Use EIP-55 for string addresses.

go.mod

@@ -8,13 +8,14 @@ require (
 	github.com/rs/zerolog v1.29.0
 	github.com/stretchr/testify v1.8.2
 	github.com/ybbus/jsonrpc/v2 v2.1.7
+	golang.org/x/crypto v0.15.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/mattn/go-colorable v0.1.12 // indirect
 	github.com/mattn/go-isatty v0.0.14 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6 // indirect
+	golang.org/x/sys v0.14.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -31,15 +31,18 @@ github.com/stretchr/testify v1.8.2 h1:+h33VjcLVPDHtOdpUCuF+7gSuG3yGIftsP1YvFihtJ
 github.com/stretchr/testify v1.8.2/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 github.com/ybbus/jsonrpc/v2 v2.1.7 h1:QjoXuZhkXZ3oLBkrONBe2avzFkYeYLorpeA+d8175XQ=
 github.com/ybbus/jsonrpc/v2 v2.1.7/go.mod h1:rIuG1+ORoiqocf9xs/v+ecaAVeo3zcZHQgInyKFMeg0=
-golang.org/x/net v0.0.0-20180906233101-161cd47e91fd h1:nTDtHvHSdCn1m6ITfMRqtOd/9+7a3s8RBNOZ3eYZzJA=
+golang.org/x/crypto v0.15.0 h1:frVn1TEaCEaZcn3Tmd7Y2b5KKPaZ+I32Q2OA3kYp5TA=
+golang.org/x/crypto v0.15.0/go.mod h1:4ChreQoLWfG3xLDer1WdlH5NdlQ3+mwnQq1YTKY+72g=
 golang.org/x/net v0.0.0-20180906233101-161cd47e91fd/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.10.0 h1:X2//UzNDwYmtCLn7To6G58Wr6f5ahEAQgKNzv9Y951M=
 golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sys v0.0.0-20180909124046-d0be0721c37e/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
 golang.org/x/sys v0.0.0-20210630005230-0f9fa26af87c/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6 h1:foEbQz/B0Oz6YIqu/69kfXPYeFQAuuMYFkjaqXzl5Wo=
 golang.org/x/sys v0.0.0-20210927094055-39ccf1dd6fa6/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
-golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/sys v0.14.0 h1:Vz7Qs629MkJkGyHxUlRHizWJRG2j8fbQKjELVSNhy7Q=
+golang.org/x/sys v0.14.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/text v0.14.0 h1:ScX5w1eTa3QqT8oi6+ziP7dTV1S2+ALU0bI+0zXKWiQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/fsnotify.v1 v1.4.7/go.mod h1:Tz8NjZHkW78fSQdbUxIjBTcgA1z1m8ZHf0WmKUhAMys=

jsonrpc/parameters.go

@@ -29,7 +29,7 @@ type parameters struct {
 
 // Parameter is the interface for service parameters.
 type Parameter interface {
-	apply(*parameters)
+	apply(p *parameters)
 }
 
 type parameterFunc func(*parameters)

types/primitives.go

@@ -19,14 +19,33 @@ import (
 	"fmt"
 
 	"github.com/pkg/errors"
+	"golang.org/x/crypto/sha3"
 )
 
 // Address is a 20-byte execution layer address.
 type Address [20]byte
 
-// String returns the string representation of the address.
+// String returns the EIP-55 string representation of the address.
 func (a Address) String() string {
-	return fmt.Sprintf("%#x", a)
+	bytes := []byte(hex.EncodeToString(a[:]))
+
+	keccak := sha3.NewLegacyKeccak256()
+	keccak.Write(bytes)
+	hash := keccak.Sum(nil)
+
+	for i := 0; i < len(bytes); i++ {
+		hashByte := hash[i/2]
+		if i%2 == 0 {
+			hashByte >>= 4
+		} else {
+			hashByte &= 0xf
+		}
+		if bytes[i] > '9' && hashByte > 7 {
+			bytes[i] -= 32
+		}
+	}
+
+	return fmt.Sprintf("0x%s", string(bytes))
 }
 
 // Format formats the address.