Storing PKI Credentials
Storing PKI Credentials
Last Updated: July 18, 2012
Public key infrastructure (PKI) credentials, such as Rivest, Shamir, and Adelman (RSA) keys and certificates can be stored in a specific location on the router, such as NVRAM and flash memory or on a USB eTtoken 64 KB smart card. USB tokens provide secure configuration distribution, RSA operations such as on-token key generation, signing, and authentication, and the storage of Virtual Private Network (VPN) credentials for deployment.
Finding Feature Information
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for Storing PKI Credentials
Prerequisites for Specifying a Local Certificate Storage Location
Before you can specify the local certificate storage location, your system should meet the following requirements:
Prerequisites for Specifying USB Token Storage for PKI Credentials
Before you can use a USB token, your system should meet the following requirements:
Restrictions for Storing PKI Credentials
Restrictions for Specifying a Local Certificate Storage Location
When storing certificates to a local storage location, the following restrictions are applicable:
Restrictions for Specifying USB Token Storage
When using a USB token to store PKI data, the following restrictions are applicable:
Information About Storing PKI Credentials
Storing Certificates to a Local Storage Location
Certificates are stored to NVRAM by default; however, some routers do not have the required amount of NVRAM to successfully store certificates.
All Cisco platforms support NVRAM and flash local storage. Depending on your platform, you may have other supported local storage options including bootflash, slot, disk, USB flash, or USB token.
During run time, you can specify what active local storage device you would like to use to store certificates.
PKI Credentials and USB Tokens
To use a secure USB token on your router, you should understand the following concepts:
How a USB Token Works
A smart card is a small plastic card, containing a microprocessor and memory that allows you to store and process data. A USB token is a smart card with a USB interface. The token can securely store any type of file within its available storage space (32 KB). Configuration files that are stored on the USB token can be encrypted and accessed only via a user PIN. The device does not load the configuration file unless the proper PIN has been configured for secure deployment of device configuration files.
After you plug the USB token into the device, you must log into the USB token; thereafter, you can change default settings, such as the user PIN (default: 1234567890) and the allowed number of failed login attempts (default: 15 attempts) before future logins are refused. For more information on accessing and configuring the USB token, see the section "Logging Into and Setting Up the USB Token."
After you have successfully logged into the USB token, you can copy files from the device on to the USB token via the copy command. USB token RSA keys and associated IPsec tunnels remain available until the device is reloaded. To specify the length of time before the keys are removed and the IPsec tunnels are torn down, issue the crypto pki token removal timeout command. The default timeout is zero, which causes the RSA keys to be removed automatically after the eToken is removed from the device. The default appears in the running configuration as:
crypto pki token default removal timeout 0
The table below highlights the capabilities of the USB token.
Benefits of USB Tokens
USB token support on a Cisco router provides the following application benefits:
Removable Credentials: Provide or Store VPN Credentials on an External Device for Deployment
A USB token can use smart card technology to store a digital certificate and configuration for IPsec VPN deployment. This ability enhances the capability of the router to generate RSA public keys to authenticate at least one IPsec tunnel. (Because a router can initiate multiple IPsec tunnels, the USB token can contain several certificates, as appropriate.)
Storing VPN credentials on an external device reduces the threat of compromising secure data.
PIN Configuration for Secure File Deployment
A USB token can store a configuration file that can be used for enabling encryption on the router via a user-configured PIN. (That is, no digital certificates, preshared keys, or VPNs are used.)
Touchless or Low Touch Configuration
The USB token can provide remote software configuration and provisioning with little or no human interaction. Configuration is set up as an automated process. That is, the USB token can store a bootstrap configuration that the router can use to boot from after the USB token has been inserted into the router. The bootstrap configuration connects the router to a TFTP server, which contains a configuration that completely configures the router.
A USB token may be used as a cryptographic device in addition to a storage device. Using a USB token as a cryptographic device allows RSA operations such as key generation, signing, and authentication to be performed on the token.
General-purpose, special-usage, encryption, or signature RSA key pairs with a modulus of 2048 bits or less may be generated from credentials located on your token storage device. Private keys are not distributed and remain on the token by default, however you may configure the private key storage location.
