ECDSA cipher suites support
ECDSA cipher suites use elliptical curve cryptography (ECC). Because of its smaller size, it is helpful in environments where processing power, storage space, bandwidth, and power consumption are constrained.
The following Citrix ADC appliances now support the elliptical curve digital signature algorithm (ECDSA) cipher group:
- Citrix ADC MPX and SDX appliances with N3 chips
- Citrix ADC MPX 5900/8900/15000/26000
- Citrix ADC SDX 8900/15000
- Citrix ADC VPX appliances
When the ECDHE_ECDSA cipher group is used, the server’s certificate must contain an ECDSA-capable public key.
Note: From release 12.1 build 50.x, you can create an ECDSA key in PKCS#8 format.
Example:
sh ssl cipher ECDSA
1) Cipher Name: TLS1-ECDHE-ECDSA-AES256-SHA Priority : 1
Description: SSLv3 Kx=ECC-DHE Au=ECDSA Enc=AES(256) Mac=SHA1 HexCode=0xc00a
2) Cipher Name: TLS1-ECDHE-ECDSA-AES128-SHA Priority : 2
Description: SSLv3 Kx=ECC-DHE Au=ECDSA Enc=AES(128) Mac=SHA1 HexCode=0xc009
3) Cipher Name: TLS1.2-ECDHE-ECDSA-AES256-SHA384 Priority : 3
Description: TLSv1.2 Kx=ECC-DHE Au=ECDSA Enc=AES(256) Mac=SHA-384 HexCode=0xc024
4) Cipher Name: TLS1.2-ECDHE-ECDSA-AES128-SHA256 Priority : 4
Description: TLSv1.2 Kx=ECC-DHE Au=ECDSA Enc=AES(128) Mac=SHA-256 HexCode=0xc023
5) Cipher Name: TLS1.2-ECDHE-ECDSA-AES256-GCM-SHA384 Priority : 5
Description: TLSv1.2 Kx=ECC-DHE Au=ECDSA Enc=AES-GCM(256) Mac=AEAD HexCode=0xc02c
6) Cipher Name: TLS1.2-ECDHE-ECDSA-AES128-GCM-SHA256 Priority : 6
Description: TLSv1.2 Kx=ECC-DHE Au=ECDSA Enc=AES-GCM(128) Mac=AEAD HexCode=0xc02b
7) Cipher Name: TLS1-ECDHE-ECDSA-DES-CBC3-SHA Priority : 7
Description: SSLv3 Kx=ECC-DHE Au=ECDSA Enc=3DES(168) Mac=SHA1 HexCode=0xc008
8) Cipher Name: TLS1-ECDHE-ECDSA-RC4-SHA Priority : 8
Description: SSLv3 Kx=ECC-DHE Au=ECDSA Enc=RC4(128) Mac=SHA1 HexCode=0xc007
9) Cipher Name: TLS1.2-ECDHE-ECDSA-CHACHA20-POLY1305 Priority : 9
Description: TLSv1.2 Kx=ECC-DHE Au=ECDSA Enc=CHACHA20/POLY1305(256) Mac=AEAD HexCode=0xcca9
Done
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The following table lists the ECDSA ciphers that are supported on the Citrix ADC MPX and SDX appliances with N3 chips, Citrix ADC VPX appliances, MPX 5900/26000, and MPX/SDX 8900/15000 appliances.
