diff --git a/rust/Cargo.lock b/rust/Cargo.lock
index 54e3b1c..daa4185 100644
--- a/rust/Cargo.lock
+++ b/rust/Cargo.lock
@@ -41,6 +41,11 @@ name = "cfg-if"
 version = "0.1.6"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "cfg-if"
+version = "1.0.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "clap"
 version = "2.33.3"
@@ -78,6 +83,16 @@ dependencies = [
  "smallvec 0.6.7 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "getrandom"
+version = "0.1.16"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "cfg-if 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.76 (registry+https://github.com/rust-lang/crates.io-index)",
+ "wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "heck"
 version = "0.3.1"
@@ -131,6 +146,7 @@ dependencies = [
  "autocfg 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-integer 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
 [[package]]
@@ -150,6 +166,11 @@ dependencies = [
  "autocfg 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "ppv-lite86"
+version = "0.2.10"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "proc-macro-error"
 version = "1.0.4"
@@ -188,6 +209,43 @@ dependencies = [
  "proc-macro2 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)",
 ]
 
+[[package]]
+name = "rand"
+version = "0.7.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getrandom 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
+ "libc 0.2.76 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rand_chacha"
+version = "0.2.2"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "ppv-lite86 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rand_core"
+version = "0.5.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "getrandom 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
+[[package]]
+name = "rand_hc"
+version = "0.2.0"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+dependencies = [
+ "rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)",
+]
+
 [[package]]
 name = "regex"
 version = "1.1.0"
@@ -361,6 +419,11 @@ name = "void"
 version = "1.0.2"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 
+[[package]]
+name = "wasi"
+version = "0.9.0+wasi-snapshot-preview1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+
 [[package]]
 name = "winapi"
 version = "0.3.9"
@@ -390,12 +453,13 @@ dependencies = [
 
 [[package]]
 name = "zkinterface"
-version = "1.3.2"
+version = "1.3.3"
 dependencies = [
  "colored 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "flatbuffers 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-bigint 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "num-traits 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)",
+ "rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)",
  "regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde 1.0.111 (registry+https://github.com/rust-lang/crates.io-index)",
  "serde_json 1.0.53 (registry+https://github.com/rust-lang/crates.io-index)",
@@ -410,10 +474,12 @@ dependencies = [
 "checksum autocfg 1.0.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cdb031dd78e28731d87d56cc8ffef4a8f36ca26c38fe2de700543e627f8a464a"
 "checksum bitflags 1.2.1 (registry+https://github.com/rust-lang/crates.io-index)" = "cf1de2fe8c75bc145a2f577add951f8134889b4795d47466a54a5c846d691693"
 "checksum cfg-if 0.1.6 (registry+https://github.com/rust-lang/crates.io-index)" = "082bb9b28e00d3c9d39cc03e64ce4cea0f1bb9b3fde493f0cbc008472d22bdf4"
+"checksum cfg-if 1.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "baf1de4339761588bc0619e3cbc0120ee582ebb74b53b4efbf79117bd2da40fd"
 "checksum clap 2.33.3 (registry+https://github.com/rust-lang/crates.io-index)" = "37e58ac78573c40708d45522f0d80fa2f01cc4f9b4e2bf749807255454312002"
 "checksum colored 2.0.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b3616f750b84d8f0de8a58bda93e08e2a81ad3f523089b05f1dffecab48c6cbd"
 "checksum dtoa 0.4.6 (registry+https://github.com/rust-lang/crates.io-index)" = "134951f4028bdadb9b84baf4232681efbf277da25144b9b0ad65df75946c422b"
 "checksum flatbuffers 0.5.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ea0c34f669be9911826facafe996adfda978aeee67285a13556869e2d8b8331f"
