A C3 ED 18 FD E3 56 40 37 A7 07 B5 F0 38 12 : 61 50 ED EF DD 3F E3 0B B8 61 A5 A4 9B 3C E6 9E : 9C 54 9A B6 95 D6 DA 6C 3B B5 2D 45 35 9D 49 01 : 76 FA B9 B9 31 F9 F9 6B 12 53 A0 F5 14 60 9B 7D : CA 3E F2 53 6B B0 37 6F AD E6 74 D7 DB FA 5A EA : 14 41 63 5D CD BE C8 0E C1 DA 6A 8D 53 34 18 02 : } 553 30 520: SEQUENCE { 557 30 369: SEQUENCE { 561 A0 3: [0] { 563 02 1: INTEGER 2 : } 566 02 16: INTEGER Schaad 10 CertDist May 2000 : 46 34 6B C7 80 00 56 BC 11 D3 6E 2E CD 5D 71 D0 584 30 13: SEQUENCE { 586 06 9: OBJECT IDENTIFIER : sha1withRSAEncryption (1 2 840 113549 1 1 5) 597 05 0: NULL : } 599 30 18: SEQUENCE { 601 31 16: SET { 603 30 14: SEQUENCE { 605 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 610 13 7: PrintableString 'CarlRSA' : } : } : } 619 30 30: SEQUENCE { 621 17 13: UTCTime '990819070000Z' 636 17 13: UTCTime '391231235959Z' : } 651 30 17: SEQUENCE { 653 31 15: SET { 655 30 13: SEQUENCE { 657 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 662 13 6: PrintableString 'BobRSA' : } : } : } 670 30 159: SEQUENCE { 673 30 13: SEQUENCE { 675 06 9: OBJECT IDENTIFIER : rsaEncryption (1 2 840 113549 1 1 1) 686 05 0: NULL : } 688 03 141: BIT STRING 0 unused bits : 30 81 89 02 81 81 00 CA 5C E1 2E EC CF C1 3B 5D : 10 1B DF 54 35 71 99 0A 09 D8 3D E4 61 BF A0 BE : 0A BE 11 A4 3C B5 38 41 41 48 04 E1 5B B1 17 1C : 53 B5 F4 C5 15 D3 FE 0C FB 0C AC EA 80 18 36 03 : 7E 41 93 53 D7 40 74 49 DB D9 C6 AF FE D6 CA 0D : CA 01 84 8F A1 E9 A3 00 21 27 51 D5 40 19 AA E3 : C0 30 78 5B A0 B2 E6 C1 2D 24 36 CB AE 44 10 82 : B0 DD 74 D7 F6 EB 51 27 B2 A7 B6 AD 78 CA A7 1B : 59 51 18 EF 28 0C 53 02 03 01 00 01 : } 832 A3 96: [3] { 834 30 94: SEQUENCE { 836 30 12: SEQUENCE { 838 06 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 843 01 1: BOOLEAN TRUE 846 04 2: OCTET STRING : 30 00 : } 850 30 14: SEQUENCE { 852 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 857 01 1: BOOLEAN TRUE 860 04 4: OCTET STRING Schaad 11 CertDist May 2000 : 03 02 05 20 : } 866 30 31: SEQUENCE { 868 06 3: OBJECT IDENTIFIER : authorityKeyIdentifier (2 5 29 35) 873 04 24: OCTET STRING : 30 16 80 14 E9 E0 90 27 AC 78 20 7A 9A D3 4C F2 : 42 37 4E 22 AE 9E 38 BB : } 899 30 29: SEQUENCE { 901 06 3: OBJECT IDENTIFIER : subjectKeyIdentifier (2 5 29 14) 906 04 22: OCTET STRING : 04 14 E8 F4 B8 67 D8 B3 96 A4 2A F3 11 AA 29 D3 : 95 5A 86 16 B4 24 : } : } : } : } 930 30 13: SEQUENCE { 932 06 9: OBJECT IDENTIFIER : sha1withRSAEncryption (1 2 840 113549 1 1 5) 943 05 0: NULL : } 945 03 129: BIT STRING 0 unused bits : 2B 53 8A E0 38 69 0C 19 2D AA D9 42 67 BE 58 49 : A9 58 4C 42 F1 F5 68 B6 4E 4D 07 A4 9E B2 DB D0 : 95 DF 4C F0 EF 5F 23 D6 90 7C 3F 62 92 86 E4 