SSH Cipher Support

This topic details SSH cipher suite encryption, key exchange, and MAC algorithms.

Enable FIPS in Secret Server On-Premises to ensure all algorithms are FIPS-certified. FIPS 140-2 compliance is built-in to Secret Server Cloud and is always on.
SecureBlackbox enables all available SSH encryption, key exchange, and MAC algorithms by default.

This information applies to the following as of Secret Server On-Premises 11.2.X (June 2022).

  • SSH Server: Used by SSH proxy
  • SSH Client: Used by SSH proxy, RPC, heartbeat, discovery, and script runners.
  • Local port forwarding: Used by SSH proxy Jumpbox routes)

Secret Server On-Premises with FIPS Enabled

Default Encryption Algorithms, FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
aes256-cbc SSH_EA_AES256 2147483646
aes192-cbc SSH_EA_AES192 2147483645
aes128-cbc SSH_EA_AES128 2147483644
3des-cbc SSH_EA_3DES 2147483643

Default Key Exchange Algorithms, FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
rsa1024-sha1 SSH_KEX_RSA1024_SHA1 2147483646
rsa2048-sha256 SSH_KEX_RSA2048_SHA256 2147483645

Default MAC Algorithms, FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
hmac-sha2-512 SSH_MA_HMAC_SHA2_512 2147483646
hmac-sha2-256 SSH_MA_HMAC_SHA2_256 2147483645
hmac-sha256@ssh.com SSH_MA_HMAC_SHA256 2147483644
hmac-sha256-96@ssh.com SSH_MA_HMAC_SHA256_96 2147483643
hmac-sha1 SSH_MA_HMAC_SHA1 2147483642

Default Public-Key Algorithms, FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
x509v3-sign-rsa SSH_PK_X509_SIGN_RSA 2147483646
x509v3-sign-dss SSH_PK_X509_SIGN_DSS 2147483645
spki-sign-rsa SSH_PK_SPKI_SIGN_RSA 2147483644
spki-sign-dss SSH_PK_SPKI_SIGN_DSS 2147483643
pgp-sign-rsa SSH_PK_PGP_SIGN_RSA 2147483642
pgp-sign-dss SSH_PK_PGP_SIGN_DSS 2147483641
x509v3-ssh-rsa SSH_PK_X509_SSH_RSA 2147483640
x509v3-ssh-dss SSH_PK_X509_SSH_DSS 2147483639
x509v3-rsa2048-sha256 SH_PK_X509_RSA2048_SHA256 2147483638
rsa-sha2-256 SSH_PK_RSA_SHA256 2147483637
rsa-sha2-512 SSH_PK_RSA_SHA512 2147483636
ssh-dss SSH_PK_DSS 2147483635
ssh-rsa SSH_PK_RSA 2147483634

Secret Server with FIPS Disabled

Default Encryption Algorithms, Non-FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
aes256-gcm@openssh.com SSH_EA_AES256_GCM_OPENSSH 2147483646
aes128-gcm@openssh.com SSH_EA_AES128_GCM_OPENSSH 2147483645
aes256-gcm SSH_EA_AES256_GCM 2147483644
aes128-gcm SSH_EA_AES128_GCM 2147483643
aes256-ctr SSH_EA_AES256_CTR 2147483642
aes192-ctr SSH_EA_AES192_CTR 2147483641
aes128-ctr SSH_EA_AES128_CTR 2147483640
aes256-cbc SSH_EA_AES256 2147483639
aes192-cbc SSH_EA_AES192 2147483638
aes128-cbc SSH_EA_AES128 2147483637
3des-cbc SSH_EA_3DES 2147483636
twofish256-cbc SSH_EA_TWOFISH256 36
twofish192-cbc SSH_EA_TWOFISH192 35
twofish128-cbc SSH_EA_TWOFISH128 34
serpent256-cbc SSH_EA_SERPENT256 33
serpent192-cbc SSH_EA_SERPENT192 32
serpent128-cbc SSH_EA_SERPENT128 31
blowfish-cbc SSH_EA_BLOWFISH 30
twofish128-ctr SSH_EA_TWOFISH128_CTR 29
twofish192-ctr SSH_EA_TWOFISH192_CTR 28
twofish256-ctr SSH_EA_TWOFISH256_CTR 27
serpent128-ctr SSH_EA_SERPENT128_CTR 26
serpent192-ctr SSH_EA_SERPENT192_CTR 25
serpent256-ctr SSH_EA_SERPENT256_CTR 24
blowfish-ctr SSH_EA_BLOWFISH_CTR 23
idea-ctr SSH_EA_IDEA_CTR 22
cast128-ctr SSH_EA_CAST128_CTR 21
arcfour128 SSH_EA_ARCFOUR128 20
arcfour256 SSH_EA_ARCFOUR256 19
cast128-cbc SSH_EA_CAST128 18
3des-ctr SSH_EA_3DES_CTR 16
chacha20-poly1305 SSH_EA_CHACHA20 15
arcfour SSH_EA_ARCFOUR 14
idea-cbc SSH_EA_IDEA 13
chacha20-poly1305@openssh.com SSH_EA_CHACHA20_OPENSSH 12
des-cbc SSH_EA_DES 11
none SSH_EA_NONE 10