Keys that reside on a USB token are saved to persistent token storage when they are generated. Key deletion will remove the keys stored on the token from persistent storage immediately. (Keys that do not reside on a token are saved to or deleted from non-token storage locations when the write memory or a similar command is issued.)
Remote Device Configuration and Provisioning in a Secure Device Provisioning (SDP) Environment
SDP may be used to configure a USB token. The configured USB token may be transported to provision a device at a remote location. That is, a USB token may be used to transfer cryptographic information from one network device to another remote network device providing a solution for a staged USB token deployment.
For information about using USB tokens with SDP, see document titles in the "Additional References" section.
How to Configure PKI Storage
Specifying a Local Storage Location for Certificates
Setting Up and Using USB Tokens on Cisco Devices
Storing the Configuration on a USB Token
Logging Into and Setting Up the USB Token
How RSA Keys are Used with a USB Token
Automatic login allows the router to completely come back up without any user or operator intervention. The PIN is stored in the private NVRAM, so it is not visible in the startup or running configuration.
Configuring the Device for Manual Login
Unlike automatic login, manual login requires that the user know the actual USB token PIN.
Manual login can be used when storing a PIN on the device is not desirable. Manual login may also be suitable for some initial deployment or hardware replacement scenarios for which the device is obtained from the local supplier or drop-shipped to the remote site. Manual login can be executed with or without privileges, and it creates files and RSA keys on the USB token available to the Cisco IOS software. If a secondary configuration file is configured, it is executed only with the privileges of the user who is performing the login. Thus, if you want to use manual login and set up the secondary configuration on the USB token to perform anything useful, you need to enable privileges.
Manual login can also be used in recovery scenarios for which the device configuration has been lost. If the scenario contains a remote site that normally connects to the core network with a VPN, the loss of the configuration and RSA keys requires out-of-band services that the USB token can provide. The USB token can contain a boot configuration, a secondary configuration, or both, and RSA keys to authenticate the connection.
What to Do Next
After you have logged into the USB token, it is available for use.
Configuring the USB Token
After you have set up automatic login, you may perform this task to further configure the USB token.
PINs and Passphrases
For additional PIN security with automatic login, you may encrypt your PIN stored in NVRAM and set up a passphrase for your USB token. Establishing a passphrase allows you to keep your PIN secure; another user needs only to know the passphrase, not the PIN.
When the USB token is inserted into the device, the passphrase is needed to decrypt the PIN. Once the PIN is decrypted, the device can then use the PIN to log in to the USB token.
Unlocking and Locking the USB Token
The USB token itself can be locked (encrypted) or unlocked (decrypted).
Unlocking the USB token allows it to be used. Once unlocked, Cisco IOS software treats the token as if it were automatically logged in. Any keys on the USB token are loaded, and if a secondary configuration file is on the token, it is executed with full user privileges (privilege level 15) independent of the privilege level of the logged-in user.
Locking the token, unlike logging out of the token, deletes any RSA keys loaded from the token and runs the secondary unconfiguration file, if configured.
Secondary Configuration and Unconfiguration Files
Configuration files that exist on a USB token are called secondary configuration files. If you create and configure a secondary configuration file, it is executed after the token is logged in. The existence of a secondary configuration file is determined by the presence of a secondary configuration file option in the Cisco IOS configuration stored in NVRAM. When the token is removed or logged out and the removal timer expires, a separate secondary unconfiguration file is processed to remove all secondary configuration elements from the running configuration. Secondary configuration and secondary unconfiguration files are executed at privilege level 15 and are not dependent on the level of the user logged in.