D2 : 64 AB 2E B5 CA 5D 58 57 04 DF 39 29 73 B0 CD A5 : 6B 22 75 C9 5D D5 0B FF C9 B8 7B F0 09 2C A1 86 : F3 75 CD 54 67 AD 8B 1E 7B EC 7E AB 25 2B 14 71 : 98 D1 19 16 F0 60 EB 3B 3C F4 0F 24 98 7A A4 A4 : BA E6 C2 4E 80 07 EA C4 93 92 8B 49 17 FE 42 58 : } 1077 30 667: SEQUENCE { 1081 30 602: SEQUENCE { 1085 A0 3: [0] { 1087 02 1: INTEGER 2 : } 1090 02 1: INTEGER 1 1093 30 9: SEQUENCE { 1095 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 1104 30 18: SEQUENCE { 1106 31 16: SET { 1108 30 14: SEQUENCE { 1110 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 1115 13 7: PrintableString 'CarlDSS' : } : } : } 1124 30 30: SEQUENCE { 1126 17 13: UTCTime '990816225050Z' 1141 17 13: UTCTime '391231235959Z' : } Schaad 12 CertDist May 2000 1156 30 18: SEQUENCE { 1158 31 16: SET { 1160 30 14: SEQUENCE { 1162 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 1167 13 7: PrintableString 'CarlDSS' : } : } : } 1176 30 439: SEQUENCE { 1180 30 299: SEQUENCE { 1184 06 7: OBJECT IDENTIFIER dsa (1 2 840 10040 4 1) 1193 30 286: SEQUENCE { 1197 02 129: INTEGER : 00 B6 49 18 3E 8A 44 C1 29 71 94 4C 01 C4 12 C1 : 7A 79 CB 54 4D AB 1E 81 FB C6 4C B3 0E 94 09 06 : EB 01 D4 B1 C8 71 4B C7 45 C0 50 25 5D 9C FC DA : E4 6D D3 E2 86 48 84 82 7D BA 15 95 4A 16 F6 46 : ED DD F6 98 D2 BB 7E 8A 0A 8A BA 16 7B B9 50 01 : 48 93 8B EB 25 15 51 97 55 DC 8F 53 0E 10 A9 50 : FC 70 B7 CD 30 54 FD DA DE A8 AA 22 B5 A1 AF 8B : CC 02 88 E7 8B 70 5F B9 AD E1 08 D4 6D 29 2D D6 : E9 1329 02 21: INTEGER : 00 DD C1 2F DF 53 CE 0B 34 60 77 3E 02 A4 BF 8A : 5D 98 B9 10 D5 1352 02 128: INTEGER : 0C EE 57 9B 4B BD DA B6 07 6A 74 37 4F 55 7F 9D : ED BC 61 0D EB 46 59 3C 56 0B 2B 5B 0C 91 CE A5 : 62 52 69 CA E1 6D 3E BD BF FE E1 B7 B9 2B 61 3C : AD CB AE 45 E3 06 AC 8C 22 9D 9C 44 87 0B C7 CD : F0 1C D9 B5 4E 5D 73 DE AF 0E C9 1D 5A 51 F5 4F : 44 79 35 5A 73 AA 7F 46 51 1F A9 42 16 9C 48 EB : 8A 79 61 B4 D5 2F 53 22 44 63 1F 86 B8 A3 58 06 : 25 F8 29 C0 EF BA E0 75 F0 42 C4 63 65 52 9B 0A : } : } 1483 03 133: BIT STRING 0 unused bits : 02 81 81 00 99 87 74 27 03 66 A0 B1 C0 AD DC 2C : 75 BB E1 6C 44 9C DA 21 6D 4D 47 6D B1 62 09 E9 : D8 AE 1E F2 3A B4 94 B1 A3 8E 7A 9B 71 4E 00 94 : C9 B4 25 4E B9 60 96 19 24 01 F3 62 0C FE 75 C0 : FB CE D8 68 00 E3 FD D5 70 4F DF 23 96 19 06 94 : F4 B1 61 8F 3A 57 B1 08 11 A4 0B 26 25 F0 52 76 : 81 EA 0B 62 0D 95 2A E6 86 BA 72 B2 A7 50 83 0B : AA 27 CD 1B A9 4D 89 9A D7 8D 18 39 84 3F 8B C5 : 56 4D 80 7A : } 1619 A3 66: [3] { 1621 30 64: SEQUENCE { 1623 30 15: SEQUENCE { 1625 06 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 1630 01 1: BOOLEAN TRUE 1633 04 5: OCTET STRING : 30 03 01 01 FF : } Schaad 13 CertDist May 2000 1640 