Default Key Exchange Algorithms, Non-FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
curve25519-sha256@libssh.org SSH_KEX_CURVE25519 2147483646
diffie-hellman-group-exchange-sha256 SSH_KEX_DH_GROUP_EXCHANGE256 2147483645
diffie-hellman-group14-sha1 SSH_KEX_DH_GROUP_14 2147483644
diffie-hellman-group1-sha1 SSH_KEX_DH_GROUP 2147483643
diffie-hellman-group-exchange-sha1 SSH_KEX_DH_GROUP_EXCHANGE 2147483642
diffie-hellman-group14-sha256 SSH_KEX_DH_GROUP_14_SHA256 2147483641
ecdh-sha2-nistp521 SSH_KEX_ECDH_NIST_P521 2147483640
ecdh-sha2-nistp384 SSH_KEX_ECDH_NIST_P384 2147483639
ecdh-sha2-nistp256 SSH_KEX_ECDH_NIST_P256 2147483638
rsa1024-sha1 SSH_KEX_RSA1024_SHA1 2147483637
rsa2048-sha256 SSH_KEX_RSA2048_SHA256 2147483636

Default MAC Algorithms, Non-FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
chacha20-poly1305@openssh.com SSH_MA_POLY1305 2147483646
aes256-gcm SSH_MA_AES256_GCM 2147483645
aes128-gcm SSH_MA_AES128_GCM 2147483644
hmac-sha2-512 SSH_MA_HMAC_SHA2_512 2147483643
hmac-sha2-256 SSH_MA_HMAC_SHA2_256 2147483642
hmac-sha256@ssh.com SSH_MA_HMAC_SHA256 2147483641
hmac-sha256-96@ssh.com SSH_MA_HMAC_SHA256_96 2147483640
hmac-sha1 SSH_MA_HMAC_SHA1 2147483639
umac-128@openssh.com SSH_MA_UMAC128 2147483638
umac-96@openssh.com SSH_MA_UMAC96 2147483637
umac-64@openssh.com SSH_MA_UMAC64 2147483636
umac-32@openssh.com SSH_MA_UMAC32 2147483635
hmac-sha2-512-etm@openssh.com SSH_MA_HMAC_SHA2_512_ETM 28
hmac-sha2-256-etm@openssh.com SSH_MA_HMAC_SHA2_256_ETM 27
hmac-sha256-96@ssh.com SSH_MA_HMAC_SHA256_96 24
hmac-ripemd160 SSH_MA_HMAC_RIPEMD160 23
hmac-ripemd SSH_MA_HMAC_RIPEMD 22
hmac-ripemd160@openssh.com SSH_MA_HMAC_RIPEMD_OPENSSH 21
hmac-sha1-96 SSH_MA_HMAC_SHA1_96 15
hmac-md5 SSH_MA_HMAC_MD5 13
hmac-md5-96 SSH_MA_HMAC_MD5_96 12
none SSH_MA_NONE 10