The following example shows both the configuration and encryption of a user PIN and then the device reloading and the user PIN being unlocked:
! Configuring the user PIN Enter configuration commands, one per line. End with CNTL/Z. Device(config)# crypto pki token usbtoken0: userpin Enter password: mypassword ! Encrypt the user PIN Device(config)# crypto pki token usbtoken0: encrypted-user-pin Enter passphrase: mypassphrase Device(config)# exit Device# Sep 20 21:51:38.076: %SYS-5-CONFIG_I: Configured from console by console Device# show running config crypto pki token usbtoken0 user-pin *encrypted* ! Reloading the router. Device> enable Password: ! Decrypting the user pin. Device# crypto pki token usbtoken0: unlock Token eToken is usbtoken0 Enter passphrase: mypassphrase Token login to usbtoken0(eToken) successful Device# Sep 20 22:31:13.128: %CRYPTO-6-TOKENLOGIN: Cryptographic Token eToken Login Successful
The following example shows a how a secondary unconfiguration file might be used to remove secondary configuration elements from the running configuration. For example, a secondary configuration file might be used to set up a PKI trustpoint. A corresponding unconfiguration file, named mysecondaryunconfigfile.cfg, might contain this command line:
no crypto pki trustpoint token-tp
If the token were removed and the following commands executed, the trustpoint and associated certificates would be removed from the device's running configuration:
Device# configure terminal Device(config)# no crypto pki token mytoken secondary unconfig mysecondaryunconfigfile.cfg
What to Do Next
After you have logged into and configured the USB token, it is available for use. If you want to perform USB token administrative tasks, such as changing the user PIN, copying files from the router to the USB token set key storage location, and changing USB tokens, see the "Setting Administrative Functions on the USB Token" section.
Setting Administrative Functions on the USB Token
Perform this task to change default settings, such as the user PIN, the maximum number of failed attempts on the USB token, or the credential storage location.
Troubleshooting USB Tokens
This section contains descriptions of the following Cisco IOS commands that can be used to help troubleshoot possible problems that may arise while using a USB token:
Troubleshooting the USB Port Connection
Use the show file systems command to determine whether the router recognizes that there is a USB module plugged into a USB port. The USB module should appear on the list of file systems. If the module does not appear on the list, it can indicate any of the following problems:
Sample output from the show file systems command showing a USB token appears below. The USB module listing appears in the last line of the examples.
Device# show file systems File Systems: Size(b) Free(b) Type Flags Prefixes - - opaque rw archive: - - opaque rw system: - - opaque rw null: - - network rw tftp: * 129880064 69414912 disk rw flash:# 491512 486395 nvram rw nvram: - - opaque wo syslog: - - opaque rw xmodem: - - opaque rw ymodem: - - network rw rcp: - - network rw pram: - - network rw ftp: - - network rw http: - - network rw scp: - - network rw https: - - opaque ro cns: 63158272 33037312 usbflash rw usbflash0: 32768 858 usbtoken rw usbtoken1:
Determining if a USB Token is Supported by Cisco
Use the show usb device command to determine if a USB token is supported by Cisco. The following output from this command indicates whether or not the module is supported is bold in the sample output below:
Router# show usb device Host Controller:1 Address:0x11 Device Configured:YES Device Supported:YES Description:eToken Pro 4254 Manufacturer:AKS Version:1.0 Serial Number: Device Handle:0x1010000 USB Version Compliance:1.0 Class Code:0xFF Subclass Code:0x0 Protocol:0x0 Vendor ID:0x529 Product ID:0x514 Max. Packet Size of Endpoint Zero:8 Number of Configurations:1 Speed:Low Selected Configuration:1 Selected Interface:0 Configuration: Number:1 Number of Interfaces:1 Description: Attributes:None Max Power:60 mA Interface: Number:0 Description: Class Code:255 Subclass:0 Protocol:0 Number of Endpoints:0
Determining USB Token Device Problems
Use the show usb controllers command to determine if there is a hardware problem with a USB flash module. If the show usb controllers command displays an error, the error indicates a hardware problem in the USB module.
You can also use the show usb controllers command to verify that copy operations onto a USB flash module are occurring successfully. Issuing the show usb controllers command after performing a file copy should display successful data transfers.