30 14: SEQUENCE { 1642 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 1647 01 1: BOOLEAN TRUE 1650 04 4: OCTET STRING : 03 02 01 86 : } 1656 30 29: SEQUENCE { 1658 06 3: OBJECT IDENTIFIER : subjectKeyIdentifier (2 5 29 14) 1663 04 22: OCTET STRING : 04 14 70 44 3E 82 2E 6F 87 DE 4A D3 75 E3 3D 20 : BC 43 2B 93 F1 1F : } : } : } : } 1687 30 9: SEQUENCE { 1689 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 1698 03 48: BIT STRING 0 unused bits : 30 2D 02 14 6B A9 F0 4E 7A 5A 79 E3 F9 BE 3D 2B : C9 06 37 E9 11 17 A1 13 02 15 00 8F 34 69 2A 8B : B1 3C 03 79 94 32 4D 12 1F CE 89 FB 46 B2 3B : } 1748 30 734: SEQUENCE { 1752 30 669: SEQUENCE { 1756 A0 3: [0] { 1758 02 1: INTEGER 2 : } 1761 02 2: INTEGER 200 1765 30 9: SEQUENCE { 1767 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 1776 30 18: SEQUENCE { 1778 31 16: SET { 1780 30 14: SEQUENCE { 1782 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 1787 13 7: PrintableString 'CarlDSS' : } : } : } 1796 30 30: SEQUENCE { 1798 17 13: UTCTime '990817011049Z' 1813 17 13: UTCTime '391231235959Z' : } 1828 30 19: SEQUENCE { 1830 31 17: SET { 1832 30 15: SEQUENCE { 1834 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 1839 13 8: PrintableString 'AliceDSS' : } : } : } 1849 30 438: SEQUENCE { 1853 30 299: SEQUENCE { Schaad 14 CertDist May 2000 1857 06 7: OBJECT IDENTIFIER dsa (1 2 840 10040 4 1) 1866 30 286: SEQUENCE { 1870 02 129: INTEGER : 00 81 8D CD ED 83 EA 0A 9E 39 3E C2 48 28 A3 E4 : 47 93 DD 0E D7 A8 0E EC 53 C5 AB 84 08 4F FF 94 : E1 73 48 7E 0C D6 F3 44 48 D1 FE 9F AF A4 A1 89 : 2F E1 D9 30 C8 36 DE 3F 9B BF B7 4C DC 5F 69 8A : E4 75 D0 37 0C 91 08 95 9B DE A7 5E F9 FC F4 9F : 2F DD 43 A8 8B 54 F1 3F B0 07 08 47 4D 5D 88 C3 : C3 B5 B3 E3 55 08 75 D5 39 76 10 C4 78 BD FF 9D : B0 84 97 37 F2 E4 51 1B B5 E4 09 96 5C F3 7E 5B : DB 2002 02 21: INTEGER : 00 E2 47 A6 1A 45 66 B8 13 C6 DA 8F B8 37 21 2B : 62 8B F7 93 CD 2025 02 128: INTEGER : 26 38 D0 14 89 32 AA 39 FB 3E 6D D9 4B 59 6A 4C : 76 23 39 04 02 35 5C F2 CB 1A 30 C3 1E 50 5D DD : 9B 59 E2 CD AA 05 3D 58 C0 7B A2 36 B8 6E 07 AF : 7D 8A 42 25 A7 F4 75 CF 4A 08 5E 4B 3E 90 F8 6D : EA 9C C9 21 8A 3B 76 14 E9 CE 2E 5D A3 07 CD 23 : 85 B8 2F 30 01 7C 6D 49 89 11 89 36 44 BD F8 C8 : 95 4A 53 56 B5 E2 F9 73 EC 1A 61 36 1F 11 7F C2 : BD ED D1 50 FF 98 74 C2 D1 81 4A 60 39 BA 36 39 : } : } 2156 03 132: BIT STRING 0 unused bits : 02 81 80 5C E3 B9 5A 75 14 96 0B A9 7A DD E3 3F : A9 EC AC 5E DC BD B7 13 11 34 A6 16 89 28 11 23 : D9 34 86 67 75 75 13 12 3D 43 5B 6F E5 51 BF FA : 89 F2 A2 1B 3E 24 7D 3D 07 8D 5B 63 C8 BB 45 A5 : A0 4A E3 85 D6 CE 06 80 3F E8 23 7E 1A F2 24 AB : 53 1A B8 27 0D 1E EF 08 BF 66 14 80 5C 