Blinded Paths

Blinded paths allow the creator of an invoice to specify the last hops that a payment to their node must take. This path is included in the Lightning Network invoice in encrypted form.

Starting from LND 0.18.3 users have the option to define the last hops of any Lightning Network payment.

Invoices created with the --blind option use a new dummy destination pubkey, and typically contain three alternative paths, each with three hops. Only the first hop of that path is revealed. It is referred to as the “introduction node.” This path is included in the invoice in encrypted form. The payer will only have to construct their route to the introduction node and append the binary blobs from the invoice.

Invoices with blinded paths can be quite long. This may make them impractical for traditional QR codes. The size can be reduced by limiting the number of blinded paths per invoice.

When only a limited number of short paths exist between two nodes, blinded paths may not be payable and the recipient may still be identifiable through other analysis, such as correlating the fees of real channels around the introduction node with those of the blinded path.

Blinded path example

In the example below we generate an invoice with the command lncli addinvoice 100 --blind

lnbc1u1pn0mykwpp5nqz5z6md5z6hss8thmpd2d57cqep7xxqraq9fzcytx7hvv5sg9wqdqqxqyz5vq5jhqqqqphgqqqpf2qf0qqqqqqqqqqzycqqqqqq63h9xqqqqqq4c0utvs26cyazs3jey8twnq9ada2grez3ad0wlmamyq2hwmx4m05psyg7h4fy3uf4rq76zqwgkhrtqmmvvl6pjsp45xttvlsnca93hf7d2ge58a5e40u03776q54z7menaez9ae54exq60ssnnvf8vympsh3cdqxf7elncw9v43944llnfac4vvm3sss8wgen4dkfcp30yfc5sj496ku8pva7d65p0h0hxudhde4sgcrj4ewd4fc23mr5m3lu7esgyke9mgp9ewwlx2kzx8qlqzgyynrmcdxasxe5yukv864dlusf2tpqcksjfnxgsuutxd9r8hxf5mw868vzu870yk9fkxj6ausedug9y6jpf6zkz4qp3vtwa2vu4enay9dguq09z7lv2s6ettz34tlefyrj6us2cffvqg80g7kyzk0r0w24d8sw823k6s3eqydlrgy5ehqy0mq7n56mjlk4z6vvzclu35tzlrmuhywqqjqvm5a4km3t2wxfeesh0kv6qcaq94dwgd5l3ngmkp2qhdu2h6f60pg75d6w9ltc5jgqqqqfwcqqqqa5q2lqqqqqqqqqqzycqqqqqqz46j5qqqqqqafqerczge4wuehqtup2mldh80yy28q2w84a30yq2m4g2rfkdnvgvps8s2hj3kvrnfhdwffudsqdej9ltjfpvd36s2kksxmsp8qrd9a5jxdgvh88j9hhc04z9ac8knp4u57qvl6sn4wvuqudld6eutfxgf92ham2as9dze6d6n83stmdpege8n5lud7gv5708qh4hjuv90f3vfdgfu53slngqnnllv8t37y2aq7r6syk7r6wh3aestn9f6ht6ywjsdv2fn36qqddaps334233a6yems4539lfum5muxdsgzy642gjfwcvzrw54ge3zsukuesxx0w2pqsn0lqs6nwqdy3es7z5xcpqs8q5xep555dd7psczpsday7mqrmjyyhlgzksnd9twm9h9ymru4tna3aw72zy33e4y4zqdlpg26n48y85h2xwn75yxpvjvalg5ttwtux9uz4jl576dc0keh9qvkduwp0yfammhddvdmch6vrq3mzpgppzr9hw240w506xg6dsjdw5d0psuy4r9ggawq5jgqqqqfwgqqqpk7q2lqqqqqqqqqqzycqqqqqq63h9xqqqqqqmkf0zees7hx5mmtqcand60ek9qw5c26wj7ludrntwwj2tadc87aypsx00wn34q4lzqllv0yltgaunq70j7rsv7t8r0nwmq07cyc82f02qfgwem8rhqgrncpc5qxn6rw5kk2pn8kzu5r93cxs9yneztc04pygr2mfvezv93gxa3wz3s52trrsahjkdac8rrtujutt9hm37d2k55695dyv4u5qcmqy3cqgqj4vt8jtjz4l7cee0njfdcqm64adaetp8x4yl3qu5h4apmp25p3xq3z3nmx7wc4jc5er496tzaer6v8frds38h842uku62qeu80j2uf4duptgu65fafpdp2f5vfn85fj5l7ejhvfde2qhgagrrtcx7yggr4m3hnrpz2hewfqqw38qns03m7g9h08gg2c8pp8k9q6kz8ruu39qyx2vx6n7lq9s95aqpq4f28xf5w4ajk44enwznqwr6rum8daznju5dpvfne6xes9qamgv3v9l060g2mt7jhe42em04zvq00mccgrqqv2h8kg0n9p4yqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqqpq9qgqqf98d722zvu5jg55qw8g7p6h07svytvg88rrkt2nj430fhuddc58xcmfrjal4h7jddwcn9m78k60d3tw8fywqwga7weh58ay2tc8recqqwpcuj