The following sample output for the show usb controllers command displays a working USB flash module:
Router# show usb controllers Name:1362HCD Controller ID:1 Controller Specific Information: Revision:0x11 Control:0x80 Command Status:0x0 Hardware Interrupt Status:0x24 Hardware Interrupt Enable:0x80000040 Hardware Interrupt Disable:0x80000040 Frame Interval:0x27782EDF Frame Remaining:0x13C1 Frame Number:0xDA4C LSThreshold:0x628 RhDescriptorA:0x19000202 RhDescriptorB:0x0 RhStatus:0x0 RhPort1Status:0x100103 RhPort2Status:0x100303 Hardware Configuration:0x3029 DMA Configuration:0x0 Transfer Counter:0x1 Interrupt:0x9 Interrupt Enable:0x196 Chip ID:0x3630 Buffer Status:0x0 Direct Address Length:0x80A00 ATL Buffer Size:0x600 ATL Buffer Port:0x0 ATL Block Size:0x100 ATL PTD Skip Map:0xFFFFFFFF ATL PTD Last:0x20 ATL Current Active PTD:0x0 ATL Threshold Count:0x1 ATL Threshold Timeout:0xFF Int Level:1 Transfer Completion Codes: Success :920 CRC :0 Bit Stuff :0 Stall :0 No Response :0 Overrun :0 Underrun :0 Other :0 Buffer Overrun :0 Buffer Underrun :0 Transfer Errors: Canceled Transfers :2 Control Timeout :0 Transfer Failures: Interrupt Transfer :0 Bulk Transfer :0 Isochronous Transfer :0 Control Transfer:0 Transfer Successes: Interrupt Transfer :0 Bulk Transfer :26 Isochronous Transfer :0 Control Transfer:894 USBD Failures: Enumeration Failures :0 No Class Driver Found:0 Power Budget Exceeded:0 USB MSCD SCSI Class Driver Counters: Good Status Failures :3 Command Fail :0 Good Status Timed out:0 Device not Found:0 Device Never Opened :0 Drive Init Fail :0 Illegal App Handle :0 Bad API Command :0 Invalid Unit Number :0 Invalid Argument:0 Application Overflow :0 Device in use :0 Control Pipe Stall :0 Malloc Error :0 Device Stalled :0 Bad Command Code:0 Device Detached :0 Unknown Error :0 Invalid Logic Unit Num:0 USB Aladdin Token Driver Counters: Token Inserted :1 Token Removed :0 Send Insert Msg Fail :0 Response Txns :434 Dev Entry Add Fail :0 Request Txns :434 Dev Entry Remove Fail:0 Request Txn Fail:0 Response Txn Fail :0 Command Txn Fail:0 Txn Invalid Dev Handle:0 USB Flash File System Counters: Flash Disconnected :0 Flash Connected :1 Flash Device Fail :0 Flash Ok :1 Flash startstop Fail :0 Flash FS Fail :0 USB Secure Token File System Counters: Token Inserted :1 Token Detached :0 Token FS success :1 Token FS Fail :0 Token Max Inserted :0 Create Talker Failures:0 Token Event :0 Destroy Talker Failures:0 Watched Boolean Create Failures:0
Displaying USB Token Infomation
Use the dir command with the filesystem keyword option usbtoken0-9: to display all files, directories, and their permission strings on the USB token.