62 AC 65 : FA 15 8B F1 BB 34 D4 D2 96 37 F6 61 47 B2 C4 32 : 84 F0 7E 41 40 FD 46 A7 63 4E 33 F2 A5 E2 F4 F2 : 83 E5 B8 : } 2291 A3 131: [3] { 2294 30 128: SEQUENCE { 2297 30 32: SEQUENCE { 2299 06 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17) 2304 04 25: OCTET STRING : 30 17 81 15 61 6C 69 63 65 44 73 73 40 65 78 61 : 6D 70 6C 65 73 2E 63 6F 6D : } 2331 30 12: SEQUENCE { 2333 06 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 2338 01 1: BOOLEAN TRUE 2341 04 2: OCTET STRING : 30 00 : } 2345 30 14: SEQUENCE { 2347 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 2352 01 1: BOOLEAN TRUE 2355 04 4: OCTET STRING Schaad 15 CertDist May 2000 : 03 02 06 C0 : } 2361 30 31: SEQUENCE { 2363 06 3: OBJECT IDENTIFIER : authorityKeyIdentifier (2 5 29 35) 2368 04 24: OCTET STRING : 30 16 80 14 70 44 3E 82 2E 6F 87 DE 4A D3 75 E3 : 3D 20 BC 43 2B 93 F1 1F : } 2394 30 29: SEQUENCE { 2396 06 3: OBJECT IDENTIFIER : subjectKeyIdentifier (2 5 29 14) 2401 04 22: OCTET STRING : 04 14 BE 6C A1 B3 E3 C1 F7 ED 43 70 A4 CE 13 01 : E2 FD E3 97 FE CD : } : } : } : } 2425 30 9: SEQUENCE { 2427 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 2436 03 48: BIT STRING 0 unused bits : 30 2D 02 15 00 98 B0 C6 3F CF 71 47 5A 35 A9 4A : 8F C0 F8 24 05 E8 46 94 8E 02 14 5B 9F 48 C0 8C : A1 C1 02 9C 44 EA E9 A1 87 C1 A5 7F 28 2D BB : } 2486 30 866: SEQUENCE { 2490 30 801: SEQUENCE { 2494 A0 3: [0] { 2496 02 1: INTEGER 2 : } 2499 02 2: INTEGER 201 2503 30 9: SEQUENCE { 2505 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 2514 30 18: SEQUENCE { 2516 31 16: SET { 2518 30 14: SEQUENCE { 2520 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 2525 13 7: PrintableString 'CarlDSS' : } : } : } 2534 30 30: SEQUENCE { 2536 17 13: UTCTime '990817011828Z' 2551 17 13: UTCTime '391231235959Z' : } 2566 30 16: SEQUENCE { 2568 31 14: SET { 2570 30 12: SEQUENCE { 2572 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 2577 13 5: PrintableString 'bobDH' : } : } Schaad 16 CertDist May 2000 : } 2584 30 578: SEQUENCE { 2588 30 439: SEQUENCE { 2592 06 7: OBJECT IDENTIFIER : dhPublicNumber (1 2 840 10046 2 1) 2601 30 426: SEQUENCE { 2605 02 129: INTEGER : 00 EC 2C CD A4 EF 9A 26 2F 62 A7 BB 23 4D DF 2B : 25 C1 68 D2 9E A9 45 5B 36 F1 94 89 1A AF 7D 11 : 24 9D 3D B9 3C 29 E8 D7 23 80 33 A6 9E 45 02 BB : AA CC 9E 28 05 95 A0 B3 17 76 C1 F7 25 35 61 02 : 41 92 27 0C 5E AE 48 E5 F3 6E 38 EF 91 D1 CF 37 : FE 9A 40 97 C8 2D 35 9E 9D 93 C6 F8 15 AF 3F DA : 74 3A B7 C4 93 B5 B9 BB 76 6C 1F A8 7E BC 3A AA : 43 0A 81 64 FC 63 F0 7B 71 98 FA C0 38 79 10 1A : 33 2737 02 129: INTEGER : 00 BA 0B D7 74 3D E7 34 E5 4C 13 A7 95 96 BB F1 : E4 61 37 08 FB 12 C7 FB 9C 91 