| Cipher Name | Priority | Description | Key Exchange Algorithm | Authentication Algorithm | Encryption Algorithm (Key Size) | Message Authentication Code (MAC) Algorithm | HexCode |
|---|---|---|---|---|---|---|---|
| TLS1-ECDHE-ECDSA-AES128-SHA | 1 | SSLv3 | ECC-DHE | ECDSA | AES(128) | SHA1 | 0xc009 |
| TLS1-ECDHE-ECDSA-AES256-SHA | 2 | SSLv3 | ECC-DHE | ECDSA | AES(256) | SHA1 | 0xc00a |
| TLS1.2-ECDHE-ECDSA-AES128-SHA256 | 3 | TLSv1.2 | ECC-DHE | ECDSA | AES(128) | SHA-256 | 0xc023 |
| TLS1.2-ECDHE-ECDSA-AES256-SHA384 | 4 | TLSv1.2 | ECC-DHE | ECDSA | AES(256) | SHA-384 | 0xc024 |
| TLS1.2-ECDHE-ECDSA-AES128-GCM-SHA256 | 5 | TLSv1.2 | ECC-DHE | ECDSA | AES-GCM(128) | SHA-256 | 0xc02b |
| TLS1.2-ECDHE-ECDSA-AES256-GCM-SHA384 | 6 | TLSv1.2 | ECC-DHE | ECDSA | AES-GCM(256) | SHA-384 | 0xc02c |
| TLS1-ECDHE-ECDSA-RC4-SHA | 7 | SSLv3 | ECC-DHE | ECDSA | RC4(128) | SHA1 | 0xc007 |
| TLS1-ECDHE-ECDSA-DES-CBC3-SHA | 8 | SSLv3 | ECC-DHE | ECDSA | 3DES(168) | SHA1 | 0xc008 |
| TLS1.2-ECDHE-ECDSA-CHACHA20-POLY1305 | 9 | TLSv1.2 | ECC-DHE | ECDSA | CHACHA20/POLY1305(256) | AEAD | 0xcca9 |
Important
Use the show ns hardware command to find out if your appliance has N3 chips.
Example:
sh ns hardware
Platform: NSMPX-22000 16*CPU+24*IX+12*E1K+2*E1K+4*CVM N3 2200100
Manufactured on: 8/19/2013
CPU: 2900MHZ
Host Id: 1006665862
Serial no: ENUK6298FT
Encoded serial no: ENUK6298FT
Done
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ECDSA/RSA cipher and certificate selection
You can bind both ECDSA and RSA server certificates at the same time to an SSL virtual server. When both ECDSA and RSA certificates are bound to the virtual server, it automatically selects the appropriate server certificate to present to the client. If the client cipher list includes RSA ciphers, but does not include ECDSA ciphers, the virtual server presents the RSA server certificate. If both ciphers are present in the client’s list, then the server certificate presented depends on the cipher priority set on the virtual server. That is, if RSA has a higher priority, the RSA certificate is presented. If ECDSA has a higher priority, the ECDSA certificate is presented to the client.
Client authentication by using an ECDSA or an RSA certificate
For client authentication, the CA certificate bound to the virtual server can be ECDSA or RSA signed. The appliance supports a mixed certificate chain. For example, the following certificate chain is supported.
Client certificate (ECDSA) <-> CA certificate (RSA) <-> Intermediate certificate (RSA) <-> Root certificate (RSA)
Note
ECDSA certificates with only the following curves are supported:
- prime256v1
- secp384r1
- secp521r1 (VPX only)
- secp224r1 (VPX only)
Create an ECDSA certificate-key pair
You can create an ECDSA certificate-key pair directly on a Citrix ADC appliance by using the CLI or the GUI. Earlier, you could install and bind an ECC certificate-key pair on the appliance, but you had to use OpenSSL to create a certificate-key pair.
Only P_256 and P_384 curves are supported.
Note
This support is available on all platforms except MPX 9700/1050/12500/15500.
To create an ECDSA certificate-key pair by using the CLI:
At the command prompt, type:
create ssl ecdsaKey <keyFile> -curve ( P_256 | P_384 ) [-keyform ( DER | PEM )] [-des | -des3] {-password } [-pkcs8]
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Example:
create ecdsaKey ec_p256.ky -curve P_256 -pkcs8
Done
create ecdsaKey ec_p384.ky -curve P_384
Done
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To create an ECDSA certificate-key pair by using the GUI:
- Navigate to Traffic Management > SSL > SSL Files > Keys and click Create ECDSA Key.
- To create a key in PKCS#8 format, select PKCS8.