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padding: implement ISO IEC9797-1 padding method 3 #319
This commit is contained in:
Sun Yimin
GitHub
parent
5734e67634
commit
069babe703
@ -6,7 +6,7 @@ import (
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"github.com/emmansun/gmsm/internal/alias"
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)
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// Add a single bit with value 1 to the end of the data.
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// Add a single bit with value 1 to the end of the data.
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// Then if necessary add bits with value 0 to the end of the data until the padded data is a multiple of n.
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//
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// https://en.wikipedia.org/wiki/ISO/IEC_9797-1
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@ -31,17 +31,21 @@ func (pad iso9797M2Padding) Unpad(src []byte) ([]byte, error) {
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if srcLen == 0 || srcLen%pad.BlockSize() != 0 {
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return nil, errors.New("padding: src length is not multiple of block size")
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}
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padStart := -1
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for i, b := range src[srcLen-pad.BlockSize() : srcLen] {
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if b == 0x80 {
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tail := src[srcLen-pad.BlockSize():]
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allZero := true
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padStart := 0
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for i := pad.BlockSize() - 1; i >= 0; i-- {
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if tail[i] == 0x80 {
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padStart = i
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} else if b != 0 && padStart >=0 {
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padStart = -1
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break
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}
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if tail[i] != 0 {
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allZero = false
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break
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}
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}
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if padStart >= 0 {
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return src[:srcLen-pad.BlockSize()+padStart], nil
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if !allZero {
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return nil, errors.New("padding: inconsistent padding bytes")
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}
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return src, nil
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return src[:srcLen-pad.BlockSize()+padStart], nil
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}
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@ -28,6 +28,7 @@ func Test_iso9797M2Padding_Pad(t *testing.T) {
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{"3 bytes", []byte{0, 1, 2}, []byte{0, 1, 2, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"2 bytes", []byte{0, 1}, []byte{0, 1, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"1 bytes", []byte{0}, []byte{0, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"0 bytes", []byte{}, []byte{0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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@ -62,10 +63,12 @@ func Test_iso9797M2Padding_Unpad(t *testing.T) {
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{"3 bytes", []byte{0, 1, 2}, []byte{0, 1, 2, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"2 bytes", []byte{0, 1}, []byte{0, 1, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"1 bytes", []byte{0}, []byte{0, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"0 bytes", []byte{}, []byte{0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"1 bytes with tag", []byte{0x80}, []byte{0x80, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"3 bytes with tag", []byte{0x80, 0, 0x80}, []byte{0x80, 0, 0x80, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"19 bytes with tag", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0x80, 0, 0x80}, []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 0x80, 0, 0x80, 0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"invalid src length", nil, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, true},
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{"inconsistent padding bytes", nil, []byte{0, 0x80, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, true},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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71
padding/iso9797_m3.go
Normal file
71
padding/iso9797_m3.go
Normal file
@ -0,0 +1,71 @@
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package padding
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import (
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"errors"
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"github.com/emmansun/gmsm/internal/byteorder"
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)
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// The padded data comprises (in this order):
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//
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// - The length of the unpadded data (in bits) expressed in big-endian binary in n bits (i.e. one cipher block)
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// - The unpadded data
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// - As many (possibly none) bits with value 0 as are required to bring the total length to a multiple of n bits
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// It is not necessary to transmit or store the padding bits, because the recipient can regenerate them, knowing the length of the unpadded data and the padding method used.
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//
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// https://en.wikipedia.org/wiki/ISO/IEC_9797-1#Padding_method_3
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// also GB/T 17964-2021 C.4 Padding method 3
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type iso9797M3Padding uint
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func (pad iso9797M3Padding) BlockSize() int {
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return int(pad)
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}
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func (pad iso9797M3Padding) Pad(src []byte) []byte {
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srcLen := len(src)
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overhead := pad.BlockSize() - srcLen%pad.BlockSize()
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if overhead == pad.BlockSize() && srcLen > 0 {
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overhead = 0
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}
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var head, tail []byte
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total := srcLen + overhead + pad.BlockSize()
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if cap(src) >= total {
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head = src[:total]
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} else {
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head = make([]byte, total)
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}
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tail = head[srcLen+pad.BlockSize():]
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clear(head[:pad.BlockSize()])
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copy(head[pad.BlockSize():], src)
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if overhead > 0 {
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clear(tail)
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}
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byteorder.BEPutUint64(head[8:], uint64(srcLen*8))
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return head
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}
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// Unpad decrypted plaintext, non-constant-time
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func (pad iso9797M3Padding) Unpad(src []byte) ([]byte, error) {
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srcLen := len(src)
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if srcLen < 2*pad.BlockSize() || srcLen%pad.BlockSize() != 0 {
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return nil, errors.New("padding: invalid src length")
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}
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for _, b := range src[:8] {
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if b != 0 {
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return nil, errors.New("padding: invalid padding header")
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}
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}
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dstLen := int(byteorder.BEUint64(src[8:pad.BlockSize()])/8)
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if dstLen < 0 || dstLen > srcLen-pad.BlockSize() {
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return nil, errors.New("padding: invalid padding header")
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}
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padded := src[pad.BlockSize()+dstLen:]
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for _, b := range padded {
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if b != 0 {
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return nil, errors.New("padding: invalid padding bytes")
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}