Default Public-Key Algorithms, Non-FIPS

The algorithm with highest priority is chosen first, if unsuccessful, the next highest is attempted. The table is ordered by priority.
SSH Cipher Secure Blackbox Encryption Algorithm Priority
x509v3-sign-rsa SSH_PK_X509_SIGN_RSA 2147483646
x509v3-sign-dss SSH_PK_X509_SIGN_DSS 2147483645
spki-sign-rsa SSH_PK_SPKI_SIGN_RSA 2147483644
spki-sign-dss SSH_PK_SPKI_SIGN_DSS 2147483643
pgp-sign-rsa SSH_PK_PGP_SIGN_RSA 2147483642
pgp-sign-dss SSH_PK_PGP_SIGN_DSS 2147483641
ecdsa-sha2-nistp256 SSH_PK_ECDSA_NIST_P256 2147483640
ecdsa-sha2-nistp384 SSH_PK_ECDSA_NIST_P384 2147483639
ecdsa-sha2-nistp521 SSH_PK_ECDSA_NIST_P521 2147483638
ecdsa-sha2-nistk163 SSH_PK_ECDSA_NIST_K163 2147483637
ecdsa-sha2-nistp192 SSH_PK_ECDSA_NIST_P192 2147483636
ecdsa-sha2-nistp224 SSH_PK_ECDSA_NIST_P224 2147483635
ecdsa-sha2-nistk233 SSH_PK_ECDSA_NIST_K233 2147483634
ecdsa-sha2-nistb233 SSH_PK_ECDSA_NIST_B233 2147483633
ecdsa-sha2-nistk283 SSH_PK_ECDSA_NIST_K283 2147483632
ecdsa-sha2-nistk409 SSH_PK_ECDSA_NIST_K409 2147483631
ecdsa-sha2-nistb409 SSH_PK_ECDSA_NIST_B409 2147483630
ecdsa-sha2-nistt571 SSH_PK_ECDSA_NIST_K571 2147483629
ecdsa-sha2-curve25519 SSH_PK_ECDSA_CURVE25519 2147483628
x509v3-ssh-rsa SSH_PK_X509_SSH_RSA 2147483627
x509v3-ssh-dss SSH_PK_X509_SSH_DSS 2147483626
x509v3-rsa2048-sha256 SSH_PK_X509_RSA2048_SHA256 2147483625
x509v3-ecdsa-sha2-nistp256 SSH_PK_X509_ECDSA_SHA2_NIST_P256 2147483624
x509v3-ecdsa-sha2-nistp384 SSH_PK_X509_ECDSA_SHA2_NIST_P384 2147483623
x509v3-ecdsa-sha2-nistp521 SSH_PK_X509_ECDSA_SHA2_NIST_P521 2147483622
x509v3-ecdsa-sha2-nistk163 SSH_PK_X509_ECDSA_SHA2_NIST_K163 2147483621
x509v3-ecdsa-sha2-nistp192 SSH_PK_X509_ECDSA_SHA2_NIST_P192 2147483620
x509v3-ecdsa-sha2-nistp224 SSH_PK_X509_ECDSA_SHA2_NIST_P224 2147483619
x509v3-ecdsa-sha2-nistk233 SSH_PK_X509_ECDSA_SHA2_NIST_K233 2147483618
x509v3-ecdsa-sha2-nistb233 SSH_PK_X509_ECDSA_SHA2_NIST_B233 2147483617
x509v3-ecdsa-sha2-nistk283 SSH_PK_X509_ECDSA_SHA2_NIST_K283 2147483616
x509v3-ecdsa-sha2-nistk409 SSH_PK_X509_ECDSA_SHA2_NIST_K409 2147483615
x509v3-ecdsa-sha2-nistb409 SSH_PK_X509_ECDSA_SHA2_NIST_B409 2147483614
x509v3-ecdsa-sha2-nistt571 SSH_PK_X509_ECDSA_SHA2_NIST_K571 2147483613
x509v3-ecdsa-sha2-curve25519 SSH_PK_X509_ECDSA_SHA2_CURVE25519 2147483612
ssh-ed25519 SSH_PK_ED25519 2147483611
ssh-ed448 SSH_PK_ED448 2147483610
rsa-sha2-256 SSH_PK_RSA_SHA256 2147483609
rsa-sha2-512 SSH_PK_RSA_SHA512 2147483608
ssh-dss SSH_PK_DSS 2147483607
SSH_PK_RSA SSH_PK_RSA 2147483606