Cipher names (ipsec) – Server Fault

I’ve got this in my syslog

 470  Nov 22 11:32:23 mini31 ipsec(8820): 13(IKE) 192.168.1.7 is initiating a Main Mode IKE_SA
   471  Nov 22 11:32:23 mini31 ipsec(8820): 13(CFG) received proposals: IKE:AES_CBC_256/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_256/HMAC_MD5_96/PRF_HMAC_MD5/MODP_1024, IKE:AES_CBC_128/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:AES_CBC_128/HMAC_MD5_96/PRF_HMAC_MD5/MODP_1024, IKE:3DES_CBC/HMAC_SHA1_96/PRF_HMAC_SHA1/MODP_1024, IKE:3DES_CBC/HMAC_MD5_96/PRF_HMAC_MD5/MODP_1024
   472  Nov 22 11:32:23 mini31 ipsec(8820): 13(CFG) configured proposals: IKE:AES_CBC_128/AES_CBC_192/AES_CBC_256/CAMELLIA_CBC_128/CAMELLIA_CBC_192/CAMELLIA_CBC_256/3DES_CBC/HMAC_SHA2_256_128/HMAC_SHA2_384_192/HMAC_SHA2_512_256/HMAC_SHA1_96/AES_XCBC_96/PRF_HMAC_SHA2_256/PRF_HMAC_SHA2_384/PRF_HMAC_SHA2_512/PRF_AES128_XCBC/PRF_HMAC_SHA1/ECP_256/ECP_384/ECP_521/ECP_256_BP/ECP_384_BP/ECP_512_BP/CURVE_25519/CURVE_448/MODP_3072/MODP_4096/MODP_6144/MODP_8192/MODP_2048, IKE:AES_GCM_16_128/AES_GCM_16_192/AES_GCM_16_256/AES_GCM_12_128/AES_GCM_12_192/AES_GCM_12_256/AES_GCM_8_128/AES_GCM_8_192/AES_GCM_8_256/PRF_HMAC_SHA2_256/PRF_HMAC_SHA2_384/PRF_HMAC_SHA2_512/PRF_AES128_XCBC/PRF_HMAC_SHA1/ECP_256/ECP_384/ECP_521/ECP_256_BP/ECP_384_BP/ECP_512_BP/CURVE_25519/CURVE_448/MODP_3072/MODP_4096/MODP_6144/MODP_8192/MODP_2048
   473  Nov 22 11:32:23 mini31 ipsec(8820): 13(IKE) no proposal found

But clearly — and very unhelpfully — the format of the cypher names is different to that used in ipsec.conf

ike=aes-sha,3des-sha,aes128-aes256-sha1-modp3072-modp2048,3des-sha1-md5-modp1024,aes128-sha1-modp1536

The documentation for ipsec.conf (https://wiki.strongswan.org/projects/strongswan/wiki/ConnSection) explains that the format is:

encryption-integrity(-prf)-dhgroup

How do I translate the cipher names in the syslog into this format?

My guess would be that it’s something to do with chopping out the CBC/HMAC/PRF and sometimes the number and downcasing what’s left and replacing slashes with hyphens — which makes no sense.