Decoding this invoice reveals the three alternative paths, their introduction nodes and respective fees.

{
	"destination":  "021b551120ff8a4503a8732b6e44c4baf23abf6d6c2911caa8bfb114b180da41e6",
	"payment_hash":  "9805416b6da0b57840ebbec2d5369ec0321f18c01f40548b0459bd763290415c",
	"num_satoshis":  "100",
	"timestamp":  "1727894222",
	"expiry":  "86400",
	"description":  "",
	"description_hash":  "",
	"fallback_addr":  "",
	"cltv_expiry":  "18",
	"route_hints":  [],
	"payment_addr":  "",
	"num_msat":  "100000",
	"features":  {
    	"8":  {
        	"name":  "tlv-onion",
        	"is_required":  true,
        	"is_known":  true
    	},
    	"15":  {
        	"name":  "payment-addr",
        	"is_required":  false,
        	"is_known":  true
    	},
    	"17":  {
        	"name":  "multi-path-payments",
        	"is_required":  false,
        	"is_known":  true
    	},
    	"25":  {
        	"name":  "route-blinding",
        	"is_required":  false,
        	"is_known":  true
    	},
    	"262":  {
        	"name":  "bolt-11-blinded-paths",
        	"is_required":  true,
        	"is_known":  true
    	}
	},
	"blinded_paths":  [
    	{
        	"blinded_path":  {
            	"introduction_node":  "0223d7aa491e26a307b4203916b8d60ded8cfe832806b432d6cfc278e96374f9aa",
            	"blinding_point":  "02b87f16c82b58274508cb243add3017adea903c8a3d6bddfdf76402aeed9abb7d",
            	"blinded_hops":  [
                	{
                    	"blinded_node":  "0223d7aa491e26a307b4203916b8d60ded8cfe832806b432d6cfc278e96374f9aa",
                    	"encrypted_data":  "687ed3357f1f1f7b40a545ede67dc88bdcd2b93034f84273624ec26c30bc70d0193ecfe7871595896b5ffe69ee2ac66e30840ee466756d9380c5e44e290954bab70e1677cdd5"
                	},
                	{
                    	"blinded_node":  "02fbbee6e36edcd608c0e55cb9b54e151d8e9b8ff9ecc104b64bb404b973be6558",
                    	"encrypted_data":  "383e01208498f7869bb036684e5987d55bfe412a58418b424999910e716669467b9934db8fa3b05c3f9e4b153634b5de432de20a4d4829d0ac2a803162ddd53395ccfa42b51c"
                	},
                	{
                    	"blinded_node":  "03ca2f7d8a86b2b58a355ff2920e5ae41584a58041de8f5882b3c6f72aad3c1c75",
                    	"encrypted_data":  "da84720237e341299b808fd83d3a6b72fdaa2d3182c7f91a2c5f1ef97238009019ba76b6dc56a71939cc2efb3340c7405ab5c86d3f19a3760a8176f157d274f0a3d46e9c5faf"
                	}
            	]
        	},
        	"base_fee_msat":  "221",
        	"proportional_fee_rate":  661,
        	"total_cltv_delta":  303,
        	"htlc_min_msat":  "1100",
        	"htlc_max_msat":  "7128000000",
        	"features":  []
    	},
    	{
        	"blinded_path":  {
            	"introduction_node":  "03c157946cc1cd376b929e36006e645fae490b1b1d4156b40db804e01b4bda48cd",
            	"blinding_point":  "03a906478123357733702f8156fedb9de4228e0538f5ec5e402b7542869b366c43",
            	"blinded_hops":  [
                	{
                    	"blinded_node":  "03c157946cc1cd376b929e36006e645fae490b1b1d4156b40db804e01b4bda48cd",
