38 lines
813 B
Go
38 lines
813 B
Go
package helpers
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import (
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"errors"
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"golang.org/x/crypto/cryptobyte"
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"golang.org/x/crypto/cryptobyte/asn1"
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)
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// Taken from crypto/ecdsa
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func EncodeSignatureToASN1(r, s []byte) ([]byte, error) {
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var b cryptobyte.Builder
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b.AddASN1(asn1.SEQUENCE, func(b *cryptobyte.Builder) {
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addASN1IntBytes(b, r)
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addASN1IntBytes(b, s)
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})
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return b.Bytes()
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}
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// addASN1IntBytes encodes in ASN.1 a positive integer represented as
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// a big-endian byte slice with zero or more leading zeroes.
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func addASN1IntBytes(b *cryptobyte.Builder, bytes []byte) {
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for len(bytes) > 0 && bytes[0] == 0 {
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bytes = bytes[1:]
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}
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if len(bytes) == 0 {
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b.SetError(errors.New("invalid integer"))
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return
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}
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b.AddASN1(asn1.INTEGER, func(c *cryptobyte.Builder) {
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if bytes[0]&0x80 != 0 {
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c.AddUint8(0)
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}
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c.AddBytes(bytes)
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})
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}
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