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cipher: stream cipher seeking by counter value #336

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cipher: stream cipher seeking by counter value#336
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@tarcieri
tarcieri
opened on Oct 14, 2020

Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.

The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.

I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.

cc @newpavlov

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cipher: stream cipher seeking by counter value · Issue #336 · RustCrypto/traits · GitHub
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    cipher: stream cipher seeking by counter value #336
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    cipher: stream cipher seeking by counter value#336
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    cipherBlock and stream cipher crate
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    @tarcieri
    tarcieri
    opened on Oct 14, 2020
    Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.
    The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.
    I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.
    cc @newpavlov
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var __m = "*";
var __re = new RegExp('^' + ".*" + '
cipher: stream cipher seeking by counter value · Issue #336 · RustCrypto/traits · GitHub
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      cipher: stream cipher seeking by counter value #336
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      cipher: stream cipher seeking by counter value#336
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      cipherBlock and stream cipher crate
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      @tarcieri
      tarcieri
      opened on Oct 14, 2020
      Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.
      The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.
      I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.
      cc @newpavlov
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try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
cipher: stream cipher seeking by counter value · Issue #336 · RustCrypto/traits · GitHub
        Skip to content
        cipher: stream cipher seeking by counter value #336
        Closed
        Closed
        cipher: stream cipher seeking by counter value#336
        Labels
        cipherBlock and stream cipher crate
        Description
        @tarcieri
        tarcieri
        opened on Oct 14, 2020
        Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.
        The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.
        I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.
        cc @newpavlov
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cipher: stream cipher seeking by counter value · Issue #336 · RustCrypto/traits · GitHub
          Skip to content
          cipher: stream cipher seeking by counter value #336
          Closed
          Closed
          cipher: stream cipher seeking by counter value#336
          Labels
          cipherBlock and stream cipher crate
          Description
          @tarcieri
          tarcieri
          opened on Oct 14, 2020
          Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.
          The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.
          I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.
          cc @newpavlov
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cipher: stream cipher seeking by counter value · Issue #336 · RustCrypto/traits · GitHub
            Skip to content
            cipher: stream cipher seeking by counter value #336
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            cipher: stream cipher seeking by counter value#336
            Labels
            cipherBlock and stream cipher crate
            Description
            @tarcieri
            tarcieri
            opened on Oct 14, 2020
            Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.
            The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.
            I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.
            cc @newpavlov
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cipher: stream cipher seeking by counter value · Issue #336 · RustCrypto/traits · GitHub
              Skip to content
              cipher: stream cipher seeking by counter value #336
              Closed
              Closed
              cipher: stream cipher seeking by counter value#336
              Labels
              cipherBlock and stream cipher crate
              Description
              @tarcieri
              tarcieri
              opened on Oct 14, 2020
              Seeking by a counter value (e.g. NIST SP800-38D) is an exceedingly common operation, whether a stream cipher is a block cipher in counter mode (e.g. AES-CTR), or if a stream cipher uses an underlying block-based construction (ChaCha20, Salsa20). As it were, such seeking is necessary to implement AES-GCM, ChaCha20Poly1305, and XSalsa20Poly1305.
              The current SyncStreamCipherSeek trait provides the ability to seek anywhere in the keystream at a byte-level granularity. This complicates the internal buffering logic by requiring stream ciphers to work at non-block-oriented offsets.
              I think it'd be nice to have a trait that just accepts a counter value, rather than one which specifies a SeekNum-style byte offset. If we had such a trait, I think we could implement SyncStreamCipherSeek-like behavior in a single place, as opposed to the current state of affairs where internally the chacha20 and salsa20 crates contain copy-pasted code from ctr::Ctr128.
              cc @newpavlov
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