                    	"encrypted_data":  "2e73c8b7be1f5117b83da61af29e033fa84eae6701c6fdbacf1693212555fbb5760568b3a6ea678c17b68728c9e74ff1be4329e79c17ade5c615e98b12d427948c3f34"
                	},
                	{
                    	"blinded_node":  "0273ffd875c7c45741e1ea04b787a75e3dcc1732a7575e88e941ac52671d000d6f",
                    	"encrypted_data":  "08c6aa8c7ba26770ad225fa79ba6f866c10226aaa4492ec3043752a8cc450e5b99818cf7282084dff04353701a48e61e150d808207050d90d2946b7c186041837a4f6c"
                	},
                	{
                    	"blinded_node":  "03dc884bfd02b426d2addb2dca4d8f955cfb1ebbca11231cd495101bf0a15a9d4e",
                    	"encrypted_data":  "d2ea33a7ea10c16499dfa28b5b97c31782acbf4f69b87db37281966f1c17913ddeeed6b1bbc5f4c1823b1050108865bb9557ba8fd191a6c24d751af0c384a8ca8475c0"
                	}
            	]
        	},
        	"base_fee_msat":  "1211",
        	"proportional_fee_rate":  474,
        	"total_cltv_delta":  351,
        	"htlc_min_msat":  "1100",
        	"htlc_max_msat":  "720000000",
        	"features":  []
    	},
    	{
        	"blinded_path":  {
            	"introduction_node":  "033dee9c6a0afc40ffd8f27d68ef260f3e5e1c19e59c6f9bb607fb04c1d497a809",
            	"blinding_point":  "03764bc59cc3d73537b5831d9b74fcd8a07530ad3a5eff1a39adce9297d6e0fee9",
            	"blinded_hops":  [
                	{
                    	"blinded_node":  "033dee9c6a0afc40ffd8f27d68ef260f3e5e1c19e59c6f9bb607fb04c1d497a809",
                    	"encrypted_data":  "b3b38ee040e780e28034f43752d650667b0b9419638340a49e44bc3ea12206ada599130b141bb170a30a29631c3b7959bdc1c635f25c5acb7dc7cd55a94d168d232bca"
                	},
                	{
                    	"blinded_node":  "031b0123802012ab16792e42affd8ce5f3925b806f55eb7b9584e6a93f107297af",
                    	"encrypted_data":  "b0aa81898111467b379d8acb14c8ea5d2c5dc8f4c3a46d844f73d55cb734a067877c95c4d5bc0ad1cd513d485a15268c4ccf44ca9ff6657625b9502e8ea0635e0de221"
                	},
                	{
                    	"blinded_node":  "03aee3798c2255f2e4800e89c1383e3bf20b779d08560e109ec506ac238f9c8940",
                    	"encrypted_data":  "2986d4fdf01605a74010552a39934757b2b56b99b8530387a1f3676f4539728d0b133ce8d98141dda191617efd3d0adafd2be6aacedf51300f7ef1840c0062ae7b21f3"
                	}
            	]
        	},
        	"base_fee_msat":  "1209",
        	"proportional_fee_rate":  879,
        	"total_cltv_delta":  351,
        	"htlc_min_msat":  "1100",
        	"htlc_max_msat":  "7128000000",
        	"features":  []
    	}
	]
}

Additionally, it is possible to specify the number of real hops used in the blinded paths (--min_real_blinded_hops), the number of hops to be used for each blinded path (--num_blinded_hops) and the maximum number of blinded paths (--max_blinded_paths).

It is also possible to specifically exclude nodes from blinded paths with the --blinded_path_omit_node flag.