+"checksum getrandom 0.1.16 (registry+https://github.com/rust-lang/crates.io-index)" = "8fc3cb4d91f53b50155bdcfd23f6a4c39ae1969c2ae85982b135750cccaf5fce"
 "checksum heck 0.3.1 (registry+https://github.com/rust-lang/crates.io-index)" = "20564e78d53d2bb135c343b3f47714a56af2061f1c928fdb541dc7b9fdd94205"
 "checksum hermit-abi 0.1.15 (registry+https://github.com/rust-lang/crates.io-index)" = "3deed196b6e7f9e44a2ae8d94225d80302d81208b1bb673fd21fe634645c85a9"
 "checksum itoa 0.4.5 (registry+https://github.com/rust-lang/crates.io-index)" = "b8b7a7c0c47db5545ed3fef7468ee7bb5b74691498139e4b3f6a20685dc6dd8e"
@@ -424,10 +490,15 @@ dependencies = [
 "checksum num-bigint 0.3.0 (registry+https://github.com/rust-lang/crates.io-index)" = "b7f3fc75e3697059fb1bc465e3d8cca6cf92f56854f201158b3f9c77d5a3cfa0"
 "checksum num-integer 0.1.43 (registry+https://github.com/rust-lang/crates.io-index)" = "8d59457e662d541ba17869cf51cf177c0b5f0cbf476c66bdc90bf1edac4f875b"
 "checksum num-traits 0.2.12 (registry+https://github.com/rust-lang/crates.io-index)" = "ac267bcc07f48ee5f8935ab0d24f316fb722d7a1292e2913f0cc196b29ffd611"
+"checksum ppv-lite86 0.2.10 (registry+https://github.com/rust-lang/crates.io-index)" = "ac74c624d6b2d21f425f752262f42188365d7b8ff1aff74c82e45136510a4857"
 "checksum proc-macro-error 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "da25490ff9892aab3fcf7c36f08cfb902dd3e71ca0f9f9517bea02a73a5ce38c"
 "checksum proc-macro-error-attr 1.0.4 (registry+https://github.com/rust-lang/crates.io-index)" = "a1be40180e52ecc98ad80b184934baf3d0d29f979574e439af5a55274b35f869"
 "checksum proc-macro2 1.0.18 (registry+https://github.com/rust-lang/crates.io-index)" = "beae6331a816b1f65d04c45b078fd8e6c93e8071771f41b8163255bbd8d7c8fa"
 "checksum quote 1.0.6 (registry+https://github.com/rust-lang/crates.io-index)" = "54a21852a652ad6f610c9510194f398ff6f8692e334fd1145fed931f7fbe44ea"
+"checksum rand 0.7.3 (registry+https://github.com/rust-lang/crates.io-index)" = "6a6b1679d49b24bbfe0c803429aa1874472f50d9b363131f0e89fc356b544d03"
+"checksum rand_chacha 0.2.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f4c8ed856279c9737206bf725bf36935d8666ead7aa69b52be55af369d193402"
+"checksum rand_core 0.5.1 (registry+https://github.com/rust-lang/crates.io-index)" = "90bde5296fc891b0cef12a6d03ddccc162ce7b2aff54160af9338f8d40df6d19"
+"checksum rand_hc 0.2.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ca3129af7b92a17112d59ad498c6f81eaf463253766b90396d39ea7a39d6613c"
 "checksum regex 1.1.0 (registry+https://github.com/rust-lang/crates.io-index)" = "37e7cbbd370869ce2e8dff25c7018702d10b21a20ef7135316f8daecd6c25b7f"
 "checksum regex-syntax 0.6.5 (registry+https://github.com/rust-lang/crates.io-index)" = "8c2f35eedad5295fdf00a63d7d4b238135723f92b434ec06774dad15c7ab0861"
 "checksum ryu 1.0.5 (registry+https://github.com/rust-lang/crates.io-index)" = "71d301d4193d031abdd79ff7e3dd721168a9572ef3fe51a1517aba235bd8f86e"
@@ -451,6 +522,7 @@ dependencies = [
 "checksum vec_map 0.8.2 (registry+https://github.com/rust-lang/crates.io-index)" = "f1bddf1187be692e79c5ffeab891132dfb0f236ed36a43c7ed39f1165ee20191"
 "checksum version_check 0.9.2 (registry+https://github.com/rust-lang/crates.io-index)" = "b5a972e5669d67ba988ce3dc826706fb0a8b01471c088cb0b6110b805cc36aed"
 "checksum void 1.0.2 (registry+https://github.com/rust-lang/crates.io-index)" = "6a02e4885ed3bc0f2de90ea6dd45ebcbb66dacffe03547fadbb0eeae2770887d"
+"checksum wasi 0.9.0+wasi-snapshot-preview1 (registry+https://github.com/rust-lang/crates.io-index)" = "cccddf32554fecc6acb585f82a32a72e28b48f8c4c1883ddfeeeaa96f7d8e519"
 "checksum winapi 0.3.9 (registry+https://github.com/rust-lang/crates.io-index)" = "5c839a674fcd7a98952e593242ea400abe93992746761e38641405d28b00f419"
 "checksum winapi-i686-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "ac3b87c63620426dd9b991e5ce0329eff545bccbbb34f3be09ff6fb6ab51b7b6"
 "checksum winapi-x86_64-pc-windows-gnu 0.4.0 (registry+https://github.com/rust-lang/crates.io-index)" = "712e227841d057c1ee1cd2fb22fa7e5a5461ae8e48fa2ca79ec42cfc1931183f"