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}
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return src[pad.BlockSize() : pad.BlockSize()+dstLen], nil
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}
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84
padding/iso9797_m3_test.go
Normal file
84
padding/iso9797_m3_test.go
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@ -0,0 +1,84 @@
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package padding
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import (
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"reflect"
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"testing"
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)
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func Test_iso9797M3Padding_Pad(t *testing.T) {
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iso9797 := NewISO9797M3Padding(16)
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tests := []struct {
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name string
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src []byte
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want []byte
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}{
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{"16 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 128, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}},
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{"15 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 120, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0}},
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{"14 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 112, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 0, 0}},
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{"13 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 104, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0, 0, 0}},
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{"12 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 96, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 0, 0, 0, 0}},
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{"11 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 88, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0, 0, 0}},
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{"10 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 80, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0}},
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{"9 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 72, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0}},
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{"8 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 64, 0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"7 bytes", []byte{0, 1, 2, 3, 4, 5, 6}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 56, 0, 1, 2, 3, 4, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"6 bytes", []byte{0, 1, 2, 3, 4, 5}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 48, 0, 1, 2, 3, 4, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"5 bytes", []byte{0, 1, 2, 3, 4}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 40, 0, 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"4 bytes", []byte{0, 1, 2, 3}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 1, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"3 bytes", []byte{0, 1, 2}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 24, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"2 bytes", []byte{0, 1}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"1 bytes", []byte{1}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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{"0 bytes", []byte{}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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if got := iso9797.Pad(tt.src); !reflect.DeepEqual(got, tt.want) {
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t.Errorf("iso9797M2Padding.Pad() = %v, want %v", got, tt.want)
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}
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})
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}
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}
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func Test_iso9797M3Padding_Unpad(t *testing.T) {
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iso9797 := NewISO9797M3Padding(16)
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tests := []struct {
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name string
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want []byte
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src []byte
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wantErr bool
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}{
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{"16 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 128, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}, false},
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{"15 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 120, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 0}, false},
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{"14 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 112, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 0, 0}, false},
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{"13 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 104, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 0, 0, 0}, false},
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{"12 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 96, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 0, 0, 0, 0}, false},
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{"11 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 88, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 0, 0, 0, 0, 0}, false},
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{"10 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 80, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 0, 0, 0, 0, 0, 0}, false},
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{"9 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7, 8}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 72, 0, 1, 2, 3, 4, 5, 6, 7, 8, 0, 0, 0, 0, 0, 0, 0}, false},
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{"8 bytes", []byte{0, 1, 2, 3, 4, 5, 6, 7}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 64, 0, 1, 2, 3, 4, 5, 6, 7, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"7 bytes", []byte{0, 1, 2, 3, 4, 5, 6}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 56, 0, 1, 2, 3, 4, 5, 6, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"6 bytes", []byte{0, 1, 2, 3, 4, 5}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 48, 0, 1, 2, 3, 4, 5, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"5 bytes", []byte{0, 1, 2, 3, 4}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 40, 0, 1, 2, 3, 4, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"4 bytes", []byte{0, 1, 2, 3}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 0, 1, 2, 3, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"3 bytes", []byte{0, 1, 2}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 24, 0, 1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"2 bytes", []byte{0, 1}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"1 bytes", []byte{1}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"0 bytes", []byte{}, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, false},
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{"invalid length", nil, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, true},
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{"invalid padding header", nil, []byte{1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, true},
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{"invalid padding header 2", nil, []byte{0, 0, 0, 0, 0, 0, 0, 0, 15, 15, 15, 15, 15, 15, 15, 15, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}, true},
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{"invalid padding bytes", nil, []byte{0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1}, true},
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}
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for _, tt := range tests {
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t.Run(tt.name, func(t *testing.T) {
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got, err := iso9797.Unpad(tt.src)
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if (err != nil) != tt.wantErr {
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t.Errorf("case %v: iso9797M2Padding.Unpad() error = %v, wantErr %v", tt.name, err, tt.wantErr)
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return
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}
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if !reflect.DeepEqual(got, tt.want) {
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t.Errorf("case %v: iso9797M2Padding.Unpad() = %v, want %v", tt.name, got, tt.want)
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}
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})
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}
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}
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@ -28,3 +28,10 @@ func NewISO9797M2Padding(blockSize uint) Padding {
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}
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return iso9797M2Padding(blockSize)
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}
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func NewISO9797M3Padding(blockSize uint) Padding {
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if blockSize == 0 || blockSize > 255 {
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panic("padding: invalid block size")
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}
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return iso9797M3Padding(blockSize)
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}
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