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add more documentation to ecdsa

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This commit is contained in:
Gibheer 2015-03-16 21:25:01 +01:00
parent f9807c7ccb
commit 6b355e272b
1 changed files with 17 additions and 10 deletions
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27
ecdsa.go
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@ -12,9 +12,8 @@ import (
"math/big" "math/big"
) )
const ( // This label is used as the type in the pem encoding of ECDSA private keys.
PemLabelEcdsa = "EC PRIVATE KEY" const PemLabelEcdsa = "EC PRIVATE KEY"
)
type ( type (
// This type handles the function calls to the ecdsa private key by // This type handles the function calls to the ecdsa private key by
@ -23,16 +22,20 @@ type (
private_key *ecdsa.PrivateKey private_key *ecdsa.PrivateKey
} }
// EcdsaPublicKey is the specific public key type for ecdsa. It implements the
// the PublicKey interface.
EcdsaPublicKey struct { EcdsaPublicKey struct {
public_key *ecdsa.PublicKey public_key *ecdsa.PublicKey
} }
// This struct is used to marshal and parse the ecdsa signature.
signatureEcdsa struct { signatureEcdsa struct {
R, S *big.Int R, S *big.Int
} }
) )
// Create a new ECDSA private key using the specified curve. // Create a new ECDSA private key using the specified curve.
// For available curves, please take a look at the crypto/elliptic package.
func NewPrivateKeyEcdsa(curve elliptic.Curve) (*EcdsaPrivateKey, error) { func NewPrivateKeyEcdsa(curve elliptic.Curve) (*EcdsaPrivateKey, error) {
key, err := ecdsa.GenerateKey(curve, rand.Reader) key, err := ecdsa.GenerateKey(curve, rand.Reader)
if err != nil { return nil, err } if err != nil { return nil, err }
@ -46,12 +49,12 @@ func LoadPrivateKeyEcdsa(raw []byte) (*EcdsaPrivateKey, error) {
return &EcdsaPrivateKey{key}, nil return &EcdsaPrivateKey{key}, nil
} }
// derive a public key from the private key // Create a new public key from the private key.
func (pr EcdsaPrivateKey) Public() PublicKey { func (pr EcdsaPrivateKey) Public() PublicKey {
return &EcdsaPublicKey{pr.private_key.Public().(*ecdsa.PublicKey)} return &EcdsaPublicKey{pr.private_key.Public().(*ecdsa.PublicKey)}
} }
// sign a message with the private key // Sign a message using the private key and the provided hash function.
func (pr EcdsaPrivateKey) Sign(message []byte, hash crypto.Hash) ([]byte, error) { func (pr EcdsaPrivateKey) Sign(message []byte, hash crypto.Hash) ([]byte, error) {
empty := make([]byte, 0) empty := make([]byte, 0)
if !hash.Available() { if !hash.Available() {
@ -62,12 +65,13 @@ func (pr EcdsaPrivateKey) Sign(message []byte, hash crypto.Hash) ([]byte, error)
return pr.private_key.Sign(rand.Reader, hashed_message.Sum(nil), hash) return pr.private_key.Sign(rand.Reader, hashed_message.Sum(nil), hash)
} }
// get the private key // This function returns the crypto.PrivateKey structure of the ECDSA key.
func (pr EcdsaPrivateKey) PrivateKey() crypto.PrivateKey { func (pr EcdsaPrivateKey) PrivateKey() crypto.PrivateKey {
return pr.private_key return pr.private_key
} }
// implement Pemmer interface // This function implements the Pemmer interface to marshal the private key
// into a pem block.
func (pr EcdsaPrivateKey) MarshalPem() (marshalledPemBlock, error) { func (pr EcdsaPrivateKey) MarshalPem() (marshalledPemBlock, error) {
asn1, err := x509.MarshalECPrivateKey(pr.private_key) asn1, err := x509.MarshalECPrivateKey(pr.private_key)
if err != nil { return nil, err } if err != nil { return nil, err }
@ -75,7 +79,7 @@ func (pr EcdsaPrivateKey) MarshalPem() (marshalledPemBlock, error) {
return pem.EncodeToMemory(&pem_block), nil return pem.EncodeToMemory(&pem_block), nil
} }
// load an ecdsa public key // This functoin loads an ecdsa public key from the asn.1 representation.
func LoadPublicKeyEcdsa(raw []byte) (*EcdsaPublicKey, error) { func LoadPublicKeyEcdsa(raw []byte) (*EcdsaPublicKey, error) {
raw_pub, err := x509.ParsePKIXPublicKey(raw) raw_pub, err := x509.ParsePKIXPublicKey(raw)
if err != nil { return nil, err } if err != nil { return nil, err }
@ -85,7 +89,8 @@ func LoadPublicKeyEcdsa(raw []byte) (*EcdsaPublicKey, error) {
return &EcdsaPublicKey{pub}, nil return &EcdsaPublicKey{pub}, nil
} }
// marshal the public key to a pem block // This function implements the Pemmer interface to marshal the public key into
// a pem block.
func (pu *EcdsaPublicKey) MarshalPem() (marshalledPemBlock, error) { func (pu *EcdsaPublicKey) MarshalPem() (marshalledPemBlock, error) {
asn1, err := x509.MarshalPKIXPublicKey(pu.public_key) asn1, err := x509.MarshalPKIXPublicKey(pu.public_key)
if err != nil { return nil, err } if err != nil { return nil, err }
@ -93,7 +98,9 @@ func (pu *EcdsaPublicKey) MarshalPem() (marshalledPemBlock, error) {
return pem.EncodeToMemory(&pem_block), nil return pem.EncodeToMemory(&pem_block), nil
} }
// verify a message using the ecdsa public key // This function verifies a message using the public key, signature and hash
// function.
// The hash function must be the same as was used to create the signature.
func (pu *EcdsaPublicKey) Verify(message []byte, signature_raw []byte, hash crypto.Hash) (bool, error) { func (pu *EcdsaPublicKey) Verify(message []byte, signature_raw []byte, hash crypto.Hash) (bool, error) {
var sig signatureEcdsa var sig signatureEcdsa
_, err := asn1.Unmarshal(signature_raw, &sig) _, err := asn1.Unmarshal(signature_raw, &sig)