The following sample output displays directory information for the USB token:
Device# dir usbtoken1: Directory of usbtoken1:/ 2 d--- 64 Dec 22 2032 05:23:40 +00:00 1000 5 d--- 4096 Dec 22 2032 05:23:40 +00:00 1001 8 d--- 0 Dec 22 2032 05:23:40 +00:00 1002 10 d--- 512 Dec 22 2032 05:23:42 +00:00 1003 12 d--- 0 Dec 22 2032 05:23:42 +00:00 5000 13 d--- 0 Dec 22 2032 05:23:42 +00:00 6000 14 d--- 0 Dec 22 2032 05:23:42 +00:00 7000 15 ---- 940 Jun 27 1992 12:50:42 +00:00 mystartup-config 16 ---- 1423 Jun 27 1992 12:51:14 +00:00 myrunning-config 32768 bytes total (858 bytes free)
The following sample output displays directory information for all devices to which the device is aware:
Device# dir all-filesystems Directory of archive:/ No files in directory No space information available Directory of system:/ 2 drwx 0 <no date> its 115 dr-x 0 <no date> lib 144 dr-x 0 <no date> memory 1 -rw- 1906 <no date> running-config 114 dr-x 0 <no date> vfiles No space information available Directory of flash:/ 1 -rw- 30125020 Dec 22 2032 03:06:04 +00:00 c3825-entservicesk9-mz.123-14.T 129880064 bytes total (99753984 bytes free) Directory of nvram:/ 476 -rw- 1947 <no date> startup-config 477 ---- 46 <no date> private-config 478 -rw- 1947 <no date> underlying-config 1 -rw- 0 <no date> ifIndex-table 2 ---- 4 <no date> rf_cold_starts 3 ---- 14 <no date> persistent-data 491512 bytes total (486395 bytes free) Directory of usbflash0:/ 1 -rw- 30125020 Dec 22 2032 05:31:32 +00:00 c3825-entservicesk9-mz.123-14.T 63158272 bytes total (33033216 bytes free) Directory of usbtoken1:/ 2 d--- 64 Dec 22 2032 05:23:40 +00:00 1000 5 d--- 4096 Dec 22 2032 05:23:40 +00:00 1001 8 d--- 0 Dec 22 2032 05:23:40 +00:00 1002 10 d--- 512 Dec 22 2032 05:23:42 +00:00 1003 12 d--- 0 Dec 22 2032 05:23:42 +00:00 5000 13 d--- 0 Dec 22 2032 05:23:42 +00:00 6000 14 d--- 0 Dec 22 2032 05:23:42 +00:00 7000 15 ---- 940 Jun 27 1992 12:50:42 +00:00 mystartup-config 16 ---- 1423 Jun 27 1992 12:51:14 +00:00 myrunning-config 32768 bytes total (858 bytes free)
Configuration Examples for PKI Storage
Example: Storing Certificates to a Specific Local Storage Location
The following configuration example shows how to store certificates to the certs subdirectory. The certs subdirectory does not exist and is automatically created.
Router# dir nvram: 114 -rw- 4687 <no date> startup-config 115 ---- 5545 <no date> private-config 116 -rw- 4687 <no date> underlying-config 1 ---- 34 <no date> persistent-data 3 -rw- 707 <no date> ioscaroot#7401CA.cer 9 -rw- 863 <no date> msca-root#826E.cer 10 -rw- 759 <no date> msca-root#1BA8CA.cer 11 -rw- 863 <no date> msca-root#75B8.cer 24 -rw- 1149 <no date> storagename#6500CA.cer 26 -rw- 863 <no date> msca-root#83EE.cer 129016 bytes total (92108 bytes free) Router# configure terminal Enter configuration commands, one per line. End with CNTL/Z. Router(config)# crypto pki certificate storage disk0:/certs Requested directory does not exist -- created Certificates will be stored in disk0:/certs/ Router(config)# end Router# write *May 27 02:09:00:%SYS-5-CONFIG_I:Configured from console by consolemem Building configuration... [OK] Router# directory disk0:/certs Directory of disk0:/certs/ 14 -rw- 707 May 27 2005 02:09:02 +00:00 ioscaroot#7401CA.cer 15 -rw- 863 May 27 2005 02:09:02 +00:00 msca-root#826E.cer 16 -rw- 759 May 27 2005 02:09:02 +00:00 msca-root#1BA8CA.cer 17 -rw- 863 May 27 2005 02:09:02 +00:00 msca-root#75B8.cer 18 -rw- 1149 May 27 2005 02:09:02 +00:00 storagename#6500CA.cer 19 -rw- 863 May 27 2005 02:09:02 +00:00 msca-root#83EE.cer 47894528 bytes total (20934656 bytes free) ! The certificate files are now on disk0/certs:
Example: Logging Into a USB Token and Saving RSA Keys to the USB Token
The following configuration example shows to how log in to the USB token, generate RSA keys, and store the RSA keys on the USB token:
! Configure the router to automatically log into the eToken configure terminal crypto pki token default user-pin 0 1234567890 ! Generate RSA keys and enroll certificates with the CA. crypto pki trustpoint IOSCA enrollment url http://10.23.2.2 exit crypto ca authenticate IOSCA Certificate has the following attributes: Fingerprint MD5:23272BD4 37E3D9A4 236F7E1A F534444E Fingerprint SHA1:D1B4D9F8 D603249A 793B3CAF 8342E1FE 3934EB7A % Do you accept this certificate? [yes/no]:yes Trustpoint CA certificate accepted. crypto pki enroll crypto pki enroll IOSCA % % Start certificate enrollment .. % Create a challenge password. You will need to verbally provide this password to the CA Administrator in order to revoke your certificate. For security reasons your password will not be saved in the configuration. Please make a note of it. Password: Re-enter password: % The subject name in the certificate will include:c2851-27.cisco.com % Include the router serial number in the subject name? [yes/no]:no % Include an IP address in the subject name? [no]:no Request certificate from CA? [yes/no]:yes % Certificate request sent to Certificate Authority % The 'show crypto ca certificate IOSCA verbose' command will show the fingerprint. *Jan 13 06:47:19.413:CRYPTO_PKI: Certificate Request Fingerprint MD5:E6DDAB1B 0E30EFE6 54529D8A DA787DBA *Jan 13 06:47:19.413:CRYPTO_PKI: Certificate Request Fingerprint SHA1:3B0F33B 7 57C02A10 3935042B C4B6CD3D 61039251 *Jan 13 06:47:21.021:%PKI-6-CERTRET:Certificate received from Certificate Authority ! Issue the write memory command, which will automatically save the RSA keys to the eToken ! instead of private NVRAM. Router# write memory Building configuration... [OK] *Jan 13 06:47:29.481:%CRYPTO-6-TOKENSTOREKEY:Key c2851-27.cisco.com stored on Cryptographic Token eToken Successfully
The following sample output from the show crypto key mypubkey rsa command displays stored credentials after they are successfully loaded from the USB token. Credentials that are stored on the USB token are in the protected area. When storing the credentials on the USB token, the files are stored in a directory called /keystore. However, the key files are hidden from the command-line interface (CLI).
Router# show crypto key mypubkey rsa % Key pair was generated at:06:37:26 UTC Jan 13 2005 Key name:c2851-27.cisco.com Usage:General Purpose Key Key is not exportable. Key Data: 305C300D 06092A86 4886F70D 01010105 00034B00 30480241 00E3C644 43AA7DDD 732E0F4E 3CA0CDAB 387ABF05 EB8F22F2 2431F1AE 5D51FEE3 FCDEA934 7FBD3603 7C977854 B8E999BF 7FC93021 7F46ABF8 A4BA2ED6 172D3D09 B5020301 0001 % Key pair was generated at:06:37:27 UTC Jan 13 2005 Key name:c2851-27.cisco.com.server Usage:Encryption Key Key is not exportable. Key Data: 307C300D 06092A86 4886F70D 01010105 00036B00 30680261 00DD96AE 4BF912EB 2C261922 4784EF98 2E70E837 774B3778 7F7AEB2D 87F5669B BF5DDFBC F0D521A5 56AB8FDC 9911968E DE347FB0 A514A856 B30EAFF4 D1F453E1 003CFE65 0CCC6DC7 21FBE3AC 2F8DEA16 126754BC 1433DEF9 53266D33 E7338C95 BB020301 0001
Feature Information for Storing PKI Credentials
The following table provides release information about the feature or features described in this module. This table lists only the software release that introduced support for a given feature in a given software release train. Unless noted otherwise, subsequent releases of that software release train also support that feature.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to www.cisco.com/go/cfn. An account on Cisco.com is not required.
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Any Internet Protocol (IP) addresses and phone numbers used in this document are not intended to be actual addresses and phone numbers. Any examples, command display output, network topology diagrams, and other figures included in the document are shown for illustrative purposes only. Any use of actual IP addresses or phone numbers in illustrative content is unintentional and coincidental.
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