77 06 99 35 F0 48 : 24 96 33 12 01 7E 8D EC 0B F6 B2 C0 63 A7 15 C5 : 5E 95 86 A2 73 C5 49 46 37 79 60 FD 77 05 09 48 : 9B 70 8D 3C 05 F6 CE 44 2C 7F 7D 1B 2B 15 DD F3 : 05 2F BE 85 20 8F 8D F9 B4 A0 45 74 2B F4 3B 9D : 42 62 34 27 27 81 8E 6F 0F 5E 62 85 89 CC ED 21 : C3 91 70 06 54 EE 70 A8 92 55 5B 6E 19 22 4D 62 : A7 2869 02 33: INTEGER : 00 C3 AB 4A 30 79 B3 D3 97 4E CA F5 A2 7D C7 70 : A3 45 F3 B3 A2 86 05 D2 3E 49 F9 9F D9 0A B3 BE : BD 2904 02 97: INTEGER : 01 34 FE C2 33 48 EB F6 3B 97 D9 E4 97 A7 60 A5 : 25 69 34 FB FD 46 2A D6 C9 C4 C5 F7 D6 F4 04 19 : 8D 94 D9 8A 37 68 69 67 55 FB F2 6B 0E 47 C5 5B : 0B 4B 0E 1C 1A 8B 7B 75 B7 AA C3 AA D7 EB 3B DA : 2A 8D 02 87 37 47 83 D7 31 B4 25 A8 AC BB 11 88 : 53 1C 11 92 B6 69 E7 2E 90 C1 7A FC 87 F4 F6 D7 : 1A 3003 30 26: SEQUENCE { 3005 03 21: BIT STRING 0 unused bits : B9 FF 1C 93 44 67 37 D1 B2 F8 57 9A 32 4A C9 4A : FF 3B EC 1E 3028 02 1: INTEGER 29 : } : } : } 3031 03 132: BIT STRING 0 unused bits : 02 81 80 6F D4 F6 CD 94 9A 6E AF 5B 57 17 96 75 : BB 0F B9 48 E9 90 37 0D 15 20 C2 55 1E 13 E2 AE : 71 17 84 C3 0E 74 AE 8A 55 7F 28 7D 8B D7 28 22 : 9C 76 46 D7 3B 4F 9D D1 4D 1B B2 DB 51 94 C5 6D : 54 96 40 38 8A 38 81 63 4A 8C C3 1E 09 89 74 A6 : 58 D5 C8 5A 3D CF BB B8 23 7F 9C 1F 7D 78 FA 9E : F9 90 9E 91 E7 4B C2 A4 BE 45 06 78 42 58 3D 9F : 63 2C EF 84 D4 67 E5 FB C6 6D A2 36 29 67 90 46 Schaad 17 CertDist May 2000 : DB 4E 48 : } 3166 A3 127: [3] { 3168 30 125: SEQUENCE { 3170 30 29: SEQUENCE { 3172 06 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17) 3177 04 22: OCTET STRING : 30 14 81 12 62 6F 62 44 68 40 65 78 61 6D 70 6C : 65 73 2E 63 6F 6D : } 3201 30 12: SEQUENCE { 3203 06 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 3208 01 1: BOOLEAN TRUE 3211 04 2: OCTET STRING : 30 00 : } 3215 30 14: SEQUENCE { 3217 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 3222 01 1: BOOLEAN TRUE 3225 04 4: OCTET STRING : 03 02 03 08 : } 3231 30 31: SEQUENCE { 3233 06 3: OBJECT IDENTIFIER : authorityKeyIdentifier (2 5 29 35) 3238 04 24: OCTET STRING : 30 16 80 14 70 44 3E 82 2E 6F 87 DE 4A D3 75 E3 : 3D 20 BC 43 2B 93 F1 1F : } 3264 30 29: SEQUENCE { 3266 06 3: OBJECT IDENTIFIER : subjectKeyIdentifier (2 5 29 14) 3271 04 22: OCTET STRING : 04 14 26 FF 19 48 C3 59 33 68 56 8D 7E C8 80 68 : 5C CF 3C 72 DD 26 : } : } : } : } 3295 30 9: SEQUENCE { 3297 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 3306 03 48: BIT STRING 0 unused bits : 30 2D 02 14 15 EA 15 43 E3 49 22 86 C1 BB E5 DA : E4 0E B8 09 E0 D5 72 35 02 15 00 AE 4F 51 29 73 : 71 75 A9 81 EB ED 9D 5E 00 19 7E F0 DE 5A D6 : } : } 3356 31 283: SET { 3360 30 279: SEQUENCE { 3364 02 1: INTEGER 1 3367 30 