PKCS. PKCS: Public Key Cryptography Standards

Transcription

1 : Public Key Cryptography Standards Devised and published by RSA Security Launched in 1991 as implementation agreements among early adopters of public-key cryptography Apple, Digital, Lotus, Microsoft, MIT, Northern Telecom, Novell, Sun Revised 1993, Cryptoki ( #11) released 1995 Workshops, ongoing updates, new documents since Standards #1 : RSA Cryptography Standard #3 : Diffie-Hellman Key-Agreement #5 : Password-Based Cryptography #7 : Cryptographic Message Syntax Standard Sign/encrypt messages under a PKI #8 : Private-Key Information Syntax #9 : Selected Attribute Types selected attribute types for use in #7, #8, #10 #10: Certification Request Syntax Format of messages sent to a certification authority to request certification of a public key #11: Cryptographic Token Interface (Cryptoki) #12: Personal Information Exchange Syntax #13: Elliptic Curve Cryptography Standard #14: Pseudo-random Number Generation #15: Cryptographic Token Information Format Standard Obsolete: #2, #4, #6 2

2 #1: RSA Cryptography RSA encryption, signature schemes v1.5 (1993) has basic RSA schemes, specified in SSL, S/MIME, PKIX v2.0 (1998) adds Bellare-Rogaway OAEP encryption v2.1 (2002) adds B-R PSS (Probabilistic Signature Scheme) #7: Cryptographic Message Syntax Signed, encrypted message syntax enhancement to Privacy-Enhanced Mail v1.5 (1993) has RSA-oriented key management, basis for S/MIME, some PKIX protocols IETF RFC 2630 (CMS) adds DH-oriented key management v1.6 (2009) supports SET (Secure Electronic Transaction) protocol 3 : Cryptographic Token Interface (a.k.a. Cryptoki) Programming interface for smart cards, other devices v1.0 (1995) has basic methods v2.01 (1997) adds cryptographic mechanisms, improves management v2.11 (2001) clarifies interfaces, adds more mechanisms - Main Goals: The primary goal of Cryptoki: a lower-level programming interface that abstracts the details of the devices; and presents to the application a common model of the cryptographic device, called a cryptographic token. A secondary goal: resource-sharing» as desktop multi-tasking operating systems become more popular, a single device should be shared between more than one application. In addition, an application should be able to interface to more than one device at a given time. 4

3 11 and several key concepts Slot place where the smart card is inserted Token thing, which is inserted into the Slot. Commonly the Smart Cards Object keys, certificates, data, sessions, etc. Session before any operation we need to establish a session to the token Object Data Key Certificate Public Key Private Key Secret Key 5 - Functions SmarCard Management:» C_GetSlotList» C_GetSlotInfo» C_GetTokenInfo» C_GetMechanismList» C_GetMechanismInfo» C_InitToken» C_InitPIN» C_SetPIN Digital Signature:» C_SignInit» C_Sign» C_SignUpdate» C_SignFinal» C_VerifyInit» C_Verify» C_VerifyUpdate» C_VerifyFinal Session Managment:» C_OpenSession» C_CloseSession» C_CloseAllSession» C_GetSessionInfo» C_Login» C_Logout Key Management:» C_GenerateKey» C_GenerateKeyPair» C_WrapKey» C_UnwrapKey Message Hashing:» C_DigestInit» C_Digest» C_DigestUpdate» C_DigestFinal 6

4 example Management of SmartCard - Generation of a public/private key pair: the C_GenerateKeyPair function performs the following operations: 1. Inserts the file EF_Index identification of key items obtained from templates; 2. Compiles the files EF_Kpub_Attribute and EF_Kpri_Attribute with information obtained from templates; 3. Constructs the file via the APDU command: EF_Kpub: CREATE FILE; 4. Constructs the object BSOKPRI-SIGN through the APDU command: APDU: PUT DATA OCI forcing algorithm and conditions of access consistent with the template of the private key; 5. Generates the key pair using the APDU command: APDU: GENERATE KEY PAIR. 7 example The C_GenerateKeyPair (pre-requisite? C_Login) Input Parameters: CK_SESSION_HANDLE hsession:» session handle obtained by the functions C_OpenSession and C_GetSessionInfo; CK_MECHANISM_PTR pmechanism:» pointer to the cryptographic mechanisms supported by the library; CK_ATTRIBUTE_PTR ppublickeytemplate:» pointer to the template of the public key; CK_ULONG ulpublickeyattributecount:» number of attributes of the template; CK_ATTRIBUTE_PTR pprivatekeytemplate:» pointer to the template of the private key; CK_ULONG ulprivatekeyattributecount:» number of attributes of the template; CK_OBJECT_HANDLE_PTR phpublickey:» pointer to where the library will return the object handle public key; CK_OBJECT_HANDLE_PTR phprivatekey:» pointer to where the library will return the object handle private key. CK_RV CK_ENTRY C_GenerateKeyPair ( CK_SESSION_HANDLE hsession, CK_MECHANISM_PTR pmechanism, CK_ATTRIBUTE_PTR ppublickeytemplate, CK_ULONG ulpublickeyattributecount, CK_ATTRIBUTE_PTR pprivatekeytemplate, CK_ULONG ulprivatekeyattributecount, CK_OBJECT_HANDLE_PTR phpublickey, CK_OBJECT_HANDLE_PTR phprivatekey ); 8

5 #15 #15: Cryptographic Token Information Format File format for cryptographic data on smart cards, other devices v1.0 (1998) newly released, candidate for WAP Forum, country e-id cards v1.1 (2004), adds software format Common formats for cryptographic objects File formats in case of smart cards Coordination with several groups:» WAP Forum» PC/SC Forum» SEIS (Sweden) 9 #15 - File System EF_Index: Elementary Linear File type TLV that contains identifiers # 11 (CKA_ID) objects public key, private key, certificates, and data objects in the Digital Signature directory. This file is used by the object management functions for the "navigation" of the Smart Card file system. 10

6 Abstraction: APPLICATION COM Ser.Provider C - API Crypto Service Provider Resource Manager IFD Driver OS manufacture IFD SC reader Smart Card 11 Abstraction in Windows - Cryptographic Service Provider (CSP): 12