24: SEQUENCE { 3369 30 18: SEQUENCE { 3371 31 16: SET { 3373 30 14: SEQUENCE { Schaad 18 CertDist May 2000 3375 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 3380 13 7: PrintableString 'CarlDSS' : } : } : } 3389 02 2: INTEGER 200 : } 3393 30 9: SEQUENCE { 3395 06 5: OBJECT IDENTIFIER sha1 (1 3 14 3 2 26) 3402 05 0: NULL : } 3404 A0 176: [0] { 3407 30 26: SEQUENCE { 3409 06 9: OBJECT IDENTIFIER : contentType (1 2 840 113549 1 9 3) 3420 31 13: SET { 3422 06 11: OBJECT IDENTIFIER : id-ct-publishCert (1 2 840 113549 1 9 16 1 3) : } : } 3435 30 35: SEQUENCE { 3437 06 9: OBJECT IDENTIFIER : messageDigest (1 2 840 113549 1 9 4) 3448 31 22: SET { 3450 04 20: OCTET STRING : DA 39 A3 EE 5E 6B 4B 0D 32 55 BF EF 95 60 18 90 : AF D8 07 09 : } : } 3472 30 109: SEQUENCE { 3474 06 11: OBJECT IDENTIFIER : id-aa-smimeEncryptCerts (1 2 840 113549 1 9 16 2 13) 3487 31 94: SET { 3489 30 92: SEQUENCE { 3491 30 36: SEQUENCE { 3493 04 20: OCTET STRING : 3B F6 B5 69 50 7E 3E AD 03 97 F8 F8 29 DD A0 B9 : 8A CF DA 9B 3515 30 12: SEQUENCE { 3517 30 10: SEQUENCE { 3519 06 8: OBJECT IDENTIFIER : des-EDE3-CBC (1 2 840 113549 3 7) : } : } : } 3529 30 52: SEQUENCE { 3531 04 20: OCTET STRING : E4 B8 2D 17 E4 23 D5 22 F0 58 BD 73 BD 3D 59 76 : AF C6 18 C8 3553 30 28: SEQUENCE { 3555 30 10: SEQUENCE { 3557 06 8: OBJECT IDENTIFIER : des-EDE3-CBC (1 2 840 113549 3 7) : } Schaad 19 CertDist May 2000 3567 30 14: SEQUENCE { 3569 06 8: OBJECT IDENTIFIER : rc2CBC (1 2 840 113549 3 2) 3579 02 2: INTEGER 160 : } : } : } : } : } : } : } 3583 30 9: SEQUENCE { 3585 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) : } 3594 04 47: OCTET STRING : 30 2D 02 15 00 B7 D1 AD F0 EF F6 49 30 F9 9F 9C : 55 74 E0 60 56 65 B4 14 15 02 14 37 B4 90 1F 00 : 8A F6 F7 41 8B CF AF 90 E6 F3 8E 4D A0 7A 30 : } : } : } : } : } References CMS Housley, R., "Cryptographic Message Syntax" RFC 2630, June 1999. MUSTSHOULD Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", RFC 2119 , March 1997. SMIME Ramsdell, B., "S/MIME Version 3 Message Specification", RFC 2633, June 1999. SMIMECERT Ramsdell, B., "S/MIME Version 3 Certificate Handling", RFC 2632, June 1999. Security Considerations This entire document discusses security. Some items of special note are: Implementations must protect the signer's private key. Compromise of the signer's private key permits masquerading and therefore substitution of encryption certificates. Implementations must do appropriate checking that the entity named in a certificate is the same entity that the encrypted message is destined for to protect contents of encrypted messages. Author Address Jim Schaad Jimsch@exmsft.com Schaad 20 http://www.nwlink.com